Document and Entity Information	12 Months Ended
Document and Entity Information	Dec. 31, 2017 shares
Document Information [Line Items]
Document Type	20-F
Amendment Flag	false
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	FY
Trading Symbol	MOMO
Entity Registrant Name	Momo Inc.
Entity Central Index Key	0001610601
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Class A Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding	314,060,843
Class B Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding	84,364,466

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets
Cash and cash equivalents	$ 685,827	$ 257,564
Term deposits	373,794	393,759
Accounts receivable, net of allowance for doubtful accounts of $nil and $90 as of December 31, 2016 and 2017 respectively	39,597	36,078
Amount due from related parties	5,143	88
Prepaid expenses and other current assets	82,717	32,592
Deferred tax assets, current		72
Short-term investment	1,614
Total current assets	1,188,692	720,153
Property and equipment, net	39,762	13,932
Intangible assets	7,462
Rental deposits	2,651	920
Long term investments	44,337	31,932
Other non-current assets	8,495	2,593
Deferred tax assets, non-current	7,197	208
Goodwill	3,401
Total assets	1,301,997	769,738
Current liabilities
Accounts payable (including accounts payable of the consolidated VIE without recourse to the Company of $36,812 and $54,937 as of December 31, 2016 and 2017, respectively)	74,535	40,457
Deferred revenue (including deferred revenue of the consolidated VIE without recourse to the Company of $41,277 and $64,788 as of December 31, 2016 and 2017, respectively)	64,865	41,277
Accrued expenses and other current liabilities (including accrued expenses and other current liabilities of the consolidated VIE without recourse to the Company of $6,632 and $30,802 as of December 31, 2016 and 2017, respectively)	87,809	39,965
Amount due to related parties (including amount due to related parties of the consolidated VIE without recourse to the Company of $1,510 and $29 as of December 31, 2016 and 2017, respectively)	5,804	8,117
Income tax payable (including income tax payable of the consolidated VIE without recourse to the Company of $3,881 and $11,765 as of December 31, 2016 and 2017, respectively)	27,033	3,881
Total current liabilities	260,046	133,697
Deferred tax liabilities, non-current	1,866
Other non-current liabilities	2,305	2,022
Total liabilities	264,217	135,719
Commitments and contingencies (Note14)
Equity
Treasury stock	(64,494)	(64,494)
Additional paid-in capital	713,721	663,498
Retained earnings	369,707	51,141
Accumulated other comprehensive (loss)/ income	15,954	(16,168)
Noncontrolling interest	2,849
Total equity	1,037,780	634,019
Total liabilities and equity	1,301,997	769,738
Class A Common Stock [Member]
Equity
Ordinary shares, value	34	32
Class B Common Stock [Member]
Equity
Ordinary shares, value	$ 9	$ 10

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Allowance for doubtful accounts	$ 90	$ 0
Accounts payable of consolidated VIE without recourse	74,535	40,457
Deferred revenue of consolidated VIE without recourse	64,865	41,277
Accrued expenses and other current liabilities of consolidated VIE without recourse	87,809	39,965
Amount due to related parties of the consolidated VIE without recourse the Company	5,804	8,117
Income tax payable of the consolidated VIE without recourse	27,033	3,881
Beijing Momo Technology Co., Ltd. [Member]
Allowance for doubtful accounts	90	0
Accounts payable of consolidated VIE without recourse	54,937	36,812
Deferred revenue of consolidated VIE without recourse	64,788	41,277
Accrued expenses and other current liabilities of consolidated VIE without recourse	30,802	6,632
Amount due to related parties of the consolidated VIE without recourse the Company	29	1,510
Income tax payable of the consolidated VIE without recourse	$ 11,765	$ 3,881
Class A Common Stock [Member]
Ordinary shares, par value	$ 0.0001	$ 0.0001
Ordinary shares, shares authorized	800,000,000	800,000,000
Ordinary shares, shares issued	314,060,843	292,062,065
Ordinary shares, shares outstanding	314,060,843	292,062,065
Class B Common Stock [Member]
Ordinary shares, par value	$ 0.0001	$ 0.0001
Ordinary shares, shares authorized	100,000,000	100,000,000
Ordinary shares, shares issued	84,364,466	96,886,370
Ordinary shares, shares outstanding	84,364,466	96,886,370

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Net revenues	$ 1,318,271	$ 553,098	$ 133,988
Cost and expenses:
Cost of revenues (including share-based compensation of $915, $2,785 and $2,014 in 2015, 2016 and 2017, respectively)	(649,275)	(241,463)	(30,312)
Research and development (including share-based compensation of $3,502, $5,646 and $8,793 in 2015, 2016 and 2017, respectively)	(51,491)	(31,399)	(23,265)
Sales and marketing (including share-based compensation of $3,780, $5,880 and $11,723 in 2015, 2016 and 2017 respectively)	(217,437)	(97,173)	(52,631)
General and administrative (including share-based compensation of $9,185, $17,395 and $27,127 in 2015, 2016 and 2017, respectively)	(62,581)	(38,983)	(22,879)
Total cost and expenses	(980,784)	(409,018)	(129,087)
Other operating income	23,379	406	713
Income from operations	360,866	144,486	5,614
Interest income	21,635	8,194	7,805
Impairment loss on long-term investments	(4,386)	(5,765)
Income before income tax and share of income on equity method investments	378,115	146,915	13,419
Income tax expense	(65,980)	(5,136)	(92)
Income before share of income on equity method investments	312,135	141,779	13,327
Share of income on equity method investments	5,889	3,471	370
Net income	318,024	145,250	13,697
Less: net loss attributable to non-controlling interest	(542)
Net income attributable to Momo Inc.	318,566	145,250	13,697
Net income attributable to ordinary shareholders	$ 318,566	$ 145,250	$ 13,697
Net income per share attributable to ordinary shareholders
Basic	$ 0.81	$ 0.38	$ 0.04
Diluted	$ 0.77	$ 0.36	$ 0.03
Weighted average shares used in calculating net income per ordinary share
Basic	394,549,323	377,335,923	342,646,282
Diluted	415,265,078	407,041,165	401,396,548

Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based compensation	$ 49,657	$ 31,706	$ 17,382
Cost Of Revenues [Member]
Share-based compensation	2,014	2,785	915
Research And Development [Member]
Share-based compensation	8,793	5,646	3,502
Sales And Marketing [Member]
Share-based compensation	11,723	5,880	3,780
General And Administrative [Member]
Share-based compensation	$ 27,127	$ 17,395	$ 9,185

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net Income	$ 318,024	$ 145,250	$ 13,697
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustment	32,170	(11,642)	(3,499)
Comprehensive income	350,194	133,608	10,198
Less: comprehensive loss attributed to the non-controlling interest	(494)
Comprehensive income attributable to Momo Inc.	$ 350,688	$ 133,608	$ 10,198

Consolidated Statements of Changes in Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	(Accumulated Deficit)/ Retained Earning [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Non-controlling Interests [Member]
Balance at Dec. 31, 2014	$ 440,391	$ 40	$ 613,678	$ (64,494)	$ (107,806)	$ (1,027)
Balance, Shares at Dec. 31, 2014		377,756,110
Net Income	13,697				13,697
Share-based compensation	17,382		17,382
Issuance of ordinary shares in connection with exercise of options and vesting of restricted share units	$ 415	$ 1	414
Issuance of ordinary shares in connection with exercise of options and vesting of restricted share units	5,995,293	5,995,293
Foreign currency translation adjustment	$ (3,499)					(3,499)
Balance at Dec. 31, 2015	468,386	$ 41	631,474	(64,494)	(94,109)	(4,526)
Balance, Shares at Dec. 31, 2015		383,751,403
Net Income	145,250				145,250
Share-based compensation	31,706		31,706
Issuance of ordinary shares in connection with exercise of options and vesting of restricted share units	$ 319	$ 1	318
Issuance of ordinary shares in connection with exercise of options and vesting of restricted share units	5,197,032	5,197,032
Foreign currency translation adjustment	$ (11,642)					(11,642)
Balance at Dec. 31, 2016	634,019	$ 42	663,498	(64,494)	51,141	(16,168)
Balance, Shares at Dec. 31, 2016		388,948,435
Net Income	318,024				318,566		$ (542)
Share-based compensation	49,657		49,657
Issuance of ordinary shares in connection with exercise of options and vesting of restricted share units	$ 567	$ 1	566
Issuance of ordinary shares in connection with exercise of options and vesting of restricted share units	9,476,874	9,476,874
Addition in noncontrolling interest of a subsidiary	$ 3,343						3,343
Foreign currency translation adjustment	32,170					32,122	48
Balance at Dec. 31, 2017	$ 1,037,780	$ 43	$ 713,721	$ (64,494)	$ 369,707	$ 15,954	$ 2,849
Balance, Shares at Dec. 31, 2017		398,425,309

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities
Net Income	$ 318,024	$ 145,250	$ 13,697
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation of property and equipment	11,722	8,404	6,646
Amortization of intangible assets	714
Share-based compensation	49,657	31,706	17,382
Share of income on equity method investments	(5,889)	(3,471)	(370)
Impairment loss on long-term investments	4,386	5,765
Impairment loss on intangible assets	191
Loss on disposal of property and equipment	17	15	5
Provision of allowance for doubtful accounts	85
Changes in operating assets and liabilities
Accounts receivable	(1,226)	(22,978)	(8,538)
Prepaid expenses and other current assets	(45,824)	(15,634)	(11,247)
Amount due from related parties	(4,943)	1,037	(1,218)
Deferred tax assets	(6,790)	(284)
Rental deposits	(1,590)	(304)	38
Other non-current assets	(750)
Accounts payable	25,778	32,019	5,274
Income tax payable	22,683	3,946
Deferred revenue	20,417	15,546	12,996
Accrued expenses and other current liabilities	43,303	15,456	20,671
Amount due to related parties	(2,496)	1,642	88
Deferred tax liability	(145)
Other non-current liabilities	283	196	1,828
Net cash provided by operating activities	427,607	218,311	57,252
Cash flows from investing activities
Purchase of property and equipment	(32,314)	(7,026)	(13,521)
Proceeds from disposal of property and equipment	8	63
Payment for long term investments	(8,003)	(14,542)	(17,859)
Prepayment for long term investments	(7,561)	(2,635)	(2,000)
Payment for acquired intangible assets	(2,993)
Purchase of term deposits	(592,432)	(509,612)	(450,000)
Cash received on maturity of term deposits	617,566	415,404	150,000
Payment for short term investments	(2,367)
Cash received from sales of short term investment	786
Net cash used in investing activities	(27,310)	(118,348)	(333,380)
Cash flows from financing activities
Payment for IPO costs			(2,634)
Capital contribution from non-controlling interest shareholder	73
Deferred payment of purchase of property and equipment	(217)	(319)
Proceeds from exercise of share options	564	333	401
Net cash provided by (used in) financing activities	420	14	(2,233)
Effect of exchange rate on cash and cash equivalents	27,546	(11,882)	(3,138)
Net increase (decrease) in cash and cash equivalents	428,263	88,095	(281,499)
Cash and cash equivalents at the beginning of year	257,564	169,469	450,968
Cash and cash equivalents at the end of year	685,827	257,564	169,469
Non-cash investing and financing activities
Payable for purchase of property and equipment	7,265	623	765
Payable for repurchase of ordinary shares	$ 6,450	$ 6,450	$ 6,450

Organization and Principal Activities

12 Months Ended

Dec. 31, 2017

Text Block [Abstract]

Organization and Principal Activities

1.	ORGANIZATION AND PRINCIPAL ACTIVITIES

Momo Inc. (the “Company”, formerly known as Momo Technology Company Limited) is the holding company for a group of companies, which is incorporated in the British Virgin Islands (“BVI”) on November 23, 2011. In July 2014, the Company was redomiciled in the Cayman Islands (“Cayman”) as an exempted company registered under the laws of the Cayman Islands, and was renamed Momo Inc. The Company, its subsidiaries, its consolidated variable interest entity (“VIE”) and VIE’s subsidiaries (collectively the “Group”) are principally engaged in providing mobile-based social networking services. The Group started its operation in July 2011. The Group started its monetization in the third quarter of 2013, by offering a platform for live video services, value-added service, mobile games and mobile marketing services.

As of December 31, 2017, details of the Company’s subsidiaries, VIE and VIE’s subsidiaries are as follows:

Date of
incorporation or
acquisition

Place of
incorporation

Percentage
of economic
ownership

Subsidiaries

Momo Technology HK Company Limited (“Momo HK”)

December 5, 2011

Hong Kong

100

Beijing Momo Information Technology Co., Ltd. (“Beijing Momo IT”)

March 9, 2012

PRC

100

Momo Technology Overseas Holding Company Limited (“Momo BVI”)

March 5, 2014

BVI

100

Momo Information Technologies Corp. (“Momo US”)

March 7, 2014

100

VIE

Beijing Momo Technology Co., Ltd. (“Beijing Momo”)

July 7, 2011

PRC

N/A

VIE’s subsidiaries

Chengdu Momo Technology Co., Ltd. (“Chengdu Momo”)

May 9, 2013

PRC

N/A

Shanghai Momo Technology Co., Ltd. (“Shanghai Momo”)

January 19, 2015

PRC

N/A

Chengdu Biyou Technology Co., Ltd. (“Chengdu Biyou”)

October 16, 2015

PRC

N/A

Tianjin Heer Technology Co., Ltd (“Tianjin Heer”)

March 7, 2016

PRC

N/A

Momo Pictures Co., Ltd.

November 11, 2016

PRC

N/A

QOOL Media (Tianjin) Co., Ltd

November 16, 2016

PRC

N/A

Zhejiang Shengdian Digital Network Co., Ltd. (“Zhejiang Shengdian”)

March 31, 2017

PRC

N/A

Beijing Santi Cloud Union Technology Co., Ltd. (“Santi”)

June 30,2017

PRC

N/A

Loudi Momo Technology Co., Ltd. (“Loudi Momo”)

July 17, 2017

PRC

N/A

Changsha Heer Network Co., Ltd. (“Changsha Heer”)

September 20,2017

PRC

N/A

Beijing Santi Cloud Time Technology Co., Ltd.

September 26,2017

PRC

N/A

*	These entities are controlled by the Company pursuant to the contractual arrangements disclosed below.

The Company was established on November 23, 2011 with share capital of $15, which was 65% owned by Mr. Yan Tang, 20% owned by Mr. Yong Li, 8% owned by Mr. Xiaoliang Lei, and 7% owned by Mr. Zhiwei Li, (Yan Tang, Yong Li, Xiaoliang Lei and Zhiwei Li are collectively referred to as “Founders”) as a vehicle for the group reorganization.

The Group commenced its business in China in July 2011 through Beijing Momo which has subsequently become the Group’s VIE through the contractual arrangements described below in “the VIE arrangements”.

Beijing Momo was established by the Founders in Beijing, the People’s Republic of China (“PRC”), as a limited liability company on July 7, 2011, which was 65% owned by Mr. Yan Tang, 20% owned by Mr. Yong Li, 8% owned by Mr. Xiaoliang Lei, and 7% owned by Mr. Zhiwei Li. Beijing Momo and its subsidiaries principally engaged in the provision of substantially all of the Group’s services in the PRC.

The Company owns 100% of the equity interests in Momo HK, an intermediate holding company incorporated in Hong Kong on December 5, 2011, which owns 100% of the equity interests in Beijing Momo IT, a wholly foreign-owned enterprise (“WFOE”), incorporated in the PRC by the Company on March 9, 2012.

The Company entered into a group reorganization by way of entering into a series of contractual arrangements between its WFOE, VIE and the Company on April 18, 2012. Immediately after the reorganization, the Founders controlled the Company, WFOE and Beijing Momo; therefore, the reorganization was accounted for as a transaction among entities under common control. Accordingly, the accompanying audited consolidated financial statements have been prepared by using historical cost basis and include the assets, liabilities, revenue, expenses and cash flows that were directly attributable to Beijing Momo for all periods presented.

In December 2014, the Company completed its IPO and a concurrent private placement, upon which the Company’s ordinary shares were divided into Class A ordinary shares and Class B ordinary shares. Holders of Class A ordinary shares are entitled to one vote per share, while holders of Class B ordinary shares are entitled to ten votes per share. Each Class B ordinary share is convertible into one Class A ordinary share at any time by the holder thereof, while Class A ordinary shares are not convertible to Class B ordinary shares under any circumstances. The Company newly issued 45,688,888 Class A ordinary shares, consist of (i) 36,800,000 Class A ordinary shares offered through the IPO, and (ii) 8,888,888 Class A ordinary shares issued in connection with the concurrent private placement. All of the Company’s Series A, Series B, Series C and Series D shares were automatically converted upon IPO into 200,718,811 Class A ordinary shares.

The VIE arrangements

PRC regulations currently limit direct foreign ownership of business entities providing value-added telecommunications services, advertising services and internet services in the PRC where certain licenses are required for the provision of such services. To comply with these PRC regulations, Beijing Momo IT and Beijing Momo’s shareholders entered into various contractual arrangements whereby the shareholders’ claim to the economic benefits of Beijing Momo and their ability to control the activities of Beijing Momo were transferred to Beijing Momo IT.

The Group provides substantially all of its services in China through Beijing Momo, Chengdu Momo, Tianjin Heer and Loudi Momo, which hold the operating licenses and approvals to enable the Group to provide such mobile internet content services in the PRC. The equity interests of Beijing Momo are legally held by certain employees and shareholders of the Company (“Nominee Shareholders”).

The Company obtained control over Beijing Momo through Beijing Momo IT on April 18, 2012 by entering into a series of contractual arrangements between Beijing Momo IT, Beijing Momo and its Nominee Shareholders that enable the Company to (1) have power to direct the activities that most significantly affects the economic performance of the VIE, and (2) receive the economic benefits of the VIE that could be significant to the VIE. Accordingly, the Company is considered the primary beneficiary of the VIE and has consolidated the VIE’s financial results of operations, assets and liabilities in the Company’s consolidated financial statements. In making the conclusion that the Company is the primary beneficiary of the VIE, the Company’s rights under the Power of Attorney also provide the Company’s abilities to direct the activities that most significantly impact the VIE’s economic performance. The Company also believes that this ability to exercise control ensures that the VIE will continue to execute and renew the Exclusive Technology Consulting and Management Services Agreement and pay service fees to the Company. By charging service fees in whatever amounts the Company deems fit, and by ensuring that the Exclusive Technology Consulting and Management Services Agreement is executed and renewed indefinitely, the Company has the rights to receive substantially all of the economic benefits from the VIE.

To further strengthen the Company’s corporate structure, the Group amended its Power of Attorney, Exclusive Call Option Agreement and Equity Interest Pledge Agreement with the Nominee Shareholders and also entered into the Spousal Consent Letters with the Nominee Shareholders in April 2014, and amended the Exclusive Cooperation Agreements and Supplemental Agreements in August 2014. There was no substantial change to the term and condition of the VIE agreements and the change had no impact on to the Company’s VIE consolidation. The following is a summary of the contractual agreements that the Company, through Beijing Momo IT, entered into with Beijing Momo and its Nominee Shareholders, as amended and entered into on April 18, 2014 and August 31, 2014:

Agreements that provide the Company effective control over the VIE:

(1)

Power of Attorney

Pursuant to the Power of Attorney, the Nominee Shareholders of Beijing Momo each irrevocably appointed Beijing Momo IT as the attorney-in-fact to act on their behalf on all matters pertaining to Beijing Momo and to exercise all of their rights as a shareholder of Beijing Momo, including but not limited to convene, attend and vote on their behalf at shareholders’ meetings, designate and appoint directors and senior management members. Beijing Momo IT may authorize or assign its rights under this appointment to a person as approved by its board of directors at its sole discretion. Each power of attorney will remain in force until the shareholder ceases to hold any equity interest in Beijing Momo. The Company believes the Powers of Attorney can demonstrate the power of its PRC subsidiary (Beijing Momo IT) to direct how the VIE should conduct its daily operations.

(2)

Exclusive Call Option Agreement

Under the Exclusive Call Option Agreement among Beijing Momo IT, Beijing Momo and Nominee Shareholders of Beijing Momo, each of the Nominee Shareholders irrevocably granted Beijing Momo IT or its designated representative(s) an exclusive option to purchase, to the extent permitted under PRC law, all or part of his, her or its equity interests in Beijing Momo at the consideration equal to the nominal price or at lowest price as permitted by PRC laws.

Beijing Momo IT or its designated representative(s) have sole discretion as to when to exercise such options, either in part or in full. Without Beijing Momo IT’s written consent, the Nominee Shareholders of Beijing Momo shall not transfer, donate, pledge, or otherwise dispose any equity interests of Beijing Momo in any way. In addition, any consideration paid by Beijing Momo IT to the Nominee Shareholders of Beijing Momo in exercising the option shall be transferred back to Beijing Momo IT or its designated representative(s). This agreement could be terminated when all the shareholders’ equity were acquired by the WFOE or its designated representative(s) subject to the law of People’s Republic of China.

In addition, Beijing Momo irrevocably granted Beijing Momo IT an exclusive and irrevocable option to purchase any or all of the assets owned by Beijing Momo at the lowest price permitted under PRC law. Without Beijing Momo IT’s prior written consent, Beijing Momo and its Nominee Shareholders will not sell, transfer, mortgage or otherwise dispose of Beijing Momo’s material assets, legal or beneficial interests or revenues of more than RMB500,000 or allow an encumbrance on any interest in Beijing Momo.

(3)

Spousal Consent Letters

On April 18, 2014, each spouse of the married Nominee Shareholders of Beijing Momo entered into a Spousal Consent Letter, which unconditionally and irrevocably agreed that the equity interests in Beijing Momo held by and registered in the name of their spouse will be disposed of pursuant to the Equity Interest Pledge Agreement, the Exclusive Call Option Agreement, and the Power of Attorney. Each spouse agreed not to assert any rights over the equity interests in Beijing Momo held by their spouse. In addition, in the event that the spouse obtains any equity interests in Beijing Momo held by their spouse for any reason, they agreed to be bound by the contractual arrangements.

Agreements that transfer economic benefits to the Company:

(1)

Exclusive Cooperation Agreements and Supplemental Agreements

In August 2014, Beijing Momo IT entered into an Exclusive Cooperation Agreement and a Supplemental Agreement with Beijing Momo and Chengdu Momo, respectively, to supersede the Exclusive Technology Consulting and Management Services Agreements signed in April 2012 by Beijing Momo IT and Beijing Momo. In May 2016, Beijing Momo IT entered into an Exclusive Cooperation Agreement and a Supplemental Agreement with Tianjin Heer. In December 2017, Beijing Momo IT entered into an Exclusive Cooperation Agreement and a Supplemental Agreement with Loudi Momo. Pursuant to the agreements, Beijing Momo IT has the exclusive right to provide, among other things, licenses, copyrights, technical and non-technical services to Beijing Momo, Chengdu Momo , Tianjin Heer and Loudi Momo and receive service fees and license fees as consideration. Beijing Momo, Chengdu Momo , Tianjin Heer and Loudi Momo will maintain a pre-determined level of operating profit and remit the excess operating profit, if any, to Beijing Momo IT as the consideration of the licenses, copyrights, technical and non-technical services provided by Beijing Momo IT. The agreements will remain effective for 10 years. At the sole discretion of Beijing Momo IT, the agreements could be renewed on applicable expirations dates, or Beijing Momo IT, Beijing Momo, Chengdu Momo, Tianjin Heer and Loudi Momo could enter into other exclusive agreements.

For the years ended December 31, 2015, 2016 and 2017, Beijing Momo IT charged Beijing Momo, Chengdu Momo, Tianjin Heer and Loudi Momo a service fee of $112,043, $319,018 and $662,503 at the WFOE’s discretion, respectively.

Since Beijing Momo IT has effectively controlled Beijing Momo through Power of Attorney, Equity Interest Pledge Agreement and Exclusive Call Option Agreement, Beijing Momo IT has the right to adjust the service fees at its sole discretion. The agreement shall remain effective for ten years. At the discretion of Beijing Momo IT, this agreement could be renewed on applicable expiration dates, or Beijing Momo IT and Beijing Momo could enter into another exclusive agreement.

(2)

Equity Interest Pledge Agreement

Under the equity interest pledge agreement among Beijing Momo IT and each of the Nominee Shareholders of Beijing Momo, the Nominee Shareholders pledged all of their equity interests in Beijing Momo to Beijing Momo IT to guarantee Beijing Momo’s and its shareholders’ payment obligations arising from the Exclusive Technology Consulting and Management Service Agreement, Business Operation Agreement and Exclusive Call Option Agreement, including but not limited to, the payments due to Beijing Momo IT for services provided.

If Beijing Momo or any of its Nominee Shareholders breaches its contractual obligations under the above agreements, Beijing Momo IT, as the pledgee, will be entitled to certain rights and entitlements, including receiving priority proceeds from the auction or sale of whole or part of the pledged equity interests of Beijing Momo in accordance with PRC legal procedures. During the term of the pledge, the shareholders of Beijing Momo shall cause Beijing Momo not to distribute any dividends and if they receive any dividends generated by the pledged equity interests, they shall transfer such received amounts to an account designated by Beijing Momo IT according to the instruction of Beijing Momo IT.

The pledge will remain binding until Beijing Momo and its Nominee Shareholders has fully performed all their obligations under the Exclusive Cooperation Agreements and Supplemental Agreements, Business Operations Agreement and Exclusive Call Option Agreement.

(3)

Business Operations Agreement

Under the Business Operations Agreement among Beijing Momo IT, Beijing Momo and the Nominee Shareholders of Beijing Momo, without the prior written consent of Beijing Momo IT or its designated representative(s), Beijing Momo shall not conduct any transaction that may substantially affect the assets, business, operation or interest of Beijing Momo IT. Beijing Momo and Nominee Shareholders shall also follow Beijing Momo IT’s instructions on management of Beijing Momo’s daily operation, finance and employee matters and appoint the nominee(s) designated by Beijing Momo IT as the director(s) and senior management members of Beijing Momo. In the event that any agreements between Beijing Momo IT and Beijing Momo terminates, Beijing Momo IT has the sole discretion to determine whether to continue any other agreements with Beijing Momo. Beijing Momo IT is entitled to any dividends or other interests declared by Beijing Momo and the shareholders of Beijing Momo have agreed to promptly transfer such dividends or other interests to Beijing Momo IT. The agreement shall remain effective for 10 years. At the discretion of Beijing Momo IT, this agreement will be renewed on applicable expiration dates, or Beijing Momo IT and Beijing Momo will enter into another exclusive agreement.

Through these contractual agreements, the Company has the ability to effectively control the VIE and is also able to receive substantially all the economic benefits of the VIE.

Risk in relation to the VIE structure

The Company believes that Beijing Momo IT and Beijing Momo’s contractual arrangements with the VIE are in compliance with PRC law and are legally enforceable. The shareholders of Beijing Momo are also shareholders of the Company and therefore have no current interest in seeking to act contrary to the contractual arrangements. However, uncertainties in the PRC legal system could limit the Company’s ability to enforce these contractual arrangements and if the shareholders of the VIE were to reduce their interest in the Company, their interests may diverge from that of the Company and that may potentially increase the risk that they would seek to act contrary to the contractual terms, for example by influencing the VIE not to pay the service fees when required to do so.

However, the Company cannot assure that when conflicts of interest arise, the shareholders will act in the best interests of the Company or that conflicts of interests will be resolved in the Company’s favor. Currently, the Company does not have existing arrangements to address potential conflicts of interest the shareholders of the VIE may encounter in their capacity as the beneficial owners and director of the VIE on the one hand, and as beneficial owners and directors or officer of the Company, on the other hand. The Company believes the shareholders of the VIE will not act contrary to any of the contractual arrangements and the Exclusive Call Option Agreement provides the Company with a mechanism to remove the shareholders as the beneficial shareholders of the VIE should they act to the detriment of the Company. The Company relies on the VIE’s shareholders, as directors and officer of the Company, to fulfill their fiduciary duties and abide by laws of the PRC and the Cayman and act in the best interest of the Company. If the Company cannot resolve any conflicts of interest or disputes between the Company and the VIE’s shareholders, the Company would have to rely on legal proceedings, which could result in disruption of its business, and there is substantial uncertainty as to the outcome of any such legal proceedings.

The Company’s ability to control the VIE also depends on the Power of Attorney. Beijing Momo IT and Beijing Momo have to vote on all matters requiring shareholder approval in the VIE. As noted above, the Company believes this power of attorney is legally enforceable but may not be as effective as direct equity ownership.

In addition, if the legal structure and contractual arrangements were found to be in violation of any existing PRC laws and regulations, the PRC government could:

•

revoke the Group’s business and operating licenses;

•

require the Group to discontinue or restrict operations;

•

restrict the Group’s right to collect revenues;

•

block the Group’s websites;

•

require the Group to restructure the operations in such a way as to compel the Group to establish a new enterprise, re-apply for the necessary licenses or relocate our businesses, staff and assets;

•

impose additional conditions or requirements with which the Group may not be able to comply; or

•

take other regulatory or enforcement actions against the Group that could be harmful to the Group’s business.

The imposition of any of these penalties may result in a material and adverse effect on the Group’s ability to conduct the Group’s business. In addition, if the imposition of any of these penalties causes the Group to lose the rights to direct the activities of the VIE or the right to receive their economic benefits, the Group would no longer be able to consolidate the VIE. The Group does not believe that any penalties imposed or actions taken by the PRC government would result in the liquidation of the Company, Beijing Momo IT, or the VIE.

The following consolidated financial statements amounts and balances of the VIE were included in the accompanying consolidated financial statements after the elimination of intercompany balances and transactions as of and for the years ended December 31:


	As of December 31,
	2016		2017
Cash and cash equivalents	$	36,855	$	63,110
Accounts receivable, net of allowance for doubtful accounts of $nil and $90 as of December 31, 2016 and 2017, respectively		36,078		39,597
Amount due from related parties		88		5,143
Prepaid expenses and other current assets		20,613		57,056
Deferred tax assets, current		72		—
Short-term investment		—		1,614

Total current assets		93,706		166,520

Property and equipment, net		1,854		8,080
Intangible assets		—		7,462
Rental deposits		325		1,609
Other non-current assets		2,593		7,685
Long term investments		26,541		43,333
Deferred tax assets, non-current		208		1,062
Goodwill		—		3,401

Total assets		125,227		239,152

Accounts payable		36,812		54,937
Deferred revenue		41,277		64,788
Accrued expenses and other current liabilities		6,632		30,802
Amounts due to related parties		1,510		29
Income tax payable		3,881		11,765

Total current liabilities		90,112		162,321

Deferred tax liabilities, non-current		—		1,866

Total liabilities	$	90,112	$	164,187


	For the years ended December 31,
	2015			2016			2017
Net revenues	$	133,988		$	553,098		$	1,318,271
Net income	$	118,404		$	340,366		$	724,880
Net cash provided by operating activities	$	124,786		$	360,433		$	740,683
Net cash used in investing activities	$	(19,435	)	$	(11,027	)	$	(25,810	)
Net cash provided by financing activities	$	—		$	—		$	73

The unrecognized revenue-producing assets that are held by the VIE are primarily self-developed intangible assets such as domain names, trademark and various licenses which are un-recognized at consolidated balance sheets.

The VIE contributed an aggregate of 100% of the consolidated net revenues for each of the years ended December 31, 2015, 2016 and 2017, respectively. As of the fiscal years ended December 31, 2016 and 2017, the VIE accounted for an aggregate of 16.3% and 18.4%, respectively, of the consolidated total assets, and 66.4% and 62.1%, respectively, of the consolidated total liabilities. The assets that were not associated with the VIE primarily consist of cash and cash equivalents, and term deposits.

There are no consolidated VIE’s assets that are collateral for the VIE’s obligations and can only be used to settle the VIE’s obligations. There are no creditors (or beneficial interest holders) of the VIE that have recourse to the general credit of the Company or any of its consolidated subsidiaries. There are no terms in any arrangements, considering both explicit arrangements and implicit variable interests, that require the Company or its subsidiaries to provide financial support to the VIE. However, if the VIE ever needs financial support, the Company or its subsidiaries may, at its option and subject to statutory limits and restrictions, provide financial support to its VIE through loans to the shareholders of the VIE or entrustment loans to the VIE. Relevant PRC laws and regulations restrict the VIE from transferring a portion of its net assets, equivalent to the balance of its statutory reserve and its share capital, to the Company in the form of loans and advances or cash dividends. Please refer to Note 18 for disclosure of restricted net assets. The Group may lose the ability to use and enjoy assets held by the VIE that are important to the operation of business if the VIE declares bankruptcy or becomes subject to a dissolution or liquidation proceeding.

Significant Accounting Policies

12 Months Ended

Dec. 31, 2017

Accounting Policies [Abstract]

Significant Accounting Policies

2.	SIGNIFICANT ACCOUNTING POLICIES

Basis of presentation

The consolidated financial statements of the Group have been prepared in accordance with the accounting principles generally accepted in the United States of America (“U.S. GAAP”).

Basis of consolidation

The consolidated financial statements of the Group include the financial statements of Momo Inc., its subsidiaries, its VIE and VIE’s subsidiaries. All inter-company transactions and balances have been eliminated upon consolidation.

Use of estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and revenues, cost and expenses in the financial statements and accompanying notes. Significant accounting estimates reflected in the Group’s consolidated financial statements include revenue recognition, the useful lives and impairment of property and equipment, valuation allowance for deferred tax assets, and share-based compensation.

Cash and cash equivalents

Cash and cash equivalents consist of cash on hand and highly liquid investments, which are unrestricted from withdrawal or use, or which have original maturities of three months or less when purchased.

Term deposits

Term deposits consist of bank deposits with an original maturity of over three months.

Accounts receivable

Accounts receivable primarily represents the cash due from third-party application stores and other payment channels and advertising customers, net of allowance for doubtful accounts. The Group makes estimates for the allowance for doubtful accounts based upon its assessment of various factors, including the age of accounts receivable balances, credit quality of third-party application stores and other payment channels and advertising customers, current economic conditions and other factors that may affect their ability to pay. An allowance for doubtful accounts is recorded in the period in which a loss is determined to be probable.

Financial instruments

Financial instruments of the Group primarily consist of cash and cash equivalents, term deposits, accounts receivable, cost method investments, available-for-sale investments, accounts payable, deferred revenue, income tax payable, amount due from related parties and amount due to related parties.

Cash and cash equivalents are recorded at fair value based on the quoted market price in an active market. The carrying values of term deposits, accounts receivable, accounts payable, deferred revenue, income tax payable, amount due from related parties and amount due to related parties approximate their fair values due to short-term maturities. It is not practical to estimate the fair value of the Group’s cost method investments because of the lack of quoted market price and the inability to estimate fair value without incurring excessive costs. Available-for-sale investments are reported at fair value, which is discussed in Note 9.

Foreign currency risk

The Renminbi (“RMB”) is not a freely convertible currency. The State Administration for Foreign Exchange, under the authority of the People’s Bank of China, controls the conversion of RMB into foreign currencies. The value of the RMB is subject to changes in central government policies and to international economic and political developments affecting supply and demand in the China Foreign Exchange Trading System market. Cash and cash equivalents of the Group included aggregate amounts of $245,853 and $632,572 as of December 31, 2016 and 2017, respectively, which were denominated in RMB.

Concentration of credit risk

Financial instruments that potentially expose the Group to concentration of credit risk consist primarily of cash and cash equivalents, term deposits and accounts receivable. The Group places their cash with financial institutions with high-credit ratings and quality.

Third-party application stores and other payment channels accounting for 10% or more of accounts receivables are as follows:


	As of December 31,
	2016			2017
A		40	%		23	%
B		—			21	%
C		15	%		19	%
D		22	%		5	%

No user or advertising customer accounted for 10% or more of accounts receivables for the years ended December 31, 2016 and 2017, respectively.

Concentration of revenue

No user or customer accounted for 10% or more of net revenues for the years ended December 31, 2015, 2016 and 2017, respectively.

Cost method investments

For investee companies over which the Group neither has significant influence nor control through investment in common shares or in-substance common shares and which do not have readily determinable fair value, the Group accounts for the investments under the cost method, and carries the investments at cost and recognizes as income any dividend received from distribution of the investee’s earnings. The Group reviews its cost method investments for impairment whenever events or changes in circumstances indicate that the carrying value may no longer be recoverable. An impairment loss is recognized in earnings equal to the difference between the investment’s cost and its fair value at the balance sheet date of the reporting period for which the assessment is made. The fair value of the investment would then become the new cost basis of the investment.

Equity method investments

The investee companies over which the Group has the ability to exercise significant influence, but does not have a controlling interest are accounted for using the equity method. Significant influence is generally considered to exist when the Group has an ownership interest in the voting stock of the investee between 20% and 50%. Other factors, such as representation in the investee’s Board of Directors, voting rights and the impact of commercial arrangements, are also considered in determining whether the equity method of accounting is appropriate. For the investment in limited partnerships, where the Group holds less than a 20% equity or voting interest, the Group’s influence over the partnership operating and financial policies is determined to be more than minor. Accordingly, the Group accounts for these investments as equity method investments.

Under the equity method of accounting, the affiliated company’s accounts are not reflected within the Group’s consolidated balance sheets and statements of operations; however, the Group’s share of the earnings or losses of the affiliated company is reflected in the caption “share of income on equity method investments” in the consolidated statements of operations.

An impairment change is recorded if the carrying amount of the investment exceeds its fair value and this condition is determined to be other-than-temporary.

The Group estimates the fair value of the investee company based on comparable quoted price for similar investment in active market, if applicable, or discounted cash flow approach which requires significant judgments, including the estimation of future cash flows, which is dependent on internal forecasts, the estimation of long term growth rate of a company’s business, the estimation of the useful life over which cash flows will occur, and the determination of the weighted average cost of capital.

Available-for-sale Investments

For investments in investees’ stocks which are determined to be debt securities, the Group accounts for them as long-term available-for-sale investments when they are not classified as either trading or held-to-maturityinvestments.

Available-for-sale investments are reported at fair value, with unrealized gains and losses recorded in accumulated other comprehensive income (loss) as a component of shareholders’ equity. Realized gains and losses and provision for decline in value judged to be other than temporary, if any, are recognized in the consolidated statements of operations.

The Group continually reviews its available-for-sale investments to determine whether a decline in fair value below the carrying value is other than temporary. The primary factors the Group considers in its determination are the length of time that the fair value of the investment is below the Group’s carrying value; the financial condition, operating performance and the prospects of the available-for-sale investee; and other specific information such as recent financing rounds. If the decline in fair value is deemed to be other than temporary, the carrying value of the available-for-sale investee is written down to fair value. The Group estimated the fair value of these investee companies based on discounted cash flow approach which requires significant judgments, including the estimation of future cash flows, which is dependent on internal forecasts, the estimation of long term growth rate of a company’s business, the estimation of the useful life over which cash flows will occur, and the determination of the weighted average cost of capital.

Property and equipment, net

Property and equipment are stated at cost less accumulated depreciation. Depreciation is calculated on a straight-line basis over the following estimated useful lives:


Office equipment			3-5 years
Computer equipment			3 years
Vehicles			5 years
Leasehold improvement			Shorter of the lease term or estimated useful lives

Intangible assets

Intangible assets acquired through business acquisitions are recognized as assets separate from goodwill if they satisfy either the “contractual-legal” or “separability” criterion. Purchased intangible assets and intangible assets arising from the acquisitions of subsidiaries are recognized and measured at fair value upon acquisition. Separately identifiable intangible assets that have determinable lives continue to be amortized over their estimated useful lives using the straight-line method as follows:


Copyright			1 year
License			3.2-10 years

Impairment of long-lived assets with finite lives

The Group reviews its long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may no longer be recoverable. When these events occur, the Group measures impairment by comparing the carrying value of the long-lived assets to the estimated undiscounted future cash flows expected to result from the use of the assets and their eventual disposition. If the sum of the expected undiscounted cash flow is less than the carrying amount of the assets, the Group would recognize an impairment loss based on the fair value of the assets.

Goodwill

Goodwill represents the excess of the purchase consideration over the fair value of the identifiable tangible and intangible assets acquired and liabilities assumed of the acquired entity as a result of the Company’s acquisitions of interests in its subsidiaries. Goodwill is not amortized but is tested for impairment on an annual basis, or more frequently if events or changes in circumstances indicate that it might be impaired. The Company has an option to first assess qualitative factors to determine whether it is necessary to perform the two-step quantitative goodwill impairment test. In the qualitative assessment, the Company considers primary factors such as industry and market considerations, overall financial performance of the reporting unit, and other specific information related to the operations. Based on the qualitative assessment, if it is more likely than not that the fair value of each reporting unit is less than the carrying amount, the quantitative impairment test is performed.

In performing the two-step quantitative impairment test, the first step compares the fair values of each reporting unit to its carrying amount, including goodwill. If the fair value of each reporting unit exceeds its carrying amount, goodwill is not considered to be impaired and the second step will not be required. If the carrying amount of a reporting unit exceeds its fair value, the second step compares the implied fair value of goodwill to the carrying value of a reporting unit’s goodwill. The implied fair value of goodwill is determined in a manner similar to accounting for a business combination with the allocation of the assessed fair value determined in the first step to the assets and liabilities of the reporting unit. The excess of the fair value of the reporting unit over the amounts assigned to the assets and liabilities is the implied fair value of goodwill. This allocation process is only performed for the purposes of evaluating goodwill impairment and does not result in an entry to adjust the value of any assets or liabilities. Application of a goodwill impairment test requires significant management judgment, including the identification of reporting units, assigning assets, liabilities and goodwill to reporting units, and determining the fair value of each reporting unit.

Fair value

Fair value is the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining the fair value measurements for assets and liabilities required or permitted to be recorded at fair value, the Group considers the principal or most advantageous market in which it would transact and it considers assumptions that market participants would use when pricing the asset or liability.

Authoritative literature provides a fair value hierarchy that requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. An asset or liability categorization within the fair value hierarchy is based upon the lowest level of input that is significant to the fair value measurement as follows:

Level 1

Level 1 applies to assets or liabilities for which there are quoted prices in active markets for identical assets or liabilities.

Level 2

Level 2 applies to assets or liabilities for which there are inputs other than quoted prices included within Level 1 that are observable for the assets or liabilities such as quoted prices for similar assets or liabilities in active markets; quoted prices for identical assets or liabilities in markets with insufficient volume or infrequent transactions (less active markets); or model-derived valuations in which significant inputs are observable or can be derived principally from, or corroborated by, observable market data.

Level 3

Level 3 applies to assets or liabilities for which there are unobservable inputs to the valuation methodology that are significant to the measurement of the fair value of the assets or liabilities.

Revenue recognition

The Group recognizes revenue when a persuasive evidence of an arrangement exists, delivery has occurred, the sales price is fixed or determinable, and collectability is reasonably assured. The Group principally derives its revenue from live video service, value-added services, mobile marketing services, mobile games and other services.

(a)

Live video service

The Group provides live video service whereby users can enjoy live performances and interact with the broadcasters for free, and have the option of purchasing in-show virtual items. Broadcasters can either host the performance on their own or join a broadcaster agency. Users purchase virtual gifts from the Group and present them to broadcasters to show their support. The Group determines the virtual items price and generates revenue from sales of virtual gifts upon purchase. Under the arrangements with broadcasters or broadcaster agencies, the Group shares with them a portion of the revenues derived from the sales of virtual gifts. Revenues derived from the sale of virtual gifts are recorded on a gross basis as the Group has determined that it acts as the principal to fulfill all obligations related to the live video services. The portion paid to broadcasters and/or broadcaster agencies is recognized as cost of revenues.

Net revenues of $1,231, $376,925 and $1,102,592 were recognized for live video services for the years ended December 31, 2015, 2016 and 2017, respectively.

(b)

Value-added services

Value-added services revenues include membership subscription revenue and virtual gift service revenue. Membership subscription is a service package which enables members to enjoy additional functions and privileges. The contract period for the membership subscription ranges from one month to one year. All membership subscription is nonrefundable. The Group collects membership subscription in advance and records it as deferred revenue. Revenue is recognized ratably over the contract period for the membership subscription services.

Virtual gift service was launched in 2016 to enhance users’ experience of interaction and social networking with each other. Users purchase virtual gifts and send the virtual gifts simultaneously to other users, while the Group shares with them a portion of the revenues derived from the sales of virtual gifts. Revenues derived from the sale of virtual gifts are recorded on a gross basis as the Group has determined that it acts as the principal to fulfill all obligations related to the virtual gift services. The portion paid to gift recipients is recognized as cost of revenues.

Net revenues of $58,462, $67,603 and $103,139 were recognized for value-added services for the years ended December 31, 2015, 2016 and 2017, respectively.

(c)

Mobile marketing

The Group provides advertising and marketing solutions to customers for promotion of their brands and conduction of effective marketing activities through its mobile application.

Display-based mobile marketing services

For display-based online advertising services such as banners and location-based advertising on the mobile applications, the Group recognizes revenue ratably over the period that the advertising is provided commencing on the date the customer’s advertisement is displayed, or on the number of times that the advertisement has been displayed for cost per thousand impressions advertising arrangements.

Performance-based mobile marketing services

The Group enables advertising customers to place link on its mobile platform on a pay-for-effectiveness basis, which is referred to as the cost for performance model. The Group charges fees to advertising customers based on the effectiveness of advertising links, which is measured by active clicks. Revenue is estimated by the Group based on its internal data, which is confirmed with respective customers, or is recognized based on a fixed unit price.

The Group’s revenue transactions are based on standard business terms and conditions, which are recognized net of agency rebates, if applicable.

Net revenues of $38,885, $66,339 and $76,178 were recognized for mobile marketing for the years ended December 31, 2015, 2016 and 2017, respectively.

(d)

Mobile games

The Group publishes both licensed mobile games developed by third-party game developers and its self-developed games to the game players through its mobile application.

Licensed mobile games

The Group generates revenue from offering services of mobile games developed by third-party game developers. All of the licensed games can be accessed and played by game players directly through the Group’s mobile game platform. The Group primarily views the game developers to be its customers and considers its responsibility under its agreements with the game developers to be promotion of the game developers’ games. The Group generally collects payments from game players in connection with the sale of in-game currencies and remits certain agreed-upon percentages of the proceeds to the game developers and records revenue net of remittances. Purchases of in-game currencies are not refundable after they have been sold unless there is unused in-game currencies at the time a game is discontinued. Typically, a game will only be discontinued when the monthly revenue generated by a game becomes consistently insignificant. The Group does not currently expect to pay any material cash refunds to game players or game developers in connection with a discontinued game.

Licensed mobile games - Non-exclusive mobile games services

The Group enters into non-exclusive agreements with the game developers and offers the Group’s mobile game platform for the mobile games developed by the game developers. The Group has determined that it has no additional performance obligation to the developers or game players upon players’ completion of the corresponding in-game purchase. Therefore, revenues from the sale of in-game currencies are primarily recorded net of remittances to game developers and commission fees made to third-party application stores and other payment channels and deferred until the estimated consumption date by individual game (i.e., the estimated date in-game currencies are consumed within the game), which is typically within a short period of time ranging from zero to three days after the purchase of the in-game currencies.

Licensed mobile games - Exclusive mobile games services

The Group enters into exclusive agreements with the game developers and provides the Group’s mobile game platform for the mobile games developed by the game developers. Under the exclusive agreements, the players can access to the games only through the Group’s platform. The Group has determined that it is obligated to provide mobile games services to game players who purchased virtual items to gain an enhanced game-playing experience over an average period of player relationship. Hence, the Group believes that its performance for, and obligation to, the game developers correspond to the game developers’ services to the players. The Group does not have access to the data on the consumption details and the types of virtual items purchased by the game players. Therefore, the Group cannot estimate the economic life of the virtual item. However, the Group maintains data of when a particular player purchases the virtual items and logs into the games. The Group has adopted a policy to recognize revenues net of remittances to game developers and commission fees made to third-party application stores and other payment channels over the estimated period of player relationship on a game-by-game basis. As of December 31, 2016 and 2017, the Group operated six and six games under exclusive arrangements and the estimated periods of the player relationship is in a range of 20 to 99 and 20 to 101 days, respectively.

Self-developed mobile game

In February 2015, the Group launched one self-developed game on its platform and started to generate revenues by in-game sales of virtual item. The Group has determined that an obligation exists to the players who purchased the virtual items to gain an enhanced game-playing experience over the playing period of the paying players, and accordingly, recognized the revenues ratably over the estimated average period of player relationship starting from the point in time when the players purchase the virtual items, and all other revenue recognition criteria are met. As of December 31, 2016 and 2017, the Group operated six and eight self-developed mobile games and the estimated periods of the player relationship is in a range of 20 to 110 days and 56 to 79 days, respectively.

Revenues derived from the self-developed game are recorded on a gross basis as the Group acts as a principal to fulfill all obligations related to the mobile game operation. Commission fees paid to third-party application stores and other payment channels are recorded as cost of revenues.

Net revenues of $31,082, $35,453 and $35,619 were recognized for mobile games for the years ended December 31, 2015, 2016 and 2017, respectively.

(e)

Other service

Other service primarily includes Duobao service and paid emoticons.

Advertising barter transactions

The Group engages in barter transactions where it trades advertising resources with certain third parties for other advertising resources and goods. The Group recognizes revenues and expenses at fair value only if the fair value of the services exchanged in the transaction is determinable based on the Group’s own historical practice of receiving cash or other consideration that is readily convertible to a known amount of cash for similar advertising resources from customers unrelated to the party in the barter transaction. When the fair value of the transactions is not determinable due to the lack of the Group’s similar historical practice, the advertising barter transactions shall be recorded based on the carrying amount of the advertising surrendered which is the estimated cost to be incurred, or the fair value of the assets received. Advertising barter transactions were insignificant for all the years presented.

Deferred revenue

Deferred revenue primarily includes cash received in advance from users and advertising customers. The unused cash balances remaining in users’ and advertising customers’ accounts are recorded as a liability. Deferred revenue related to prepayments from users and advertising customers will be recognized as revenue when all of the revenue recognition criteria are met.

Cost of revenues

Cost of revenues consist of expenditures incurred in the generation of the Group’s revenues, including but not limited to revenue sharing with the broadcasters, broadcaster agencies related to live video service and virtual gift recipients, commission fee paid to third-party application stores and other payment channels except for those paid related to licensed mobile games which are recorded net of revenue, bandwidth costs, salaries and benefits paid to employee, short messaging service charges and depreciation. These costs are expensed as incurred except for the direct and incremental platform commission fees to third-party application stores and other payment channels which are deferred in “Prepaid expenses and other current assets” on the consolidated balance sheets. The deferred platform commissions are recognized in the consolidated statements of operations in “Cost of revenues” in the period in which the related revenues are recognized.

Government subsidies

For the government subsidies not subject to further performance obligations or future returns, the Group records the amounts as other income when received from local government authority. Whereas for the government subsidies with certain future performance obligations, the Group recognizes those as liabilities when received until the performances obligations have been met at which time, those are recognized as other income. Government subsidies recorded as other income amounted to $nil, $293 and $20,977 for the years ended December 31, 2015, 2016 and 2017.

Research and development expenses

Research and development expenses primarily consist of (i) salaries and benefits for research and development personnel, and (ii) technological service fee, office rental and depreciation expenses associated with the research and development activities. The Group’s research and development activities primarily consist of the research and development of new features for its mobile platform and its self-developed mobile games. The Group has expensed all research and development expenses when incurred.

Value added taxes (“VAT”)

Entities that are VAT general taxpayers are allowed to offset qualified input VAT paid to suppliers against their output VAT liabilities. Net VAT balance between input VAT and output VAT is recorded in accrued expenses and other current liabilities on the consolidated balance sheets. VAT is also reported as a deduction to revenue when incurred and amounted to $16,951, $55,353 and $120,256 for the years ended December 31, 2015, 2016 and 2017, respectively.

Income taxes

Current income taxes are provided for in accordance with the laws of the relevant tax authorities. Deferred income taxes are recognized when temporary differences exist between the tax bases of assets and liabilities and their reported amounts in the consolidated financial statements. Net operating loss carry forwards and credits are applied using enacted statutory tax rates applicable to future years. Deferred tax assets are reduced by a valuation allowance when, in the opinion of management, it is more-likely-than-not that a portion of or all of the deferred tax assets will not be realized. The components of the deferred tax assets and liabilities are individually classified as current and non-current based on their characteristics before 2016. The Group adopted ASU 2015-17 in the first quarter of 2017 and classified all deferred taxes assets and liabilities as noncurrent as of December 31, 2017. The Group did not retrospectively apply the changes to the prior years.

The impact of an uncertain income tax position on the income tax return is recognized at the largest amount that is more-likely than- not to be sustained upon audit by the relevant tax authority. An uncertain income tax position will not be recognized if it has less than a 50% likelihood of being sustained. Interest and penalties on income taxes will be classified as a component of the provisions for income taxes. The Group recognized income tax expense which amounted to $92, $5,136 and $65,980 for the years ended December 31, 2015, 2016 and 2017, respectively.

Foreign currency translation

The functional and reporting currency of the Group is the United States dollar (“U.S. dollar”). The financial records of the Group’s subsidiaries, VIE and VIE’s subsidiaries located in the PRC are maintained in their local currencies, the RMB, which are also the functional currencies of these entities.

Monetary assets and liabilities denominated in currencies other than the functional currency are translated into the functional currency at the rates of exchange in place at the balance sheet date. Transactions in currencies other than the functional currency during the year are converted into the functional currency at the applicable rates of exchange prevailing when the transactions occurred. Transaction gains and losses are recognized in the consolidated statement of operations.

The Group’s entities with functional currency of RMB, translate their operating results and financial positions into the U.S. dollar, the Group’s reporting currency. Assets and liabilities are translated using the exchange rates in effect on the balance sheet date. Revenues, expenses, gains and losses are translated using the average rate for the year. Translation adjustments are reported as cumulative translation adjustments and are shown as a separate component of comprehensive loss.

Operating leases

Leases where the rewards and risks of ownership of assets primarily remain with the lessor are accounted for as operating leases. Payments made under operating leases are charged to the consolidated statements of operations on a straight-line basis over the lease periods.

Advertising expenses

The Group expenses advertising expenses as incurred. Total advertising expenses incurred were $27,793, $55,188 and $153,425 for the years ended December 31, 2015, 2016 and 2017, respectively, and have been included in sales and marketing expenses in the consolidated statements of operations.

Comprehensive income

Comprehensive income includes net income, unrealized gain or loss on available-for-sale investments and foreign currency translation adjustments. Comprehensive income is reported in the consolidated statements of comprehensive income.

Share-based compensation

Share-based payment transactions with employees and executives are measured based on the grant date fair value of the equity instrument issued and recognized as compensation expense net of a forfeiture rate on a straight-line basis, over the requisite service period, with a corresponding impact reflected in additional paid-in capital.

Share awards issued to consultants are measured at fair value at the earlier of the commitment date or the date the services are completed and recognized over the period the services are provided.

The estimate of forfeiture rate will be adjusted over the requisite service period to the extent that actual forfeiture rate differs, or is expected to differ, from such estimates. Changes in estimated forfeiture rate will be recognized through a cumulative catch-up adjustment in the period of change.

Changes in the terms or conditions of share options are accounted as a modification under which the Group calculates whether there is any excess of the fair value of the modified option over the fair value of the original option immediately before its terms are modified, measured based on the share price and other pertinent factors at the modification date. For vested options, the Group recognizes incremental compensation cost in the period of the modification occurred and for unvested options, the Group recognizes, over the remaining requisite service period, the sum of the incremental compensation cost and the remaining unrecognized compensation cost for the original award on the modification date.

Earnings per share

Basic earnings per ordinary share is computed by dividing net income attributable to ordinary shareholders by the weighted average number of ordinary shares outstanding during the period.

The Group determined that the nonvested restricted shares are participating securities as the holders of the nonvested restricted shares have a nonforfeitable right to receive dividends with all ordinary shares but the nonvested restricted shares do not have a contractual obligation to fund or otherwise absorb the Group’s losses. Accordingly, the Group uses the two-class method whereby undistributed net income is allocated on a pro rata basis to the ordinary shares and nonvested restricted shares to the extent that each class may share in income for the period; whereas the undistributed net loss for the period is allocated to ordinary shares only because the nonvested restricted shares are not contractually obligated to share the loss.

Diluted earnings per ordinary share reflect the potential dilution that could occur if securities were exercised or converted into ordinary shares. The Group had share options and restricted share units, which could potentially dilute basic earnings per share in the future. To calculate the number of shares for diluted earnings per ordinary share, the effect of the share options and restricted share units is computed using the treasury stock method.

Recent accounting pronouncement adopted

In November 2015, the FASB issued ASU No. 2015-17, Balance Sheet Classification of Deferred Taxes (“ASU 2015-17”). ASU 2015-17 simplifies the presentation of deferred taxes by requiring deferred tax assets and liabilities be classified as noncurrent on the consolidated balance sheet. The Company prospectively adopted ASU 2015-17 effective January 1, 2017. Therefore, prior periods have not been adjusted to reflect this adoption. The adoption of ASU 2015-17 did not have a significant impact on the Company’s consolidated results of operations, financial position or cash flows.

Recent accounting pronouncements not yet adopted

In May 2014, the FASB issued, ASU 2014-09, “Revenue from Contracts with Customers (Topic 606)”. The guidance substantially converges final standards on revenue recognition between the FASB and the International Accounting Standards Board providing a framework on addressing revenue recognition issues and, upon its effective date, replaces almost all exiting revenue recognition guidance, including industry-specific guidance, in current U.S. generally accepted accounting principles.

The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. To achieve that core principle, an entity should apply the following steps:

•

Step 1: Identify the contract (s) with a customer.

•

Step 2: Identify the performance obligations in the contract.

•

Step 3: Determine the transaction price.

•

Step 4: Allocate the transaction price to the performance obligations in the contract.

•

Step 5: Recognize revenue when (or as) the entity satisfies a performance obligation.

In August 2015, FASB issued its final standard formally amending the effective date of the new revenue recognition guidance. The amendments in this ASU are effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period. Earlier application is permitted only as of annual reporting periods beginning after December 15, 2016, including interim reporting periods within that reporting period. The new revenue guidance may be applied retrospectively to each prior period presented or retrospectively with the cumulative effect recognized as of the date of adoption.

In November 2017, the FASB issued a new pronouncement, ASU 2017-14, which amends the Codification to incorporate SEC Staff Accounting Bulletin (SAB) No. 116 and SEC Interpretive Release on Vaccines for Federal Government Stockpiles (SEC Release No. 33-10403) that bring existing SEC staff guidance into conformity with the FASB’s adoption of and amendments to ASC Topic 606, Revenue from Contracts with Customers.

The Group expects to adopt ASU 2014-09 under the modified retrospective method in the first quarter of 2018. The Group has substantially completed a review of the impacts of the new standard to its existing portfolio of customer contracts. The Group does not believe the adoption of ASU 2014-09 would have a material effect on its current revenue recognition policies. However, certain additional financial statement disclosure requirements are mandated by the new standard including disclosure of contract assets and contract liabilities as well as a disaggregated view of revenue.

In January, 2016, the FASB issued a new pronouncement ASU 2016-01 which is intended to improve the recognition and measurement of financial instruments. The ASU affects public and private companies, not-for-profitorganizations, and employee benefit plans that hold financial assets or owe financial liabilities.

The new guidance makes targeted improvements to existing U.S. GAAP by:

•

Requiring equity investments (except those accounted for under the equity method of accounting, or those that result in consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income;

•

Requiring public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes;

•

Requiring separate presentation of financial assets and financial liabilities by measurement category and form of financial asset (i.e., securities or loans and receivables) on the balance sheet or the accompanying notes to the financial statements;

•

Eliminating the requirement to disclose the fair value of financial instruments measured at amortized cost for organizations that are not public business entities;

•

Eliminating the requirement for public business entities to disclose the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet; and

•

Requiring a reporting organization to present separately in other comprehensive income the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk (also referred to as “own credit”) when the organization has elected to measure the liability at fair value in accordance with the fair value option for financial instruments.

The new guidance is effective for public companies for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. The new guidance permits early adoption of the own credit provision. Adoption of the amendment must be applied by means of a cumulative-effect adjustment to the balance sheet as of the beginning of the fiscal year of adoption, except for amendments related to equity instruments that do not have readily determinable fair values which should be applied prospectively. The Group is in the process of evaluating the impact of adoption of this guidance on its consolidated financial statements.

In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842). The guidance supersedes existing guidance on accounting for leases with the main difference being that operating leases are to be recorded in the statement of financial position as right-of-use assets and lease liabilities, initially measured at the present value of the lease payments. For operating leases with a term of 12 months or less, a lessee is permitted to make an accounting policy election not to recognize lease assets and liabilities. For public business entities, the guidance is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early application of the guidance is permitted. In transition, entities are required to recognize and measure leases at the beginning of the earliest period presented using a modified retrospective approach. The Group is currently evaluating the impact the adoption of ASU No. 2016-02 will have on its consolidated financial statements, but the Group expects that most existing operating lease commitments will be recognized as operating lease obligations and right-of-use assets as a result of this adoption.

In January 2017, the FASB issued ASU 2017-04: Intangibles—Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment. To simplify the subsequent measurement of goodwill, the Board eliminated Step 2 from the goodwill impairment test. Under the amendments in this Update, an entity should perform its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. An entity should apply the amendments in this Update on a prospective basis. An entity is required to disclose the nature of and reason for the change in accounting principle upon transition. A public business entity that is a SEC filer should adopt the amendments in this Update for its annual or any interim goodwill impairment tests in fiscal years beginning after December 15, 2019. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The Group is in the process of evaluating the impact of the Update on its consolidated financial statements.

In May, 2017, FASB issued a new pronouncement, ASU 2017-09, which amends the scope of modification accounting for share-based payment arrangements. The ASU provides guidance on the types of changes to the terms or conditions of share-based payment awards to which an entity would be required to apply modification accounting under ASC 718. Specifically, an entity would not apply modification accounting if the fair value, vesting conditions, and classification of the awards are the same immediately before and after the modification. The new accounting guidance is effective for annual reporting periods, including interim periods within those annual reporting periods, beginning after December 15, 2017. Early adoption is permitted, including adoption in any interim period. The Group is in the process of assessing the impact on its consolidated financial statements from the adoption of the new guidance.

Accounts Receivable, Net

12 Months Ended

Dec. 31, 2017

Receivables [Abstract]

Accounts Receivable, Net

3.	ACCOUNTS RECEIVABLE, NET

Accounts receivable, net consisted of the following:


	As of December 31,
	2016		2017
Accounts receivable	$	36,078	$	39,687
Less: allowance for doubtful accounts		—		(90)

Accounts receivable, net	$	36,078	$	39,597

- Definition

The entire disclosure for claims held for amounts due a entity, excluding financing receivables. Examples include, but are not limited to, trade accounts receivables, notes receivables, loans receivables. Includes disclosure for allowance for credit losses.

+ References + Details

Prepaid Expenses and Other Current Assets

12 Months Ended

Dec. 31, 2017

Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]

Prepaid Expenses and Other Current Assets

4.	PREPAID EXPENSES AND OTHER CURRENT ASSETS

Prepaid expenses and other current assets consisted of the following:


	As of December 31,
	2016		2017
Deposit at a third-party payment channel (i)	$	4,845	$	29,239
Advance to suppliers (ii)		5,331		21,521
Interest receivable		4,821		8,441
Prepaid income tax and other expenses		2,964		8,069
Deferred platform commission cost		4,571		4,292
Input VAT (iii)		2,968		3,714
Game promotions fees paid on behalf of game developers		2,250		2,742
Advance to game developers		1,550		924
Others		3,292		3,775

	$	32,592	$	82,717

(i)

Deposit at a third party payment channel is the cash deposited in a third party payment channel by the Group for the broadcasters to withdraw their revenue sharing and the customer payment to the Group’s account through a third party payment channel.

(ii)

Advance to suppliers were primarily for advertising fees and live video broadcasting service fees.

(iii)

Input VAT mainly occurred from the purchasing of goods for other services, property and equipment and advertising activities. It is subject to verification by related tax authorities before offsetting the VAT output.

Long Term Investments

12 Months Ended

Dec. 31, 2017

Investments Schedule [Abstract]

Long Term Investments

5.	LONG TERM INVESTMENTS


	As of December 31,
	2016		2017
Equity method investments
Jingwei Chuangteng (Hangzhou) L.P. (i)	$	4,191	$	7,419
Beijing Autobot Venture Capital L.P. (ii)		6,736		8,478
Hangzhou Aqua Ventures Investment Management L.P. (iii)		9,187		12,986
Others (iv)		2,718		3,188

Cost method investments
Hunan Qindao Cultural Spread Ltd. (v)		—		4,611
Others (iv)		1,834		7,655

Available-for-sale investments
Xish International Limited (vi)		4,386		—
Hunan Qindao Cultural Spread Ltd. (v)		2,880		—

	$	31,932	$	44,337

The Group performed impairment analysis for equity method investments and cost method investments. Impairment loss of $nil, $186 and $nil was recorded for equity method investments during the years ended December 31, 2015, 2016 and 2017, respectively. Impairment loss of $nil, $965 and $nil was recorded for cost method investments during the years ended December 31, 2015, 2016 and 2017, respectively.

(i)

On January 9, 2015, the Group entered into a partnership agreement to subscribe partnership interest, as a limited partner, in Jingwei Chuangteng (Hangzhou) L.P. (“Jingwei”). According to the partnership agreement, the Group committed to subscribe 4.9% partnership interest in Jingwei for $4,744, which had been paid as of December 31, 2017. Due to Jingwei’s further rounds of financing, the Group’s partnership interest was diluted to 2.4% as of December 31, 2016 and 2017. The Group recognized its share of partnership profit in Jingwei of $366, $633 and $1,717 during the year ended December 31, 2015, 2016 and 2017, respectively.

(ii)

On February 13, 2015, the Group entered into a partnership agreement to subscribe partnership interest, as a limited partner, in Beijing Autobot Venture Capital L.P. (“Autobot”). According to the partnership agreement, the Group committed to subscribe 31.9% partnership interest in Autobot for $4,823. Autobot had further rounds of financing, of which the Group subscribed for $1,529. Due to Autobot’s further round of financing, the Group’s partnership interest was diluted to 26.7% as of December 31, 2016 and 2017. The committed subscription and further round of financing subscription amount, $6,352, was paid as of December 31, 2016. The Group recognized its share of partnership profit in Autobot of $274, $771 and $1,239 during the year ended December 31, 2015, 2016 and 2017, respectively.

(iii)

On August 18, 2015, the Group entered into a partnership agreement to subscribe partnership interest, as a limited partner, in Hangzhou Aqua Ventures Investment Management L.P. (“Aqua”). According to the partnership agreement, the Group committed to subscribe 42.7% partnership interest for $7,930. The committed subscription amount had been fully paid as of December 31, 2016. The Group recognized its share of partnership profit in Aqua of $89, $2,134 and $3,088 during the years ended December 31, 2015, 2016 and 2017, respectively.

(iv)

Others represent equity method investments or cost method investments that are individually insignificant.

(v)

On June 8, 2016, the Group entered into a share purchase agreement to acquire 16.0% preferred shares of Hunan Qindao Cultural Spread Ltd. (“Qindao”) for a total consideration of $4,441, which was fully paid off as of December 31, 2017. The investment was classified as available-for-sale security as the Group determined that the preferred shares were debt securities due to the redemption option available to the investor and measured the investment subsequently at fair value. No unrealized holding gains was reported in other comprehensive income for the year ended December 31, 2016. On July 7, 2017, the Group signed a supplemental agreement with Qindao to waive the redemption right. The investment was reclassified to cost method investment as a result of the supplemental agreement. The Group recorded $nil of accumulated unrealized holding gain through earnings.

(vi)

On January 21, 2016, the Group entered into a preferred share subscription agreement to acquire 17.3% equity of Xish International Limited (“Xish”) for a total consideration of $9,000, which had been paid as of December 31, 2016. The investment was classified as available-for-sale security as the Group determined that the preferred shares were debt securities due to the redemption option available to the investor and measured the investment subsequently at fair value. The Group recognized an impairment loss of $4,614 and $4,386 during the year ended December 31, 2016 and 2017, respectively. Please refer to Note 9 for additional information on the fair value measurement related to the impairment loss.

Property and Equipment, Net

12 Months Ended

Dec. 31, 2017

Property, Plant and Equipment [Abstract]

Property and Equipment, Net

6.	PROPERTY AND EQUIPMENT, NET

Property and equipment, net consisted of the following:


	As of December 31,
	2016			2017
Computer equipment	$	23,763		$	45,580
Office equipment		4,370			12,214
Vehicles		31			189
Leasehold improvement		2,800			10,366
Less: accumulated depreciation		(18,844	)		(30,566	)
Exchange difference		1,812			1,979

		13,932		$	39,762

Depreciation expenses charged to the consolidated statements of operations for the years ended December 31, 2015, 2016 and 2017 were $6,646, $8,404 and $11,722 respectively.

Intangible Assets, Net

12 Months Ended

Dec. 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible Assets, Net

7.	INTANGIBLE ASSETS, NET

Intangible assets, net consisted of the following:


	As of December 31,
	2017
Licenses*	$	8,059
Game copyright		333
Less: accumulated amortization and impairment		(905	)
Exchange difference		(25	)

Net book value	$	7,462

* Licenses mainly consist of the Internet Audio/Video Program Transmission License, which is a requisite permit according to government regulations for the Group’s business operation such as live video service.

Amortization expenses and impairment loss charged to the consolidated statements of operations for the years ended December 31, 2015, 2016 and 2017 were $nil, $nil and $905 respectively.

The estimated aggregate amortization expenses for each of the five succeeding fiscal years and thereafter are as follows:


For the year ended December 31,	Amounts
2018	$	881
2019		881
2020		881
2021		774
2022		771
Thereafter		3,274

	$	7,462

- Definition

The entire disclosure for the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain (loss) on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss.

+ References + Details

Accrued Expenses and Other Current Liabilities

12 Months Ended

Dec. 31, 2017

Payables and Accruals [Abstract]

Accrued Expenses and Other Current Liabilities

8.	ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES

Accrued expenses and other current liabilities consisted of the following:


	As of December 31,
	2016		2017
Accrued payroll and welfare	$	18,982	$	34,523
Payable for advertisement		9,871		18,783
Balance of users’ virtual accounts		779		14,175
Other tax payables		4,694		9,457
Accrued professional services fee		1,438		3,417
VAT payable		1,919		1,543
Others		2,282		5,911

Total	$	39,965	$	87,809

Fair Value

12 Months Ended

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Fair Value

9.	FAIR VALUE

Measured on recurring basis

The Group measures its financial assets and liabilities including cash and cash equivalents and available-for-sale investments at fair value on a recurring basis as of December 31, 2016 and 2017. Cash and cash equivalents are classified within Level 1 of the fair value hierarchy because they are valued based on the quoted market price in an active market. Available-for-sale investments are debt securities and are measured at fair value on a recurring basis with changes in fair value recorded in unrealized holding gains and losses reported in other comprehensive income.

As of December 31, 2016 and 2017, information about inputs for the fair value measurements of the Group’s assets that are measured at fair value on a recurring basis in periods subsequent to their initial recognition is as follows:


	Fair Value Measurement as of December 31,
Description	2016		Quoted Prices in Active Market for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
			(Level 1)		(Level 2)		(Level 3)
Cash and cash equivalents	$	257,564	$	257,564		—	$	—
Available-for-sale investments		7,266		—		—		7,266

Total	$	264,830	$	257,564		—	$	7,266

	Fair Value Measurement as of December 31,
Description	2017		Quoted Prices in Active Market for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
			(Level 1)		(Level 2)		(Level 3)
Cash and cash equivalents	$	685,827	$	685,827		—	$	—

Total	$	685,827	$	685,827		—	$	—

The Group measured the fair value of its available for sales investments using the income approach and consider those as Level 3 measurement because the Group used unobservable inputs to determine their fair values. Specifically, the Group estimates the fair value of these investments based on the discounted cash flow approach which requires significant judgments, including the estimation of future cash flows, which is dependent on internal forecasts, the estimation of long term growth rate of a company’s business, the estimation of the useful life over which cash flows will occur, and the determination of the weighted average cost of capital. Significant increases (decreases) in any of those inputs in isolation would result in a significantly lower (higher) fair value measurement.

Additional information about the reconciliation of the fair value measurement of available-for-sale investments using significant unobservable inputs (level 3) on a recurring basis are is as follows:


Balance as of December 31, 2016	$	7,266
Purchase		1,458
Other-than-temporary loss recognized		(4,386	)
Reclassification to cost method investment (i)		(4,611	)
Foreign exchange difference		273

Balance as of December 31, 2017	$	—

(i)

The investment in Qindao was reclassified from available-for-sale investment to cost method investment as of result of the waiver of redemption right in July 2017. Please refer to Note 5 for additional information on the reclassification.

Measured on nonrecurring basis

The Group measures its long-term investments (excluding long-term available for sale investments) at fair value on a nonrecurring basis whenever events or changes in circumstances indicate that the carrying value may not be recoverable. As of December 31, 2016 and 2017, the Group performed an impairment test on its cost and equity method investees and recorded an impairment loss of $1,151 and $nil, respectively.

Such impairments are considered level 3 fair value measurements because the Group used unobservable inputs such as the management projection of discounted future cash flow and the discount rate.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Income Taxes

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Income Taxes

10.

INCOME TAXES

Cayman

In July 2014, the Company was redomiciled in the Cayman Islands as an exempted company registered under the laws of the Cayman Islands. Under the current laws of the Cayman Islands, it is not subject to tax on either income or capital gain.

BVI

Momo BVI is a tax-exempted company incorporated in the BVI.

The United States (“US”)

Momo US is incorporated in the US and is subject to state income tax and federal income tax at different tax rates, depending upon taxable income levels. Momo US did not have taxable income and no income tax expense was provided for the year ended December 31, 2017.

Hong Kong

Momo HK was established in Hong Kong and is subject to Hong Kong Profits Tax at 16.5% on its profits of business carried on in Hong Kong.

PRC

In August 2014, Beijing Momo IT was qualified as a software enterprise. As such, Beijing Momo IT will be exempt from income taxes for two years beginning in its first profitable year which was from 2015 to 2016 followed by a tax rate of 12.5% for the succeeding three years which is from 2017 to 2019.

As of December 31, 2017, Chengdu Momo was in the process of filing the western China development enterprise status. The Group believes Chengdu Momo will most likely be qualified as western China development enterprise and accordingly be entitled to a preferential income tax rate of 15% in the year 2017. As a result, the Group applied 15% to determine the tax liabilities for Chengdu Momo.

The other entities incorporated in the PRC are subject to an enterprise income tax at a rate of 25%.

Since January 1, 2011, the relevant tax authorities of the Group’s subsidiaries have not conducted a tax examination on the Group’s PRC entities. In accordance with relevant PRC tax administration laws, tax years from 2014 to 2016 of the Group’s PRC subsidiary, VIE and VIE’s subsidiaries, remain subject to tax audits as of December 31, 2017, at the tax authority’s discretion.

Under the Enterprise Income Tax Law (the “EIT Law”) and its implementation rules which became effective on January 1, 2008, dividends generated after January 1, 2008 and payable by foreign-invested enterprise in the PRC to its foreign investors who are non-resident enterprises are subject to a 10% withholding tax, unless any such foreign investor’s jurisdiction of incorporation has a tax treaty with PRC that provides for a different withholding arrangement. Under the taxation arrangement between the PRC and Hong Kong, a qualified Hong Kong tax resident which is the “beneficial owner” and directly holds 25% or more of the equity interest in a PRC resident enterprise is entitled to a reduced withholding tax rate of 5%. Cayman, where the Company is incorporated, does not have a tax treaty with PRC.

Uncertainties exist with respect to how the current income tax law in the PRC applies to the Group’s overall operations, and more specifically, with regard to tax residency status. The EIT Law includes a provision specifying that legal entities organized outside of the PRC will be considered residents for Chinese income tax purposes if the place of effective management or control is within the PRC. The implementation rules to the EIT Law provide that non-resident legal entities will be considered China residents if substantial and overall management and control over the manufacturing and business operations, personnel, accounting, properties, etc., occurs within the PRC. Despite the present uncertainties resulting from the limited PRC tax guidance on the issue, the Group does not believe that the legal entities organized outside of the PRC within the Group should be treated as residents for EIT law purposes. If the PRC tax authorities subsequently determine that the Company and its subsidiaries registered outside the PRC should be deemed resident enterprises, the Company and its subsidiaries registered outside the PRC will be subject to the PRC income taxes, at a rate of 25%.

If any entity within the Group that is outside the PRC were to be a non-resident for PRC tax purposes dividends paid to it out of profits earned after January 1, 2008 would be subject to a withholding tax at a rate of 10%, subject to reduction by an applicable tax treaty with the PRC.

Aggregate undistributed earnings of the Company’s subsidiaries located in the PRC that are available for distribution at December 31, 2017 are considered to be indefinitely reinvested and accordingly, no provision has been made for the Chinese dividend withholding taxes that would be payable upon the distribution of those amounts to any entity within the Group that is outside the PRC.

The Group does not have any present plan to pay any cash dividends on its ordinary shares in the foreseeable future. It intends to retain most of its available funds and any future earnings for use in the operation and expansion of its business. As of December 31, 2017, the Group has not declared any dividends.

Deferred income taxes reflect the net tax effects of temporary differences between the carrying amount of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. The Group adopted ASU 2015-17 in the first quarter of 2017 and classified all deferred taxes assets and liabilities as noncurrent as of December 31, 2017. The Group did not retrospectively apply the changes to prior years. Significant components of the Group’s deferred tax assets and liabilities are as follows:


	As of December 31,
	2016			2017
Current deferred tax assets:
Impairment of loss on long term investments	$	72		$	—
Less: valuation allowance		—			—

Current deferred tax assets, net		72			—

Non-current deferred tax assets:
Advertising expense		—			5,957
Net operating tax losses carry-forward		2,852			3,964
Impairment on long term investments and game copyright		208			400
Accrued expenses		—			840
Less: valuation allowance		(2,852	)		(3,964	)

Non-current deferred tax assets, net	$	208		$	7,197

Non-current deferred tax liabilities:
Intangible assets acquired		—			1,866

Non-current deferred tax assets, net	$	—		$	1,866

The Group considers the following factors, among other matters, when determining whether some portion or all of the deferred tax assets will more likely than not be realized: the nature, frequency and severity of losses, forecasts of future profitability, the duration of statutory carry-forward periods, the Group’s experience with tax attributes expiring unused and tax planning alternatives. The Group’s ability to realize deferred tax assets depends on its ability to generate sufficient taxable income within the carry-forward periods provided for in the tax law.

As of December 31, 2017, the tax loss carry-forward for Beijing Momo’s subsidiaries amounted to $5,431, which would expire on various dates between December 31, 2020 and December 31, 2022. As of December 31, 2017, the tax loss carryforward for Momo HK amounted to $178, which would be carried forward indefinitely and set off against its future taxable profits. As of December 31, 2017, the tax loss carry-forward for Momo US amounted to $8,985, which would be carried forward for twenty years. The Group does not file combined or consolidated tax returns, therefore, losses from individual subsidiaries or the VIE may not be used to offset other subsidiaries’ or VIE’s earnings within the Group. Valuation allowance is considered on each individual subsidiary and legal entity basis. Valuation allowances have been established in respect of certain deferred tax assets as it is considered more likely than not that the relevant deferred tax assets will not be realized in the foreseeable future.

Reconciliation between income tax expense computed by applying the PRC EIT rate of 25% to income before income taxes and the actual provision for income tax is as follows:


	For the years ended December 31,
	2015			2016			2017
Net income before provision for income tax	$	13,419		$	146,915		$	378,115
PRC statutory tax rate		25	%		25	%		25	%
Income tax expense at statutory tax rate		3,355			36,729			94,529
Permanent differences		(144	)		(75	)		(66	)
Change in valuation allowance		(2,315	)		(2,680	)		1,112
Effect of income tax rate difference in other jurisdictions		2,754			7,941			11,857
Effect of tax holidays and preferential tax rates		(3,558	)		(36,779	)		(41,452	)

Provision for income tax	$	92		$	5,136		$	65,980

If Beijing Momo IT and Chengdu Momo did not enjoy income tax exemptions and preferential tax rates for the years ended December 31, 2015, 2016 and 2017, the increase in income tax expenses and net income per share amounts would be as follows:


	For the years ended December 31,
	2015		2016		2017
Increase in income tax expenses	$	3,558	$	36,779	$	41,452
Net income per ordinary share attributable to Momo Inc. – basic		0.03		0.28		0.70
Net income per ordinary share attributable to Momo Inc. - diluted		0.03		0.27		0.67

No significant unrecognized tax benefit was identified for the years ended December 31, 2015, 2016 and 2017. The Group did not incur any interest and penalties related to potential underpaid income tax expenses and also believed that uncertainty in income taxes did not have a significant impact on the unrecognized tax benefits within next twelve months.

Ordinary Shares

12 Months Ended

Dec. 31, 2017

Equity [Abstract]

Ordinary Shares

11.

ORDINARY SHARES

On November 23, 2011, the Company was authorized to issue a maximum 500,000,000 shares of a single class and issued 147,000,000 ordinary shares with a par value of $0.0001.

On April 12, 2012, the authorized 500,000,000 shares were divided into 446,545,450 ordinary shares and 53,454,550 preferred shares in connection with the issuance of Series A-1 and A-2 convertible redeemable participating preferred shares.

In April 2012, the Company’s four founding shareholders entered into an arrangement with the investor in conjunction with the issuance of Series A convertible redeemable participating preferred shares, whereby all of their 147,000,000 ordinary shares (“Founders’ shares”) became subject to service and transfer restrictions. Such Founders’ shares are subject to repurchase by the Company upon early termination of four years of employment of four founders from April 2012. Notwithstanding the foregoing, the Founders shall exercise all rights and privileges of a holder of ordinary shares of the Company with respect to the Founders’ shares. The Founders shall be deemed to be the holder for purposes of receiving any dividends that may be paid with respect to the Founders’ shares and for the purpose of exercising any voting rights relating to the Founders’ shares, even if some or all of Founders’ shares have not yet vested and been released from the repurchase rights. The restrictions on the ordinary shares were fully released and such shares became fully vested in 2016. Please refer to Note 12 for disclosure of nonvested restricted shares.

On June 11, 2012, the Company decreased its authorized ordinary shares from 446,545,450 shares to 426,747,470 shares in connection with the issuance of Series A-3 convertible redeemable participating preferred shares.

On July 13, 2012, the Company decreased its authorized ordinary shares from 426,747,470 shares to 366,789,830 shares in connection with the issuance of Series B convertible redeemable participating preferred shares.

On September 12, 2012, a 10-for-1 stock split for all ordinary shares, Series A-1, A-2 and A-3 and Series B convertible redeemable participating preferred shares was approved by the shareholders. While the stock split increased the number of shares for each stockholder, the percentage of their ownership in the Company was not affected. This share split has been retrospectively reflected for all periods presented. In addition, the Company increased its authorized ordinary shares from 366,789,830 to 371,684,330 in connection with the preferred share transfer between investors.

On October 8, 2013, the Company was authorized to issue a maximum 1,000,000,000 shares, which was divided into 835,675,688 ordinary shares and 164,324,312 preferred shares in connection with the issuance of Series C convertible redeemable participating preferred shares.

On April 22, 2014, the Company was authorized to issue a maximum 1,000,000,000 shares, which was divided into 799,281,189 ordinary shares and 200,718,811 preferred shares in connection with the issuance of Series D convertible redeemable participating preferred shares.

On April 22, 2014, certain ordinary shareholders who are also the senior management of the Company donated an aggregate of 15,651,589 ordinary shares to the Company with no consideration. On the same date, the Group declared a special dividend to these shareholders at an aggregated amount of $64,494, among which $58,044 was paid in May 2014. The remaining $5,775 and $675 were recorded as amount due to related parties-current and accrued expenses and other current liabilities respectively, as of December 31, 2017. Please refer to Note 15 for disclosure of related party balances and transactions. The Company treated the whole transaction as a repurchase of ordinary shares of which the repurchase price is considerably lower than the fair value of ordinary share. All such shares were recorded as treasury stock.

On November 28, 2014, the Company was authorized to issue a maximum 1,000,000,000 ordinary shares, which was divided into 800,000,000 Class A Ordinary Shares, 100,000,000 Class B Ordinary Shares and 100,000,000 shares of such class designated as the Board may determine.

On December 16, 2014, the Company completed its IPO and a concurrent private placement upon which the Company’s ordinary shares were divided into Class A ordinary shares and Class B ordinary shares. The Company newly issued 45,688,888 Class A ordinary shares, consisting of (i) 36,800,000 Class A ordinary shares offered through IPO, and (ii) 8,888,888 Class A ordinary shares issued in connection with the concurrent private placement. All of the Company’s Series A, Series B, Series C and Series D preferred shares were automatically converted into 200,718,811 Class A ordinary shares.

In 2015, 2016 and 2017, 5,995,293, 5,197,032 and 9,476,874 ordinary shares were issued in connection with the exercise of options and vesting of restricted share units previously granted to employees, executives and consultants under the Company’s share incentive plans (see Note 12), respectively.

As of December 31, 2017, there were 314,060,843 Class A ordinary shares and 84,364,466 Class B ordinary shares issued and outstanding, par value $0.0001 per share.

Share-Based Compensation

12 Months Ended

Dec. 31, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Share-Based Compensation

12.

SHARE-BASED COMPENSATION

Share options granted by the Company

In November 2012, the Company adopted a share incentive plan (“2012 Plan”), which was amended in October 2013. The maximum aggregate number of shares which may be issued pursuant to all awards under the 2012 Plan is 44,758,220 ordinary shares.

In November, 2014, the Company adopted the 2014 share incentive plan (“2014 Plan”), pursuant to which a maximum aggregate of 14,031,194 Class A ordinary shares may be issued pursuant to all awards granted thereunder. Starting from 2017, the number of shares reserved for future issuances under the 2014 Plan will be increased by a number equal to 1.5% of the total number of outstanding shares on the last day of the immediately preceding calendar year, or such lesser number of Class A ordinary shares as determined by the Company’s board of directors, on the first day of each calendar year during the term of the 2014 Plan. With the adoption of the 2014 Plan, the Company will no longer grant any incentive shares under the 2012 Plan. The time and condition to exercise options will be determined by the Board or a committee of the Board. The term of the options may not exceed ten years from the date of the grant, except for the situation of amendment, modification and termination. Under the 2014 Plan, share options are subject to vesting schedules ranging from two to four years.

The following table summarizes the option activity for the year ended December 31, 2017:


	Number of options			Weighted average exercise price per option		Weighted average remaining contractual life (years)		Aggregated intrinsic value
Outstanding as of January 1, 2017		31,606,466		$	0.0641		7.63	$	288,439

Granted		5,771,226		$	0.0002
Exercised		(9,426,874	)	$	0.0602
Forfeited		(981,527	)	$	0.0132

Outstanding as of December 31, 2017		26,969,291		$	0.0536		7.40		328,658

Exercisable as of December 31, 2017		14,743,283		$	0.0952		6.39	$	170,053

There were 14,743,283 vested options, and 11,114,843 options expected to vest as of December 31, 2017. For options expected to vest, the weighted-average exercise price was $0.0036 as of December 31, 2017 and aggregate intrinsic value was $137,765 and $136,006 as of December 2016 and 2017, respectively.

The weighted-average grant-date fair value of the share options granted during the years 2015, 2016, and 2017 was $5.93, $6.24 and $17.41, respectively. Total intrinsic value of options exercised for the years ended December 31, 2015, 2016 and 2017 was $45,885, $45,581and $154,233 respectively. The total fair value of options vested during the years ended December 31, 2015, 2016 and 2017 was $13,680, $27,171 and $37,979, respectively.

In May 2015, the Company accelerated the vesting to permit immediate exercise of 235,000 outstanding employee share options granted under the 2012 Plan. The incremental cost resulting from the modification amounted to $162 and was recorded as share based compensation during the year ended December 31, 2015.

In July 2016, the Company canceled 187,500 outstanding employee share options granted under the 2014 Plan for one employee. As a result, the Company immediately recognized the unvested compensation cost attributable to the canceled award amounting to $1,532 in 2016.

The fair value of options granted was estimated on the date of grant using the Black-Sholes pricing model after the Company completed its IPO, with the following assumptions used for grants during the applicable periods:


	Risk-free interest rate of return			Contractual term		Volatility			Dividend yield		Exercise price
2015		2.15%~2.19	%		10 years		55.3%~55.7	%		—	$	0.0002
2016		1.75%~2.70	%		10 years		52.5%~55.3	%		—	$	0.0002
2017		2.47%~2.87	%		10 years		50.7%~54.0	%		—	$	0.0002

(1)

Risk-free interest rate

Risk-free interest rate was estimated based on the yield to maturity of China international government bonds with a maturity period close to the expected term of the options.

(2)

Contractual term

The Company used the original contractual term.

(3)

Volatility

The volatility of the underlying ordinary shares during the life of the options was estimated based on the historical stock price volatility of comparable listed companies over a period comparable to the expected term of the options.

(4)

Dividend yield

The dividend yield was estimated by the Group based on its expected dividend policy over the expected term of the options.

(5)

Exercise price

The exercise price of the options was determined by the Group’s board of directors.

The fair value of the ordinary shares is determined as the closing sales price of the Shares as quoted on the principal exchange or system. For employee and executives share options, the Group recorded share-based compensation of $16,026, $28,096 and $42,439 during the years ended December 31, 2015, 2016 and 2017, respectively, based on the fair value on the grant dates over the requisite service period of award according to the vesting schedule for employee share option.

For non-employee share options the Group recorded share-based compensation of $756, $3,103 and $6,540 during the years ended December 31, 2015, 2016 and 2017, respectively, based on the fair value at the commitment date and recognized over the period the service is provided.

As of December 31, 2017, total unrecognized compensation expense relating to unvested share options was $122,171, which will be recognized over 2.95 years. The weighted-average remaining contractual term of options outstanding is 7.40 years.

Share options granted by Momo BVI

On January 3, 2015, Momo BVI, a wholly-owned subsidiary of the Group, approved Momo BVI Share Incentive Plan that provides for the issuance of not exceeding 30,000,000 share options. The option plan has a term of ten years unless earlier terminated by Momo BVI’s board of directors.

During the year ended December 31, 2015, Momo BVI granted 10,550,000 share options to its employees and executives with exercise prices ranging from $0.10 to $0.11 per share and vesting period of 4 years.

The following table summarizes the option activity for the year ended December 31, 2017:


	Number of options			Weighted average exercise price per option		Weighted average remaining contractual life (years)		Aggregated intrinsic value
Outstanding as of January 1, 2017		8,000,000		$	0.1088		8.19	$	10

Granted		—			—
Exercised		—			—
Forfeited		(5,000,000	)	$	0.1100

Outstanding as of December 31, 2017		3,000,000		$	0.1067		7.50	$	10

Exercisable as of December 31, 2017		1,812,500		$	0.1060		7.45	$	7

There were 1,812,500 vested options, and 1,033,125 options expected to vest as of December 31, 2017. For options expected to vest, the weighted-average exercise price is $0.1077 as of December 31, 2017 and aggregate intrinsic value was $18, $5 and $2 as of December 31, 2015, 2016 and 2017, respectively.

The weighted-average grant-date fair value of the share options granted during the years 2015, 2016, and 2017 was $0.0544, $ nil, and $nil, respectively. Total intrinsic value of options exercised was $nil for each of the years ended December 31, 2015, 2016 and 2017. The total fair value of options vested during the years ended December 31, 2015, 2016 and 2017 was $nil, $185 and $43, respectively.

For employee and executives share options, Momo BVI recorded share-based compensation of $98, $112 and $59 during the years ended December 31, 2015, 2016 and 2017, based on the fair value on the grant dates over the requisite service period of award according to the vesting schedule for employee share option.

As of December 31, 2017, total unrecognized compensation expense relating to unvested share options was $65, which will be recognized over 1.59 years. The weighted-average remaining contractual term of options outstanding is 7.50 years.

Non-vested restricted shares

In April 2012, the Company’s four founding shareholders entered into an arrangement with the investor in conjunction with the issuance of Series A preferred shares, whereby all of their 147,000,000 ordinary shares (“Founders’ shares”) became subject to service and transfer restrictions. Such Founders’ shares are subject to repurchase by the Company upon early termination of their four years of employment. The repurchase price is the par value of the ordinary shares. 25% of the Founders’ shares shall be vested annually. The restricted share agreements were subsequently amended on June 11, 2012 and July 18, 2012, respectively. Pursuant to the agreements, 25% of the Founders’ shares shall vest upon the closing of issuance of Series B preferred shares and the remaining 75% shall be vested monthly in equal installments over the next 36 months. This arrangement has been accounted for as a grant of restricted stock awards subject to service vesting conditions. Because the modification does not affect any of the other terms or conditions of the award, presumably the fair value before and after the modification is the same. The restrictions on the ordinary shares were fully released and such shares became fully vested in 2016.

On May 15, 2014, the Company’s four founding shareholders entered into an agreement with the investors to renew the arrangement. The Company considered the amendment of agreement as a modification of vesting of the restricted shares. Pursuant to the agreement, the Company shall be entitled to repurchase 50% and 25% of such shares in the case that founders terminate their employments with the Company before April 17, 2015 and during the period from April 17, 2015 to April 17, 2016, respectively, at a price of US$0.0001 per share or the lowest price permitted under applicable laws. Therefore, the Company considered that 50% of the total restricted shares were vested immediately on the amendment date and 25% shall be vested annually on April 17 in the next two years ending April 17, 2016. Before the modification date, May 15, 2014, there were 131,348,411 ordinary shares, of which 45,937,500 were unvested restricted shares. As the result of modification, 19,736,705 vested ordinary shares were classified to unvested restricted shares on the modification date and the corresponding compensation costs for these unvested restricted shares were amortized over the remaining service period. Because the modification does not affect any of the other terms or conditions of the award, the fair value of the restricted shares before and after the modification is the same.

A summary of non-vested restricted share activity during the years ended December 31, 2015, 2016 and 2017 is presented below:


	Number of shares
Outstanding as of January 1, 2015		57,250,756
Granted		—
Modification		—
Vested		(28,625,378	)

Outstanding as of December 31, 2015		28,625,378
Granted		—
Forfeited		—
Vested		(28,625,378	)

Outstanding as of December 31, 2016		—

The weighted average grant date fair value of the non-vested restricted shares was $0.01 per share and the aggregated fair value was $1,470. The total fair value of non-vested restricted shares vested during the years ended December 31, 2015, 2016 and 2017 was $286, $286 and $nil, respectively.

The Company recorded compensation expense of $180, $52 and $nil during the years ended December 31, 2015, 2016 and 2017, respectively, related to non-vested restricted shares.

As of December 31, 2017, total unrecognized compensation expense relating to the non-vested restricted shares was $nil.

Restricted share units (“RSUs”)

On December 11, 2014, the Company granted a total of 40,001 shares of RSUs to independent directors under the 2014 Plan. The restricted share units will vest in accordance with the vesting schedule set out in the RSUs award agreement, which is 50% of the RSUs shall vest at the end of every six months since the grant date.

On May 17, 2016, the Company granted a total of 200,000 shares of RSUs to independent directors under the 2014 Plan and vesting period of 4 years, which began from December 11, 2015. On March 7, 2017, the Company granted a total of 100,000 shares of RSUs to independent directors under the 2014 Plan and vesting period of 4 years, which began from March 7, 2017.

The Company will forfeit the unvested portion of the RSUs if the grantees terminate their service during the vesting period.

The fair value of these RSUs is measured on the grant date based on the market price of the ordinary share on the grant date. The following table summarizes information regarding the share units granted:


	Number of shares
Outstanding as of January 1, 2017		150,000
Granted		100,000
Forfeited		—
Vested		(50,000	)

Outstanding as of December 31, 2017		200,000

The weighted-average grant-date fair value of the restricted share units granted during the years 2015, 2016, and 2017 was $ nil, $6.50 and $15.00, respectively. Total intrinsic value of the restricted share units exercised for the years ended December 31, 2015, 2016 and 2017 was $301, $511 and $821, respectively. The total fair value of the restricted share units vested during the years ended December 31, 2015, 2016 and 2017 was $340, $325 and $325, respectively. The aggregated fair value of RSUs was $340, $1,299 and $1,500 respectively, for the grant date of December 11, 2014, May 17, 2016 and March 7, 2017.

The Group recorded share-based compensation of $322, $343 and $619 for RSUs for the years ended December 31, 2015, 2016 and 2017, respectively, based on the fair value on the grant dates over the requisite service period of award using the straight-line method.

As of December 31, 2017, total unrecognized compensation expense relating to unvested RSUs was $1,838, which will be recognized over 2.76 years. The weighted-average remaining contractual term of RSUs outstanding is 8.56 years.

Net Income Per Share

12 Months Ended

Dec. 31, 2017

Earnings Per Share [Abstract]

Net Income Per Share

13.

NET INCOME PER SHARE

For the years ended December 31, 2015 and 2016, the Group determined that the nonvested restricted shares are participating securities as the holders of the nonvested restricted shares have a nonforfeitable right to receive dividends with all ordinary shares but the nonvested restricted shares do not have a contractual obligation to fund or otherwise absorb the Group’s losses. Accordingly, the Group uses the two-class method of computing net income per share, for ordinary shares and nonvested restricted shares according to the participation rights in undistributed earnings.

The calculation of net income per share is as follows:


	For the years ended December 31,
	2015			2016			2017
Numerator:
Net income attributable to MomoInc.	$	13,697		$	145,250		$	318,566
Undistributed earnings allocated to participating nonvested restricted shares		(1,339	)		(3,197	)		—

Net income attributed to ordinary shareholders for computing net income per ordinary share-basic and diluted	$	12,358		$	142,053		$	318,566


	For the years ended December 31,
	2015		2016		2017
Denominator:
Denominator for computing net income per share-basic:
Weighted average ordinary shares outstanding used in computing net income per ordinary share-basic		342,646,282		377,335,923		394,549,323
Weighted average shares used in computing net income per participating nonvested restricted share		37,118,622		8,493,244		—

Denominator for computing net income per share-diluted:
Weighted average shares outstanding used in computing net income per ordinary share-diluted		401,396,548		407,041,165		415,265,078

Net income per ordinary share attributable to Momo Inc. - basic	$	0.04	$	0.38	$	0.81
Net income per participating nonvested restricted share	$	0.04	$	0.38	$	—

Net income per ordinary share attributable to Momo Inc. - diluted	$	0.03	$	0.36	$	0.77

The following table summarizes potential ordinary shares outstanding excluded from the computation of diluted net income per ordinary share for the years ended December 31, 2015, 2016 and 2017, because their effect is anti-dilutive:


	For the years ended December 31,
	2015		2016		2017
Share issuable upon exercise of share options		904,489		152,500		768,266
Share issuable upon exercise of RSUs		15,001		50,000		—

Commitments and Contingencies

12 Months Ended

Dec. 31, 2017

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

14.

COMMITMENTS AND CONTINGENCIES

Lease commitment

The Group leases certain office premises under non-cancellable leases. These leases expire through 2022 and are renewable upon negotiation. Rental expenses under operating leases for the years ended December 31, 2015, 2016 and 2017 were $3,715, $4,743 and $8,744, respectively.

Future minimum payments under non-cancellable operating leases as of December 31, 2017 were as follows:


2018	$	7,671
2019		4,230
2020		2,990
2021		2,262

Total	$	17,153

Investment commitments

The Group was obligated to subscribe $2,942 and $ 4,611 for partnership interest and equity interest of certain long-term investees under various arrangements as of December 31, 2016 and 2017, respectively.

Contingencies

The Group is subject to legal proceedings in the ordinary course of business. The Group does not believe that any currently pending legal or administrative proceeding to which the Group is a party will have a material effect on its business or financial condition.

Related Party Balances and Transactions

12 Months Ended

Dec. 31, 2017

Related Party Balances and Transactions

15.

RELATED PARTY BALANCES AND TRANSACTIONS


Major related parties		Relationship with the Group
Hangzhou Alimama Technology Co., Ltd. (i)		Affiliates of a Major Shareholder
Guangzhou UC Network Technology Co., Ltd. (i)		Affiliates of a Major Shareholder
Guangzhou Aijiuyou Informational Technology Co., Ltd. (i)		Affiliates of a Major Shareholder
Alibaba Cloud Computing Ltd. (i)		Affiliates of a Major Shareholder
Taobao (China) Software Co., Ltd. (i)		Affiliates of a Major Shareholder
Zhejiang Tmall Technology Co., Ltd. (i)		Affiliates of a Major Shareholder
Shanghai Touch Future Network Technology Co., Ltd.		Long-term investee
Shanghai Xisue Network Technology Co., Ltd.		Affiliate of long-term investee
Hunan Qindao Cultural Spread Ltd.		Long-term investee
Hunan Qindao Network Media Technology Co., Ltd.		Affiliate of long-term investee
Hangzhou Yihong Advertisement Co., Ltd. (i)		Affiliates of a Major Shareholder
Guangzhou Jianyue Information Technology Co., Ltd. (i)		Affiliates of a Major Shareholder

(i)

The parent company of these entities ceased to be a major shareholder of the Group in November 2017.

(1)

Amount due from related parties-current


	As of December 31,
	2016		2017
Hunan Qindao Network Media Technology Co., Ltd. (ii)	$	—	$	5,143
Hangzhou Alimama Technology Co., Ltd.		2		—
Guangzhou UC Network Technology Co., Ltd.		5		—
Guangzhou Aijiuyou Informational Technology Co., Ltd.		81		—

Total	$	88	$	5,143

(ii)

The amount of $5,143 as of December 31, 2017 represented the advance payment of revenue sharing of live video service made to Hunan Qindao Network Media Technology Co., Ltd.

(2)

Amount due to related parties - current


	As of December 31,
	2016		2017
Amount due to ordinary shareholders (iii)	$	5,862	$	5,775
Hunan Qindao Cultural Spread Ltd.		1,281		—
Alibaba Cloud Computing Ltd.		629		—
Shanghai Touch Future Network Technology Co., Ltd.		229		—
Taobao (China) Software Co., Ltd.		116		—
Others		—		29

Total	$	8,117	$	5,804

(iii)

The amounts of $5,862 and $5,775 as of December 31, 2016 and 2017 primarily included the unpaid repurchase amount by the Group to its ordinary shareholders. Please refer to Note 11 for repurchase of ordinary shares.

(3)

Sales to related parties


	For the years ended December 31,
	2015		2016		2017
Hangzhou Yihong Advertisement Co., Ltd. (iv)	$	—	$	—	$	2,614
Hangzhou Alimama Technology Co., Ltd. (iv)		6,002		42		342
Guangzhou Aijiuyou Informational Technology Co., Ltd. (v)		—		400		184
Zhejiang Tmall Technology Co., Ltd. (iv)		—		820		74
Shanghai Xisue Network Technology Co., Ltd.		—		922		—
Taobao (China) Software Co., Ltd. (iv)		—		249		—
Others		—		9		2

Total	$	6,002	$	2,442	$	3,216

(iv)

The sales to related parties represented mobile marketing services provided.

(v)

The sales to related parties represented mobile game revenue generated through those game operating companies.

(4)

Purchase from related parties


	For the years ended December 31,
	2015		2016		2017
Hunan Qindao Network Media Technology Co., Ltd. (vi)	$	—	$	—	$	20,639
Alibaba Cloud Computing Ltd. (vii)		322		3,360		11,060
Hunan Qindao Cultural Spread Ltd. (vi)		—		3,929		9,131
Taobao (China) Software Co., Ltd.		—		323		338
Guangzhou Jianyue Information Technology Co., Ltd.		—		—		119
Shanghai Touch future Network Technology Co., Ltd.		—		347		—

Total	$	322	$	7,959	$	41,287

(vi)

The purchases from Hunan Qindao Network Media Technology Co., Ltd. and Hunan Qindao Cultural Spread Ltd. represent the revenue sharing with broadcaster agencies of live video service.

(vii)

The purchase from Alibaba Cloud Computing Ltd. is mainly related to its cloud computing services.

Segment Information

12 Months Ended

Dec. 31, 2017

Segment Reporting [Abstract]

Segment Information

16.

SEGMENT INFORMATION

The Group’s chief operating decision maker has been identified as the Chief Executive Officer (“CEO”), who reviews consolidated results when making decisions about allocating resources and assessing performance of the Group. The Group’s revenue and net income are substantially derived from live video service, value-added services, mobile marketing services, mobile games and other services. The Group does not have discrete financial information of costs and expenses between various services in its internal reporting, and reports costs and expenses by nature as a whole. Therefore, the Group has one operating segment.

The table below is only presented at the revenue level with no allocations of direct or indirect cost and expenses. The Group operates in the PRC; most of the Group’s long-lived assets are located in the PRC and all services are provided in the PRC.

Components of revenues are presented in the following table:


	For the years ended December 31,
	2015		2016		2017
Live video service	$	1,231	$	376,925	$	1,102,592
Value-added service		58,462		67,603		103,139
Mobile marketing		38,885		66,339		76,178
Mobile games		31,082		35,453		35,619
Other services		4,328		6,778		743

Total	$	133,988	$	553,098	$	1,318,271

Statutory Reserves and Restricted Net Assets

12 Months Ended

Dec. 31, 2017

Receivables [Abstract]

Statutory Reserves and Restricted Net Assets

18.

STATUTORY RESERVES AND RESTRICTED NET ASSETS

In accordance with the Regulations on Enterprises with Foreign Investment of China and their articles of association, the Group’s subsidiaries and VIE located in the PRC, being foreign invested enterprises established in the PRC, are required to provide for certain statutory reserves. These statutory reserve funds include one or more of the following: (i) a general reserve, (ii) an enterprise expansion fund or discretionary reserve fund, and (iii) a staff bonus and welfare fund. Subject to certain cumulative limits, the general reserve fund requires a minimum annual appropriation of 10% of after-tax profit (as determined under accounting principles generally accepted in China at each year-end); the other fund appropriations are at the subsidiaries’ or the affiliated PRC entities’ discretion. These statutory reserve funds can only be used for specific purposes of enterprise expansion, staff bonus and welfare, and are not distributable as cash dividends except in the event of liquidation of our subsidiaries, our affiliated PRC entities and their respective subsidiaries. The Group’s subsidiaries and VIE are required to allocate at least 10% of their after tax profits to the general reserve until such reserve has reached 50% of their respective registered capital.

Appropriations to the enterprise expansion reserve and the staff welfare and bonus reserve are to be made at the discretion of the board of directors of each of the Group’s subsidiaries.

The appropriations to these reserves by the Group’s PRC subsidiary, VIE and VIE’s subsidiaries were $553, $17,969 and $27,430 for the years ended December 31, 2015, 2016 and 2017.

Relevant PRC laws and regulations restrict the WFOE, VIE and VIE’s subsidiaries from transferring a portion of their net assets, equivalent to the balance of their statutory reserves and their paid in capital, to the Company in the form of loans, advances or cash dividends. The WFOE’s accumulated profits may be distributed as dividends to the Company without the consent of a third party. The VIE and VIE’s subsidiaries’ revenues and accumulated profits may be transferred to the Company through contractual arrangements without the consent of a third party. Under applicable PRC law, loans from PRC companies to their offshore affiliated entities require governmental approval, and advances by PRC companies to their offshore affiliated entities must be supported by bona fide business transactions. The capital and statutory reserves restricted which represented the amount of net assets of the Group’s PRC subsidiary, VIE and VIE’s subsidiaries in the Group not available for distribution were $91,008, $108,977 and $136,407 as of December 31, 2015, 2016 and 2017, respectively.

Subsequent Events

12 Months Ended

Dec. 31, 2017

Subsequent Events [Abstract]

Subsequent Events

19.

SUBSEQUENT EVENTS

New acquisition

On February 23, 2018, the Group reached a definitive agreement with Tantan Limited (“Tantan”) and all of its shareholders, pursuant to which the Group agreed to acquire 100% fully diluted equity stake in Tantan for a combination of share consideration and cash, including approximately 5,300,000 newly issued Class A ordinary shares of the Company and $600.9 million in cash, of which $229.8 million has been paid. Tantan primarily operates a social and dating app in China for the young generation. The deal is expected to close in the second quarter of 2018, subject to customary closing conditions. The Group is in the process of evaluating the accounting treatment on this acquisition.

Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2017

Basis of presentation

The consolidated financial statements of the Group have been prepared in accordance with the accounting principles generally accepted in the United States of America (“U.S. GAAP”).

Basis of consolidation

Use of estimates

Cash and cash equivalents

Term deposits

Term deposits consist of bank deposits with an original maturity of over three months.

Accounts receivable

Financial instruments

Foreign currency risk

Cost method investments

Equity method investments

An impairment change is recorded if the carrying amount of the investment exceeds its fair value and this condition is determined to be other-than-temporary.

Available-for-sale Investments

Property and equipment, net

Property and equipment are stated at cost less accumulated depreciation. Depreciation is calculated on a straight-line basis over the following estimated useful lives:


Office equipment			3-5 years
Computer equipment			3 years
Vehicles			5 years
Leasehold improvement			Shorter of the lease term or estimated useful lives

Intangible assets


Copyright			1 year
License			3.2-10 years

Impairment of long-lived assets with finite lives

Goodwill

Fair value

Level 1

Level 1 applies to assets or liabilities for which there are quoted prices in active markets for identical assets or liabilities.

Level 2

Level 3

Level 3 applies to assets or liabilities for which there are unobservable inputs to the valuation methodology that are significant to the measurement of the fair value of the assets or liabilities.

Revenue recognition

(a)

Live video service

Net revenues of $1,231, $376,925 and $1,102,592 were recognized for live video services for the years ended December 31, 2015, 2016 and 2017, respectively.

(b)

Value-added services

Net revenues of $58,462, $67,603 and $103,139 were recognized for value-added services for the years ended December 31, 2015, 2016 and 2017, respectively.

(c)

Mobile marketing

The Group provides advertising and marketing solutions to customers for promotion of their brands and conduction of effective marketing activities through its mobile application.

Display-based mobile marketing services

Performance-based mobile marketing services

The Group’s revenue transactions are based on standard business terms and conditions, which are recognized net of agency rebates, if applicable.

Net revenues of $38,885, $66,339 and $76,178 were recognized for mobile marketing for the years ended December 31, 2015, 2016 and 2017, respectively.

(d)

Mobile games

The Group publishes both licensed mobile games developed by third-party game developers and its self-developed games to the game players through its mobile application.

Licensed mobile games

Licensed mobile games - Non-exclusive mobile games services

Licensed mobile games - Exclusive mobile games services

Self-developed mobile game

Net revenues of $31,082, $35,453 and $35,619 were recognized for mobile games for the years ended December 31, 2015, 2016 and 2017, respectively.

(e)

Other service

Other service primarily includes Duobao service and paid emoticons.

Advertising barter transactions

Deferred revenue

Cost of revenues

Government subsidies

Research and development expenses

Value added taxes ("VAT")

Value added taxes (“VAT”)

Income taxes

Foreign currency translation

Operating leases

Advertising expenses

Comprehensive income

Share-based compensation

Share awards issued to consultants are measured at fair value at the earlier of the commitment date or the date the services are completed and recognized over the period the services are provided.

Earnings per share

Basic earnings per ordinary share is computed by dividing net income attributable to ordinary shareholders by the weighted average number of ordinary shares outstanding during the period.

Recent accounting pronouncement adopted

Recent accounting pronouncements not yet adopted

•

Step 1: Identify the contract (s) with a customer.

•

Step 2: Identify the performance obligations in the contract.

•

Step 3: Determine the transaction price.

•

Step 4: Allocate the transaction price to the performance obligations in the contract.

•

Step 5: Recognize revenue when (or as) the entity satisfies a performance obligation.

In January, 2016, the FASB issued a new pronouncement ASU 2016-01 which is intended to improve the recognition and measurement of financial instruments. The ASU affects public and private companies, not-for-profit organizations, and employee benefit plans that hold financial assets or owe financial liabilities.

The new guidance makes targeted improvements to existing U.S. GAAP by:

•

Requiring public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes;

•

Eliminating the requirement to disclose the fair value of financial instruments measured at amortized cost for organizations that are not public business entities;

•

Accounts Receivable [Member]

Concentration of credit risk and revenue

Concentration of credit risk

Third-party application stores and other payment channels accounting for 10% or more of accounts receivables are as follows:


	As of December 31,
	2016			2017
A		40	%		23	%
B		—			21	%
C		15	%		19	%
D		22	%		5	%

No user or advertising customer accounted for 10% or more of accounts receivables for the years ended December 31, 2016 and 2017, respectively.

Revenues [Member]

Concentration of credit risk and revenue

Concentration of revenue

No user or customer accounted for 10% or more of net revenues for the years ended December 31, 2015, 2016 and 2017, respectively.

Organization and Principal Activities (Tables)

12 Months Ended

Dec. 31, 2017

Text Block [Abstract]

Schedule of Subsidiaries, VIE and VIE's Subsidiaries

As of December 31, 2017, details of the Company’s subsidiaries, VIE and VIE’s subsidiaries are as follows:

Date of
incorporation or
acquisition

Place of
incorporation

Percentage
of economic
ownership

Subsidiaries

Momo Technology HK Company Limited (“Momo HK”)

December 5, 2011

Hong Kong

100

Beijing Momo Information Technology Co., Ltd. (“Beijing Momo IT”)

March 9, 2012

PRC

100

Momo Technology Overseas Holding Company Limited (“Momo BVI”)

March 5, 2014

BVI

100

Momo Information Technologies Corp. (“Momo US”)

March 7, 2014

100

VIE

Beijing Momo Technology Co., Ltd. (“Beijing Momo”)

July 7, 2011

PRC

N/A

VIE’s subsidiaries

Chengdu Momo Technology Co., Ltd. (“Chengdu Momo”)

May 9, 2013

PRC

N/A

Shanghai Momo Technology Co., Ltd. (“Shanghai Momo”)

January 19, 2015

PRC

N/A

Chengdu Biyou Technology Co., Ltd. (“Chengdu Biyou”)

October 16, 2015

PRC

N/A

Tianjin Heer Technology Co., Ltd (“Tianjin Heer”)

March 7, 2016

PRC

N/A

Momo Pictures Co., Ltd.

November 11, 2016

PRC

N/A

QOOL Media (Tianjin) Co., Ltd

November 16, 2016

PRC

N/A

Zhejiang Shengdian Digital Network Co., Ltd. (“Zhejiang Shengdian”)

March 31, 2017

PRC

N/A

Beijing Santi Cloud Union Technology Co., Ltd. (“Santi”)

June 30,2017

PRC

N/A

Loudi Momo Technology Co., Ltd. (“Loudi Momo”)

July 17, 2017

PRC

N/A

Changsha Heer Network Co., Ltd. (“Changsha Heer”)

September 20,2017

PRC

N/A

Beijing Santi Cloud Time Technology Co., Ltd.

September 26,2017

PRC

N/A

*	These entities are controlled by the Company pursuant to the contractual arrangements disclosed below.

Schedule of Amounts and Balances of VIE Included in Consolidated Financial Statements After Elimination of Intercompany Balances and Transactions


	As of December 31,
	2016		2017
Cash and cash equivalents	$	36,855	$	63,110
Accounts receivable, net of allowance for doubtful accounts of $nil and $90 as of December 31, 2016 and 2017, respectively		36,078		39,597
Amount due from related parties		88		5,143
Prepaid expenses and other current assets		20,613		57,056
Deferred tax assets, current		72		—
Short-term investment		—		1,614

Total current assets		93,706		166,520

Property and equipment, net		1,854		8,080
Intangible assets		—		7,462
Rental deposits		325		1,609
Other non-current assets		2,593		7,685
Long term investments		26,541		43,333
Deferred tax assets, non-current		208		1,062
Goodwill		—		3,401

Total assets		125,227		239,152

Accounts payable		36,812		54,937
Deferred revenue		41,277		64,788
Accrued expenses and other current liabilities		6,632		30,802
Amounts due to related parties		1,510		29
Income tax payable		3,881		11,765

Total current liabilities		90,112		162,321

Deferred tax liabilities, non-current		—		1,866

Total liabilities	$	90,112	$	164,187


	For the years ended December 31,
	2015			2016			2017
Net revenues	$	133,988		$	553,098		$	1,318,271
Net income	$	118,404		$	340,366		$	724,880
Net cash provided by operating activities	$	124,786		$	360,433		$	740,683
Net cash used in investing activities	$	(19,435	)	$	(11,027	)	$	(25,810	)
Net cash provided by financing activities	$	—		$	—		$	73

- Definition

Tabular disclosure of the significant judgments and assumptions made in determining whether a variable interest (as defined) held by the entity requires the variable interest entity (VIE) (as defined) to be consolidated and (or) disclose information about its involvement with the VIE, individually or in aggregate (as applicable); the nature of restrictions, if any, on the consolidated VIE's assets and on the settlement of its liabilities reported by an entity in its statement of financial position, including the carrying amounts of such assets and liabilities; the nature of, and changes in, the risks associated with involvement in the VIE; how involvement with the VIE affects the entity's financial position, financial performance, and cash flows; the lack of recourse if creditors (or beneficial interest holders) of the consolidated VIE have no recourse to the general credit of the primary beneficiary (if applicable); the terms of arrangements, giving consideration to both explicit arrangements and implicit variable interests, if any, that could require the entity to provide financial support to the VIE, including events or circumstances that could expose the entity to a loss; the methodology used by the entity for determining whether or not it is the primary beneficiary of the variable interest entity; the significant factors considered and judgments made in determining that the power to direct the activities of a VIE that most significantly impact the VIE's economic performance are shared (as defined); the carrying amounts and classification of assets and liabilities of the VIE included in the statement of financial position; the entity's maximum exposure to loss, if any, as a result of its involvement with the VIE, including how the maximum exposure is determined and significant sources of the entity's exposure to the VIE; a comparison of the carrying amounts of the assets and liabilities and the entity's maximum exposure to loss; information about any liquidity arrangements, guarantees, and (or) other commitments by third parties that may affect the fair value or risk of the entity's variable interest in the VIE; whether or not the entity has provided financial support or other support (explicitly or implicitly) to the VIE that it was not previously contractually required to provide or whether the entity intends to provide that support, including the type and amount of the support and the primary reasons for providing the support; and supplemental information the entity determines necessary to provide.

+ References + Details

Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2017

Estimated Useful Lives

Depreciation is calculated on a straight-line basis over the following estimated useful lives:


Office equipment			3-5 years
Computer equipment			3 years
Vehicles			5 years
Leasehold improvement			Shorter of the lease term or estimated useful lives

Identifiable Intangible Assets Amortized over their estimated useful lives using the straight line method

Separately identifiable intangible assets that have determinable lives continue to be amortized over their estimated useful lives using the straight-line method as follows:


Copyright			1 year
License			3.2-10 years

Accounts Receivable [Member]

Schedules of Concentration of Risk, by Risk Factor

Third-party application stores and other payment channels accounting for 10% or more of accounts receivables are as follows:


	As of December 31,
	2016			2017
A		40	%		23	%
B		—			21	%
C		15	%		19	%
D		22	%		5	%

Accounts Receivable, Net (Tables)

12 Months Ended

Dec. 31, 2017

Receivables [Abstract]

Schedule of Accounts Receivable, Net

Accounts receivable, net consisted of the following:


	As of December 31,
	2016		2017
Accounts receivable	$	36,078	$	39,687
Less: allowance for doubtful accounts		—		(90)

Accounts receivable, net	$	36,078	$	39,597

Prepaid Expenses and Other Current Assets (Tables)

12 Months Ended

Dec. 31, 2017

Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]

Schedule of Prepaid Expenses and Other Current Assets

Prepaid expenses and other current assets consisted of the following:


	As of December 31,
	2016		2017
Deposit at a third-party payment channel (i)	$	4,845	$	29,239
Advance to suppliers (ii)		5,331		21,521
Interest receivable		4,821		8,441
Prepaid income tax and other expenses		2,964		8,069
Deferred platform commission cost		4,571		4,292
Input VAT (iii)		2,968		3,714
Game promotions fees paid on behalf of game developers		2,250		2,742
Advance to game developers		1,550		924
Others		3,292		3,775

	$	32,592	$	82,717

(i)

(ii)

Advance to suppliers were primarily for advertising fees and live video broadcasting service fees.

(iii)

Long Term Investments (Tables)

12 Months Ended

Dec. 31, 2017

Investments Schedule [Abstract]

Summary of Equity and Cost Method Investments


	As of December 31,
	2016		2017
Equity method investments
Jingwei Chuangteng (Hangzhou) L.P. (i)	$	4,191	$	7,419
Beijing Autobot Venture Capital L.P. (ii)		6,736		8,478
Hangzhou Aqua Ventures Investment Management L.P. (iii)		9,187		12,986
Others (iv)		2,718		3,188

Cost method investments
Hunan Qindao Cultural Spread Ltd. (v)		—		4,611
Others (iv)		1,834		7,655

Available-for-sale investments
Xish International Limited (vi)		4,386		—
Hunan Qindao Cultural Spread Ltd. (v)		2,880		—

	$	31,932	$	44,337

(i)

(ii)

(iii)

(iv)

Others represent equity method investments or cost method investments that are individually insignificant.

(v)

(vi)

Property and Equipment, Net (Tables)

12 Months Ended

Dec. 31, 2017

Property, Plant and Equipment [Abstract]

Schedule of Property and Equipment, Net

Property and equipment, net consisted of the following:


	As of December 31,
	2016			2017
Computer equipment	$	23,763		$	45,580
Office equipment		4,370			12,214
Vehicles		31			189
Leasehold improvement		2,800			10,366
Less: accumulated depreciation		(18,844	)		(30,566	)
Exchange difference		1,812			1,979

		13,932		$	39,762

Intangible Assets, Net (Tables)

12 Months Ended

Dec. 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Intangible Assets

Intangible assets, net consisted of the following:


	As of December 31,
	2017
Licenses*	$	8,059
Game copyright		333
Less: accumulated amortization and impairment		(905	)
Exchange difference		(25	)

Net book value	$	7,462

Schedule of Future Amortization Expense

The estimated aggregate amortization expenses for each of the five succeeding fiscal years and thereafter are as follows:


For the year ended December 31,	Amounts
2018	$	881
2019		881
2020		881
2021		774
2022		771
Thereafter		3,274

	$	7,462

Accrued Expenses and Other Current Liabilities (Tables)

12 Months Ended

Dec. 31, 2017

Payables and Accruals [Abstract]

Schedule of Accrued Expenses and Other Current Liabilities

Accrued expenses and other current liabilities consisted of the following:


	As of December 31,
	2016		2017
Accrued payroll and welfare	$	18,982	$	34,523
Payable for advertisement		9,871		18,783
Balance of users’ virtual accounts		779		14,175
Other tax payables		4,694		9,457
Accrued professional services fee		1,438		3,417
VAT payable		1,919		1,543
Others		2,282		5,911

Total	$	39,965	$	87,809

Fair Value (Tables)

12 Months Ended

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Schedule of Assets Measured at Fair Value on Recurring Basis


	Fair Value Measurement as of December 31,
Description	2016		Quoted Prices in Active Market for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
			(Level 1)		(Level 2)		(Level 3)
Cash and cash equivalents	$	257,564	$	257,564		—	$	—
Available-for-sale investments		7,266		—		—		7,266

Total	$	264,830	$	257,564		—	$	7,266

	Fair Value Measurement as of December 31,
Description	2017		Quoted Prices in Active Market for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
			(Level 1)		(Level 2)		(Level 3)
Cash and cash equivalents	$	685,827	$	685,827		—	$	—

Total	$	685,827	$	685,827		—	$	—

Schedule of Reconciliation of Fair Value Measurement of Available-for-Sale Investments Using Significant Unobservable Inputs on a Recurring Basis

Additional information about the reconciliation of the fair value measurement of available-for-sale investments using significant unobservable inputs (level 3) on a recurring basis are is as follows:


Balance as of December 31, 2016	$	7,266
Purchase		1,458
Other-than-temporary loss recognized		(4,386	)
Reclassification to cost method investment (i)		(4,611	)
Foreign exchange difference		273

Balance as of December 31, 2017	$	—

(i)

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Components of Group's Deferred Tax Assets and Liabilities


	As of December 31,
	2016			2017
Current deferred tax assets:
Impairment of loss on long term investments	$	72		$	—
Less: valuation allowance		—			—

Current deferred tax assets, net		72			—

Non-current deferred tax assets:
Advertising expense		—			5,957
Net operating tax losses carry-forward		2,852			3,964
Impairment on long term investments and game copyright		208			400
Accrued expenses		—			840
Less: valuation allowance		(2,852	)		(3,964	)

Non-current deferred tax assets, net	$	208		$	7,197

Non-current deferred tax liabilities:
Intangible assets acquired		—			1,866

Non-current deferred tax assets, net	$	—		$	1,866

Schedule of Reconciliation between Income Tax Expense to Income before Income Taxes and Actual Provision for Income Tax

Reconciliation between income tax expense computed by applying the PRC EIT rate of 25% to income before income taxes and the actual provision for income tax is as follows:


	For the years ended December 31,
	2015			2016			2017
Net income before provision for income tax	$	13,419		$	146,915		$	378,115
PRC statutory tax rate		25	%		25	%		25	%
Income tax expense at statutory tax rate		3,355			36,729			94,529
Permanent differences		(144	)		(75	)		(66	)
Change in valuation allowance		(2,315	)		(2,680	)		1,112
Effect of income tax rate difference in other jurisdictions		2,754			7,941			11,857
Effect of tax holidays and preferential tax rates		(3,558	)		(36,779	)		(41,452	)

Provision for income tax	$	92		$	5,136		$	65,980

Increase in Income Tax Expenses and Net Income Per Share Amounts


	For the years ended December 31,
	2015		2016		2017
Increase in income tax expenses	$	3,558	$	36,779	$	41,452
Net income per ordinary share attributable to Momo Inc. – basic		0.03		0.28		0.70
Net income per ordinary share attributable to Momo Inc. - diluted		0.03		0.27		0.67

Share-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2017

Summary of Non-Vested Restricted Share Activity

A summary of non-vested restricted share activity during the years ended December 31, 2015, 2016 and 2017 is presented below:


	Number of shares
Outstanding as of January 1, 2015		57,250,756
Granted		—
Modification		—
Vested		(28,625,378	)

Outstanding as of December 31, 2015		28,625,378
Granted		—
Forfeited		—
Vested		(28,625,378	)

Outstanding as of December 31, 2016		—

Summary of Restricted Share Units Granted

The following table summarizes information regarding the share units granted:


	Number of shares
Outstanding as of January 1, 2017		150,000
Granted		100,000
Forfeited		—
Vested		(50,000	)

Outstanding as of December 31, 2017		200,000

Company Share Incentive Plan [Member]

Summary of Option Activity

The following table summarizes the option activity for the year ended December 31, 2017:


	Number of options			Weighted average exercise price per option		Weighted average remaining contractual life (years)		Aggregated intrinsic value
Outstanding as of January 1, 2017		31,606,466		$	0.0641		7.63	$	288,439

Granted		5,771,226		$	0.0002
Exercised		(9,426,874	)	$	0.0602
Forfeited		(981,527	)	$	0.0132

Outstanding as of December 31, 2017		26,969,291		$	0.0536		7.40		328,658

Exercisable as of December 31, 2017		14,743,283		$	0.0952		6.39	$	170,053

Schedule of Assumptions Used to Estimate Fair Value of Stock Options Granted


	Risk-free interest rate of return			Contractual term		Volatility			Dividend yield		Exercise price
2015		2.15%~2.19	%		10 years		55.3%~55.7	%		—	$	0.0002
2016		1.75%~2.70	%		10 years		52.5%~55.3	%		—	$	0.0002
2017		2.47%~2.87	%		10 years		50.7%~54.0	%		—	$	0.0002

Momo BVI Share Incentive Plan [Member]

Summary of Option Activity

The following table summarizes the option activity for the year ended December 31, 2017:


	Number of options			Weighted average exercise price per option		Weighted average remaining contractual life (years)		Aggregated intrinsic value
Outstanding as of January 1, 2017		8,000,000		$	0.1088		8.19	$	10

Granted		—			—
Exercised		—			—
Forfeited		(5,000,000	)	$	0.1100

Outstanding as of December 31, 2017		3,000,000		$	0.1067		7.50	$	10

Exercisable as of December 31, 2017		1,812,500		$	0.1060		7.45	$	7

Net Income Per Share (Tables)

12 Months Ended

Dec. 31, 2017

Earnings Per Share [Abstract]

Calculation of Net Income Per Share

The calculation of net income per share is as follows:


	For the years ended December 31,
	2015			2016			2017
Numerator:
Net income attributable to MomoInc.	$	13,697		$	145,250		$	318,566
Undistributed earnings allocated to participating nonvested restricted shares		(1,339	)		(3,197	)		—

Net income attributed to ordinary shareholders for computing net income per ordinary share-basic and diluted	$	12,358		$	142,053		$	318,566


	For the years ended December 31,
	2015		2016		2017
Denominator:
Denominator for computing net income per share-basic:
Weighted average ordinary shares outstanding used in computing net income per ordinary share-basic		342,646,282		377,335,923		394,549,323
Weighted average shares used in computing net income per participating nonvested restricted share		37,118,622		8,493,244		—

Denominator for computing net income per share-diluted:
Weighted average shares outstanding used in computing net income per ordinary share-diluted		401,396,548		407,041,165		415,265,078

Net income per ordinary share attributable to Momo Inc. - basic	$	0.04	$	0.38	$	0.81
Net income per participating nonvested restricted share	$	0.04	$	0.38	$	—

Net income per ordinary share attributable to Momo Inc. - diluted	$	0.03	$	0.36	$	0.77

Summary of Potential Ordinary Shares Outstanding Excluded from Computation of Diluted Net Loss Per Ordinary Share


	For the years ended December 31,
	2015		2016		2017
Share issuable upon exercise of share options		904,489		152,500		768,266
Share issuable upon exercise of RSUs		15,001		50,000		—

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2017

Commitments and Contingencies Disclosure [Abstract]

Schedule of Future Minimum Payments under Non-Cancellable Operating Leases

Future minimum payments under non-cancellable operating leases as of December 31, 2017 were as follows:


2018	$	7,671
2019		4,230
2020		2,990
2021		2,262

Total	$	17,153

Related Party Balances and Transactions (Tables)

12 Months Ended

Dec. 31, 2017

Schedule of Related Party Transactions

(1)

Amount due from related parties-current


	As of December 31,
	2016		2017
Hunan Qindao Network Media Technology Co., Ltd. (ii)	$	—	$	5,143
Hangzhou Alimama Technology Co., Ltd.		2		—
Guangzhou UC Network Technology Co., Ltd.		5		—
Guangzhou Aijiuyou Informational Technology Co., Ltd.		81		—

Total	$	88	$	5,143

(ii)

The amount of $5,143 as of December 31, 2017 represented the advance payment of revenue sharing of live video service made to Hunan Qindao Network Media Technology Co., Ltd.

(2)

Amount due to related parties - current


	As of December 31,
	2016		2017
Amount due to ordinary shareholders (iii)	$	5,862	$	5,775
Hunan Qindao Cultural Spread Ltd.		1,281		—
Alibaba Cloud Computing Ltd.		629		—
Shanghai Touch Future Network Technology Co., Ltd.		229		—
Taobao (China) Software Co., Ltd.		116		—
Others		—		29

Total	$	8,117	$	5,804

(iii)

(3)

Sales to related parties


	For the years ended December 31,
	2015		2016		2017
Hangzhou Yihong Advertisement Co., Ltd. (iv)	$	—	$	—	$	2,614
Hangzhou Alimama Technology Co., Ltd. (iv)		6,002		42		342
Guangzhou Aijiuyou Informational Technology Co., Ltd. (v)		—		400		184
Zhejiang Tmall Technology Co., Ltd. (iv)		—		820		74
Shanghai Xisue Network Technology Co., Ltd.		—		922		—
Taobao (China) Software Co., Ltd. (iv)		—		249		—
Others		—		9		2

Total	$	6,002	$	2,442	$	3,216

(iv)

The sales to related parties represented mobile marketing services provided.

(v)

The sales to related parties represented mobile game revenue generated through those game operating companies.

(4)

Purchase from related parties


	For the years ended December 31,
	2015		2016		2017
Hunan Qindao Network Media Technology Co., Ltd. (vi)	$	—	$	—	$	20,639
Alibaba Cloud Computing Ltd. (vii)		322		3,360		11,060
Hunan Qindao Cultural Spread Ltd. (vi)		—		3,929		9,131
Taobao (China) Software Co., Ltd.		—		323		338
Guangzhou Jianyue Information Technology Co., Ltd.		—		—		119
Shanghai Touch future Network Technology Co., Ltd.		—		347		—

Total	$	322	$	7,959	$	41,287

(vi)

The purchases from Hunan Qindao Network Media Technology Co., Ltd. and Hunan Qindao Cultural Spread Ltd. represent the revenue sharing with broadcaster agencies of live video service.

(vii)

The purchase from Alibaba Cloud Computing Ltd. is mainly related to its cloud computing services.

Segment Information (Tables)

12 Months Ended

Dec. 31, 2017

Segment Reporting [Abstract]

Components of Revenues

Components of revenues are presented in the following table:


	For the years ended December 31,
	2015		2016		2017
Live video service	$	1,231	$	376,925	$	1,102,592
Value-added service		58,462		67,603		103,139
Mobile marketing		38,885		66,339		76,178
Mobile games		31,082		35,453		35,619
Other services		4,328		6,778		743

Total	$	133,988	$	553,098	$	1,318,271

Organization and Principal Activities - Additional Information (Detail) $ in Thousands			1 Months Ended			12 Months Ended
	Dec. 16, 2014 shares	Jul. 07, 2011	May 31, 2016	Dec. 31, 2014 shares	Aug. 31, 2014	Dec. 31, 2017 USD ($) asset_group related_party Term shares	Dec. 31, 2017 CNY (¥) asset_group related_party Term shares	Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 USD ($) shares	Nov. 23, 2011 USD ($)
Variable Interest Entity [Line Items]
Date of incorporation						Nov. 23, 2011	Nov. 23, 2011
Share capital \| $										$ 15
Ordinary shares conversion basis						Each Class B ordinary share is convertible into one Class A ordinary share at any time by the holder thereof, while Class A ordinary shares are not convertible to Class B ordinary shares under any circumstances.	Each Class B ordinary share is convertible into one Class A ordinary share at any time by the holder thereof, while Class A ordinary shares are not convertible to Class B ordinary shares under any circumstances.
Ordinary shares, new issues						9,476,874	9,476,874	5,197,032	5,995,293
Percentage of VIEs revenues to the consolidated net revenues						100.00%	100.00%	100.00%	100.00%
Percentage of VIEs assets to the consolidated total assets						18.40%	18.40%	16.30%
Percentage of VIEs liability to the consolidated total liabilities						62.10%	62.10%	66.40%
Number of consolidated VIE's assets that are collateral for the VIE's obligations \| asset_group						0	0
VIEs creditors having recourse to general credit of the Company \| related_party						0	0
Number of terms under arrangement with VIEs to provide financial support \| Term						0	0
Class A Common Stock [Member]
Variable Interest Entity [Line Items]
Ordinary shares, voting rights						One vote per share	One vote per share
Ordinary shares, new issues	45,688,888			45,688,888
Class B Common Stock [Member]
Variable Interest Entity [Line Items]
Ordinary shares, voting rights						Ten votes per share	Ten votes per share
IPO [Member] \| Class A Common Stock [Member]
Variable Interest Entity [Line Items]
Ordinary shares, new issues	36,800,000			36,800,000
Convertible preferred stock shares converted				200,718,811
Private Placement [Member] \| Class A Common Stock [Member]
Variable Interest Entity [Line Items]
Ordinary shares, new issues	8,888,888			8,888,888
Mr. Yan Tang [Member]
Variable Interest Entity [Line Items]
Percentage ownership in share capital										65.00%
Mr. Yong Li [Member]
Variable Interest Entity [Line Items]
Percentage ownership in share capital										20.00%
Mr. Xiaoliang Lei [Member]
Variable Interest Entity [Line Items]
Percentage ownership in share capital										8.00%
Mr. Zhiwei Li [Member]
Variable Interest Entity [Line Items]
Percentage ownership in share capital										7.00%
Business Operations Agreement [Member]
Variable Interest Entity [Line Items]
Effective years of agreement						10 years	10 years
Exclusive Cooperation Agreements and Supplemental Agreements [Member]
Variable Interest Entity [Line Items]
Service fee \| $						$ 662,503		$ 319,018	$ 112,043
Momo Technology HK Company Limited [Member]
Variable Interest Entity [Line Items]
Percentage of economic ownership						100.00%	100.00%
Beijing Momo Information Technology Co., Ltd. [Member]
Variable Interest Entity [Line Items]
Percentage of economic ownership						100.00%	100.00%
Beijing Momo Information Technology Co., Ltd. [Member] \| Exclusive Cooperation Agreements and Supplemental Agreements [Member]
Variable Interest Entity [Line Items]
Effective years of agreement					10 years
Beijing Momo Technology Co., Ltd. [Member]
Variable Interest Entity [Line Items]
Maximum call option agreement threshold value \| ¥							¥ 500,000
Beijing Momo Technology Co., Ltd. [Member] \| Mr. Yan Tang [Member]
Variable Interest Entity [Line Items]
Capital contribution percentage, subsidiaries		65.00%
Beijing Momo Technology Co., Ltd. [Member] \| Mr. Yong Li [Member]
Variable Interest Entity [Line Items]
Capital contribution percentage, subsidiaries		20.00%
Beijing Momo Technology Co., Ltd. [Member] \| Mr. Xiaoliang Lei [Member]
Variable Interest Entity [Line Items]
Capital contribution percentage, subsidiaries		8.00%
Beijing Momo Technology Co., Ltd. [Member] \| Mr. Zhiwei Li [Member]
Variable Interest Entity [Line Items]
Capital contribution percentage, subsidiaries		7.00%
Chengdu Momo Technology Company Limited Investment [Member] \| Exclusive Cooperation Agreements and Supplemental Agreements [Member]
Variable Interest Entity [Line Items]
Effective years of agreement					10 years
Tianjin Heer Technology Co. Ltd [Member] \| Exclusive Cooperation Agreements and Supplemental Agreements [Member]
Variable Interest Entity [Line Items]
Effective years of agreement			10 years

Organization and Principal Activities - Schedule of Subsidiaries, VIE and VIE's Subsidiaries (Detail)

12 Months Ended

Dec. 31, 2017

Momo Technology HK Company Limited [Member]

Variable Interest Entity [Line Items]

Date of incorporation or acquisition

Dec. 05, 2011

Place of Incorporation

Hong Kong

Percentage of economic ownership

100.00%

Beijing Momo Information Technology Co., Ltd. [Member]

Variable Interest Entity [Line Items]

Date of incorporation or acquisition

Mar. 09, 2012

Place of Incorporation

PRC

Percentage of economic ownership

100.00%

Momo Technology Overseas Holding Company Limited [Member]

Variable Interest Entity [Line Items]

Date of incorporation or acquisition

Mar. 05, 2014

Place of Incorporation

BVI

Percentage of economic ownership

100.00%

Momo Information Technologies Corp. [Member]

Variable Interest Entity [Line Items]

Date of incorporation or acquisition

Mar. 07, 2014

Place of Incorporation

Percentage of economic ownership

100.00%

Beijing Momo Technology Co., Ltd. [Member]

Variable Interest Entity [Line Items]

Date of incorporation or acquisition

Jul. 07, 2011

^[1]

Place of Incorporation

PRC

^[1]

Chengdu Momo Technology Co., Ltd. [Member]

Variable Interest Entity [Line Items]

Date of incorporation or acquisition

May 09, 2013

^[1]

Place of Incorporation

PRC

^[1]

Shanghai Momo Technology Co., Ltd. [Member]

Variable Interest Entity [Line Items]

Date of incorporation or acquisition

Jan. 19, 2015

^[1]

Place of Incorporation

PRC

^[1]

Chengdu Biyou Technology Co., Ltd. [Member]

Variable Interest Entity [Line Items]

Date of incorporation or acquisition

Oct. 16, 2015

^[1]

Place of Incorporation

PRC

^[1]

Tianjin Heer Technology Co., Ltd [Member]

Variable Interest Entity [Line Items]

Date of incorporation or acquisition

Mar. 07, 2016

^[1]

Place of Incorporation

PRC

^[1]

Momo Pictures Co. Ltd. [Member]

Variable Interest Entity [Line Items]

Date of incorporation or acquisition

Nov. 11, 2016

^[1]

Place of Incorporation

PRC

^[1]

QOOL Media Co., Ltd [Member]

Variable Interest Entity [Line Items]

Date of incorporation or acquisition

Nov. 16, 2016

^[1]

Place of Incorporation

PRC

^[1]

Zhejiang Shengdian Digital Network Co., Ltd. [Member]

Variable Interest Entity [Line Items]

Date of incorporation or acquisition

Mar. 31, 2017

^[1]

Place of Incorporation

PRC

^[1]

Beijing Santi Cloud Union Technology Co., Ltd. [Member]

Variable Interest Entity [Line Items]

Date of incorporation or acquisition

Jun. 30, 2017

^[1]

Place of Incorporation

PRC

^[1]

Loudi Momo Technology Co., Ltd. [Member]

Variable Interest Entity [Line Items]

Date of incorporation or acquisition

Jul. 17, 2017

^[1]

Place of Incorporation

PRC

^[1]

Changsha Heer Network Co., Ltd. [Member]

Variable Interest Entity [Line Items]

Date of incorporation or acquisition

Sep. 20, 2017

^[1]

Place of Incorporation

PRC

^[1]

Beijing Santi Cloud Time Technology Co. Ltd. [Member]

Variable Interest Entity [Line Items]

Date of incorporation or acquisition

Sep. 26, 2017

^[1]

Place of Incorporation

PRC

^[1]

[1]	These entities are controlled by the Company pursuant to the contractual arrangements disclosed below.

Organization and Principal Activities - Schedule of Amounts and Balances of VIE Included in Consolidated Financial Statements After Elimination of Intercompany Balances and Transactions (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Variable Interest Entity [Line Items]
Cash and cash equivalents	$ 685,827	$ 257,564	$ 169,469	$ 450,968
Accounts receivable, net of allowance for doubtful accounts of $nil and $90 as of December 31, 2016 and 2017, respectively	39,597	36,078
Amount due from related parties	5,143	88
Prepaid expenses and other current assets	82,717	32,592
Deferred tax assets, current		72
Short-term investment	1,614
Total current assets	1,188,692	720,153
Property and equipment, net	39,762	13,932
Intangible assets	7,462
Rental deposits	2,651	920
Other non-current assets	8,495	2,593
Long term investments	44,337	31,932
Deferred tax assets, non-current	7,197	208
Goodwill	3,401
Total assets	1,301,997	769,738
Accounts payable	74,535	40,457
Deferred revenue	64,865	41,277
Accrued expenses and other current liabilities	87,809	39,965
Amounts due to related parties	5,804	8,117
Total current liabilities	260,046	133,697
Deferred tax liabilities, non-current	1,866
Total liabilities	264,217	135,719
Net revenues	1,318,271	553,098	133,988
Net income	318,566	145,250	13,697
Beijing Momo Technology Co., Ltd. [Member]
Variable Interest Entity [Line Items]
Cash and cash equivalents	63,110	36,855
Accounts receivable, net of allowance for doubtful accounts of $nil and $90 as of December 31, 2016 and 2017, respectively	39,597	36,078
Amount due from related parties	5,143	88
Prepaid expenses and other current assets	57,056	20,613
Deferred tax assets, current		72
Short-term investment	1,614
Total current assets	166,520	93,706
Property and equipment, net	8,080	1,854
Intangible assets	7,462
Rental deposits	1,609	325
Other non-current assets	7,685	2,593
Long term investments	43,333	26,541
Deferred tax assets, non-current	1,062	208
Goodwill	3,401
Total assets	239,152	125,227
Accounts payable	54,937	36,812
Deferred revenue	64,788	41,277
Accrued expenses and other current liabilities	30,802	6,632
Amounts due to related parties	29	1,510
Income tax payable	11,765	3,881
Total current liabilities	162,321	90,112
Deferred tax liabilities, non-current	1,866
Total liabilities	164,187	90,112
Net revenues	1,318,271	553,098	133,988
Net income	724,880	340,366	118,404
Net cash provided by operating activities	740,683	360,433	124,786
Net cash used in investing activities	(25,810)	$ (11,027)	$ (19,435)
Net cash provided by financing activities	$ 73

Organization and Principal Activities - Schedule of Amounts and Balances of VIE Included in Consolidated Financial Statements After Elimination of Intercompany Balances and Transactions (Parenthetical) (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Variable Interest Entity [Line Items]
Allowance for doubtful accounts	$ 90	$ 0
Beijing Momo Technology Co., Ltd. [Member]
Variable Interest Entity [Line Items]
Allowance for doubtful accounts	$ 90	$ 0

Significant Accounting Policies - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) Agreement Customer Product	Dec. 31, 2016 USD ($) Agreement Customer Product	Dec. 31, 2015 USD ($) Customer	Dec. 31, 2014 USD ($)
Accounting Policies [Line Items]
Bank deposits maturity	3 months
Cash and cash equivalents	$ 685,827	$ 257,564	$ 169,469	$ 450,968
Net revenues recognized	1,318,271	553,098	133,988
Other operating income	23,379	406	713
Value added tax incurred	120,256	55,353	16,951
Income tax expenses	65,980	5,136	92
Advertising expense	$ 153,425	55,188	27,793
Minimum [Member]
Accounting Policies [Line Items]
Percentage of ownership, equity method investment	20.00%
Maximum [Member]
Accounting Policies [Line Items]
Percentage of ownership, equity method investment	50.00%
Membership Subscription [Member]
Accounting Policies [Line Items]
Contract period, minimum	1 month
Contract period, maximum	1 year
Mobile Marketing [Member]
Accounting Policies [Line Items]
Net revenues recognized	$ 76,178	$ 66,339	38,885
Self Developed Mobile Game [Member]
Accounting Policies [Line Items]
Number of games \| Product	8	6
Self Developed Mobile Game [Member] \| Minimum [Member]
Accounting Policies [Line Items]
Estimated usage life of product/service	56 days	20 days
Self Developed Mobile Game [Member] \| Maximum [Member]
Accounting Policies [Line Items]
Estimated usage life of product/service	79 days	110 days
Mobile Games [Member]
Accounting Policies [Line Items]
Net revenues recognized	$ 35,619	$ 35,453	31,082
Number of games \| Agreement	6	6
Mobile Games [Member] \| Minimum [Member]
Accounting Policies [Line Items]
Estimated usage life of product/service	20 days	20 days
Mobile Games [Member] \| Maximum [Member]
Accounting Policies [Line Items]
Estimated usage life of product/service	101 days	99 days
Live Video Service [Member]
Accounting Policies [Line Items]
Net revenues recognized	$ 1,102,592	$ 376,925	1,231
Value-added Services [Member]
Accounting Policies [Line Items]
Net revenues recognized	103,139	67,603	58,462
Government Subsidies
Accounting Policies [Line Items]
Other operating income	$ 20,977	$ 293	$ 0
User Concentration Risk [Member] \| Accounts Receivable [Member]
Accounting Policies [Line Items]
Number of users or advertising customer accounted for 10% or more of total revenues \| Customer	0	0
User Concentration Risk [Member] \| Revenues [Member]
Accounting Policies [Line Items]
Number of users or advertising customer accounted for 10% or more of total revenues \| Customer	0	0	0
China, Yuan Renminbi
Accounting Policies [Line Items]
Cash and cash equivalents	$ 632,572	$ 245,853

Significant Accounting Policies - Schedule of Third-Party Application Stores and Other Payment Channels Accounting Receivables (Detail) - Accounts Receivable [Member] - Credit Concentration Risk [Member]	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Third-party Payment Channel A [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	23.00%	40.00%
Third-party Payment Channel B [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	21.00%
Third-party Payment Channel C [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	19.00%	15.00%
Third-party Payment Channel D [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	5.00%	22.00%

Significant Accounting Policies - Schedule of Estimated Useful Lives of Property and Equipment (Detail)	12 Months Ended
	Dec. 31, 2017
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	3 years
Vehicles [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	5 years
Leasehold Improvement [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	Shorter of the lease term or estimated useful lives
Minimum [Member] \| Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	3 years
Maximum [Member] \| Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	5 years

Significant Accounting Policies - Schedule of Estimated Useful Lives of Intangible Assets (Detail)	12 Months Ended
	Dec. 31, 2017
Copyrights [Member]
Finite-Lived Intangible Liabilities [Line Items]
Finite-Lived Intangible Asset, Useful Life	1 year
Minimum [Member] \| Licenses [Member]
Finite-Lived Intangible Liabilities [Line Items]
Finite-Lived Intangible Asset, Useful Life	3 years 2 months 12 days
Maximum [Member] \| Licenses [Member]
Finite-Lived Intangible Liabilities [Line Items]
Finite-Lived Intangible Asset, Useful Life	10 years

Accounts Receivable, Net - Schedule of Accounts Receivable, Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Additional Disclosures [Abstract]
Accounts receivable	$ 39,687	$ 36,078
Less: allowance for doubtful accounts	(90)	0
Accounts receivable, net	$ 39,597	$ 36,078

Prepaid Expenses and Other Current Assets - Schedule of Prepaid Expenses and Other Current Assets (Detail) - USD ($)
$ in Thousands

Dec. 31, 2017

Dec. 31, 2016

Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]

Deposit at a third-party payment channel

^[1]

$ 29,239

$ 4,845

Advance to suppliers

^[2]

21,521

5,331

Interest receivable

8,441

4,821

Prepaid income tax and other expenses

8,069

2,964

Deferred platform commission cost

4,292

4,571

Input VAT

^[3]

3,714

2,968

Game promotions fees paid on behalf of game developers

2,742

2,250

Advance to game developers

924

1,550

Others

3,775

3,292

Prepaid expenses and other current assets

$ 82,717

$ 32,592

[1]	Deposit at a third party payment channel is the cash deposited in a third party payment channel by the Group for the broadcasters to withdraw their revenue sharing and the customer payment to the Group's account through a third party payment channel.
[2]	Advance to suppliers were primarily for advertising fees and live video broadcasting service fees.
[3]	Input VAT mainly occurred from the purchasing of goods for other services, property and equipment and advertising activities. It is subject to verification by related tax authorities before offsetting the VAT output.

Long Term Investments - Summary of Equity and Cost Method Investments (Detail) - USD ($)
$ in Thousands

Dec. 31, 2017

Dec. 31, 2016

Aug. 18, 2015

Feb. 13, 2015

Investment [Line Items]

Long term Investments

$ 44,337

$ 31,932

Hunan Qindao Cultural Spread Ltd. [Member]

Investment [Line Items]

Cost method investments

^[1]

4,611

Available-for-sale investments

^[1]

2,880

Other Cost Method Investment [Member]

Investment [Line Items]

Cost method investments

^[2]

7,655

1,834

Xish International Limited [Member]

Investment [Line Items]

Available-for-sale investments

^[3]

4,386

Jingwei Chuangteng (Hangzhou) L.P. [Member]

Investment [Line Items]

Equity method investments

^[4]

7,419

4,191

Beijing Autobot Venture Capital L.P. [Member]

Investment [Line Items]

Equity method investments

8,478

^[5]

6,736

^[5]

$ 4,823

Hangzhou Aqua Ventures Investment Management L.P. [Member]

Investment [Line Items]

Equity method investments

12,986

^[6]

9,187

^[6]

$ 7,930

Other Equity Method Investments [Member]

Investment [Line Items]

Equity method investments

^[2]

$ 3,188

$ 2,718

[1]	On June 8, 2016, the Group entered into a share purchase agreement to acquire 16.0% preferred shares of Hunan Qindao Cultural Spread Ltd. ("Qindao") for a total consideration of $4,441, which was fully paid off as of December 31, 2017. The investment was classified as available-for-sale security as the Group determined that the preferred shares were debt securities due to the redemption option available to the investor and measured the investment subsequently at fair value. No unrealized holding gains was reported in other comprehensive income for the year ended December 31, 2016. On July 7, 2017, the Group signed a supplemental agreement with Qindao to waive the redemption right. The investment was reclassified to cost method investment as a result of the supplemental agreement. The Group recorded $nil of accumulated unrealized holding gain through earnings.
[2]	Others represent equity method investments or cost method investments that are individually insignificant.
[3]	On January 21, 2016, the Group entered into a preferred share subscription agreement to acquire 17.3% equity of Xish International Limited ("Xish") for a total consideration of $9,000, which had been paid as of December 31, 2016. The investment was classified as available-for-sale security as the Group determined that the preferred shares were debt securities due to the redemption option available to the investor and measured the investment subsequently at fair value. The Group recognized an impairment loss of $4,614 and $4,386 during the year ended December 31, 2016 and 2017, respectively. Please refer to Note 9 for additional information on the fair value measurement related to the impairment loss.
[4]	On January 9, 2015, the Group entered into a partnership agreement to subscribe partnership interest, as a limited partner, in Jingwei Chuangteng (Hangzhou) L.P. ("Jingwei"). According to the partnership agreement, the Group committed to subscribe 4.9% partnership interest in Jingwei for $4,744, which had been paid as of December 31, 2017. Due to Jingwei's further rounds of financing, the Group's partnership interest was diluted to 2.4% as of December 31, 2016 and 2017. The Group recognized its share of partnership profit in Jingwei of $366, $633 and $1,717 during the year ended December 31, 2015, 2016 and 2017, respectively.
[5]	On February 13, 2015, the Group entered into a partnership agreement to subscribe partnership interest, as a limited partner, in Beijing Autobot Venture Capital L.P. ("Autobot"). According to the partnership agreement, the Group committed to subscribe 31.9% partnership interest in Autobot for $4,823. Autobot had further rounds of financing, of which the Group subscribed for $1,529. Due to Autobot's further round of financing, the Group's partnership interest was diluted to 26.7% as of December 31, 2016 and 2017. The committed subscription and further round of financing subscription amount, $6,352, was paid as of December 31, 2016. The Group recognized its share of partnership profit in Autobot of $274, $771 and $1,239 during the year ended December 31, 2015, 2016 and 2017, respectively.
[6]	On August 18, 2015, the Group entered into a partnership agreement to subscribe partnership interest, as a limited partner, in Hangzhou Aqua Ventures Investment Management L.P. ("Aqua"). According to the partnership agreement, the Group committed to subscribe 42.7% partnership interest for $7,930. The committed subscription amount had been fully paid as of December 31, 2016. The Group recognized its share of partnership profit in Aqua of $89, $2,134 and $3,088 during the years ended December 31, 2015, 2016 and 2017, respectively.

Long Term Investments - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Investment [Line Items]
Impairment loss on long-term investments	$ 4,386	$ 5,765
Other Cost Method Investment [Member]
Investment [Line Items]
Impairment loss on long-term investments	0	(965)	$ 0
Other Equity Method Investments [Member]
Investment [Line Items]
Impairment loss on long-term investments	$ 0	$ (186)	$ 0

Long Term Investments - Summary of Equity and Cost Method Investments (Parenthetical) (Detail) - USD ($)

12 Months Ended

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Jul. 07, 2017

Jun. 08, 2016

Jan. 21, 2016

Aug. 18, 2015

Feb. 13, 2015

Jan. 09, 2015

Investment [Line Items]

Share of income (loss) on equity method investments

$ 5,889,000

$ 3,471,000

$ 370,000

Impairment loss on long-term investments

4,386,000

5,765,000

Xish International Limited [Member]

Investment [Line Items]

Percentage of shares acquired recorded as available for sale debt security

17.30%

Share purchase agreement, consideration paid

9,000,000

Impairment loss on long-term investments

4,386,000

4,614,000

Jingwei Chuangteng (Hangzhou) L.P. [Member]

Investment [Line Items]

Equity method investments

^[1]

$ 7,419,000

$ 4,191,000

Percentage of ownership

2.40%

4.90%

Share of income (loss) on equity method investments

$ 1,717,000

$ 633,000

366,000

Payment of equity method investment

4,744,000

Beijing Autobot Venture Capital L.P. [Member]

Investment [Line Items]

Equity method investments

$ 8,478,000

^[2]

$ 6,736,000

^[2]

$ 4,823,000

Equity method investments, further financing

1,529,000

Percentage of ownership

26.70%

31.90%

Share of income (loss) on equity method investments

$ 1,239,000

$ 771,000

274,000

Payment of equity method investment

6,352,000

Hangzhou Aqua Ventures Investment Management L.P. [Member]

Investment [Line Items]

Equity method investments

12,986,000

^[3]

9,187,000

^[3]

$ 7,930,000

Percentage of ownership

42.70%

Share of income (loss) on equity method investments

3,088,000

2,134,000

$ 89,000

Hunan Qindao Cultural Spread Ltd. [Member]

Investment [Line Items]

Percentage of shares acquired recorded as available for sale debt security

16.00%

Unrealized holding gains

$ 0

Payments to acquire available-for-sale securities, equity

$ 4,441,000

Investment due to lack of ability to exercise significant influence

$ 0

[1]	On January 9, 2015, the Group entered into a partnership agreement to subscribe partnership interest, as a limited partner, in Jingwei Chuangteng (Hangzhou) L.P. ("Jingwei"). According to the partnership agreement, the Group committed to subscribe 4.9% partnership interest in Jingwei for $4,744, which had been paid as of December 31, 2017. Due to Jingwei's further rounds of financing, the Group's partnership interest was diluted to 2.4% as of December 31, 2016 and 2017. The Group recognized its share of partnership profit in Jingwei of $366, $633 and $1,717 during the year ended December 31, 2015, 2016 and 2017, respectively.
[2]	On February 13, 2015, the Group entered into a partnership agreement to subscribe partnership interest, as a limited partner, in Beijing Autobot Venture Capital L.P. ("Autobot"). According to the partnership agreement, the Group committed to subscribe 31.9% partnership interest in Autobot for $4,823. Autobot had further rounds of financing, of which the Group subscribed for $1,529. Due to Autobot's further round of financing, the Group's partnership interest was diluted to 26.7% as of December 31, 2016 and 2017. The committed subscription and further round of financing subscription amount, $6,352, was paid as of December 31, 2016. The Group recognized its share of partnership profit in Autobot of $274, $771 and $1,239 during the year ended December 31, 2015, 2016 and 2017, respectively.
[3]	On August 18, 2015, the Group entered into a partnership agreement to subscribe partnership interest, as a limited partner, in Hangzhou Aqua Ventures Investment Management L.P. ("Aqua"). According to the partnership agreement, the Group committed to subscribe 42.7% partnership interest for $7,930. The committed subscription amount had been fully paid as of December 31, 2016. The Group recognized its share of partnership profit in Aqua of $89, $2,134 and $3,088 during the years ended December 31, 2015, 2016 and 2017, respectively.

Property and Equipment, Net - Schedule of Property and Equipment, Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Less: accumulated depreciation	$ (30,566)	$ (18,844)
Exchange difference	1,979	1,812
Total	39,762	13,932
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	45,580	23,763
Office Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	12,214	4,370
Vehicles [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	189	31
Leasehold Improvement [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 10,366	$ 2,800

Intangible Assets, Net - Schedule of Intangible Assets (Detail)
$ in Thousands

Dec. 31, 2017

USD ($)

Finite-Lived Intangible Liabilities [Line Items]

Less: accumulated amortization and impairment

$ (905)

Exchange difference

(25)

Intangible assets, net

7,462

Licenses [Member]

Finite-Lived Intangible Liabilities [Line Items]

Intangible assets, gross

8,059

^[1]

Game copyright [Member]

Finite-Lived Intangible Liabilities [Line Items]

Intangible assets, gross

$ 333

[1]	* Licenses mainly consist of the Internet Audio/Video Program Transmission License, which is a requisite permit according to government regulations for the Group's business operation such as live video service.

Intangible Assets, Net - Schedule of Future Amortization Expense (Detail) $ in Thousands	Dec. 31, 2017 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2018	$ 881
2019	881
2020	881
2021	774
2022	771
Thereafter	3,274
Intangible assets, net	$ 7,462

Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Accrued payroll and welfare	$ 34,523	$ 18,982
Payable for advertisement	18,783	9,871
Balance of users' virtual accounts	14,175	779
Other tax payables	9,457	4,694
Accrued professional services fee	3,417	1,438
VAT payable	1,543	1,919
Others	5,911	2,282
Total	$ 87,809	$ 39,965

Fair Value - Schedule of Assets Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	$ 0	$ 7,266
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	685,827	257,564
Available-for-sale investments		7,266
Total	685,827	264,830
Fair Value, Measurements, Recurring [Member] \| Quoted Prices in Active Market for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	685,827	257,564
Total	$ 685,827	257,564
Fair Value, Measurements, Recurring [Member] \| Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments		7,266
Total		$ 7,266

Fair Value - Schedule of Reconciliation of Fair Value Measurement of Available-for-Sale Investments Using Significant Unobservable Inputs on a Recurring Basis (Detail)
$ in Thousands

12 Months Ended

Dec. 31, 2017

USD ($)

Fair Value Disclosures [Abstract]

Beginning balance

$ 7,266

Purchase

1,458

Other-than-temporary loss recognized

(4,386)

Reclassification to cost method investment

(4,611)

^[1]

Foreign exchange difference

273

Ending balance

$ 0

[1]	The investment in Qindao was reclassified from available-for-sale investment to cost method investment as of result of the waiver of redemption right in July 2017. Please refer to Note 5 for additional information on the reclassification.

Fair Value - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment loss on assets	$ 4,386	$ 5,765
Other Cost and Equity Method Investment [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment loss on assets	$ 0	$ 1,151

Income Taxes - Additional Information (Detail) - USD ($)		1 Months Ended	12 Months Ended
	Dec. 31, 2017	Aug. 31, 2014	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Contingency [Line Items]
Income tax expense			$ 65,980,000	$ 5,136,000	$ 92,000
Significant unrecognized tax benefit	$ 0		0	0	0
Interest related to penalties			0	0	0
Significant impact on the unrecognized tax benefits for next twelve months	0		0	$ 0	$ 0
Beijing Momo IT, Beijing Momo and Chengdu Momo [Member]
Income Tax Contingency [Line Items]
Tax loss carry forward	5,431,000		5,431,000
Momo Information Technologies Corp. [Member]
Income Tax Contingency [Line Items]
Tax loss carry forward	8,985,000		$ 8,985,000
Tax loss carry forward period			20 years
Momo Technology HK Company Limited [Member]
Income Tax Contingency [Line Items]
Tax loss carry forward	$ 178,000		$ 178,000
Earliest Tax Year [Member]
Income Tax Contingency [Line Items]
Tax years subject to tax audits			2014
Earliest Tax Year [Member] \| Beijing Momo IT, Beijing Momo and Chengdu Momo [Member]
Income Tax Contingency [Line Items]
Tax loss carry forward, expiration date			Dec. 31, 2020
Latest Tax Year [Member]
Income Tax Contingency [Line Items]
Tax years subject to tax audits			2016
Latest Tax Year [Member] \| Beijing Momo IT, Beijing Momo and Chengdu Momo [Member]
Income Tax Contingency [Line Items]
Tax loss carry forward, expiration date			Dec. 31, 2022
United States [Member] \| Momo Information Technologies Corp. [Member]
Income Tax Contingency [Line Items]
Taxable income			$ 0
Income tax expense			$ 0
Hong Kong [Member] \| Beneficial Owner [Member] \| Minimum [Member]
Income Tax Contingency [Line Items]
Equity interest in a PRC-resident enterprise	25.00%		25.00%
Hong Kong [Member] \| Momo Technology HK Company Limited [Member]
Income Tax Contingency [Line Items]
Profit tax rate			16.50%
PRC [Member]
Income Tax Contingency [Line Items]
Income tax expense	$ 0
Withholding income tax rate for dividends distributed by the PRC subsidiaries			10.00%
PRC statutory tax rate			25.00%	25.00%	25.00%
Dividend declared	$ 0		$ 0
PRC [Member] \| Chengdu Momo Technology Company Limited Investment [Member]
Income Tax Contingency [Line Items]
Percentage of reduced tax rate			15.00%
PRC [Member] \| Beneficial Owner [Member]
Income Tax Contingency [Line Items]
Withholding income tax rate for dividends distributed by the PRC subsidiaries			5.00%
PRC [Member] \| 2015 - 2016 [Member] \| Beijing Momo Information Technology Co., Ltd. [Member]
Income Tax Contingency [Line Items]
Tax exemption period		2 years
PRC [Member] \| 2017 - 2019 [Member] \| Beijing Momo Information Technology Co., Ltd. [Member]
Income Tax Contingency [Line Items]
Reduced tax rate period		3 years
Percentage of reduced tax rate		12.50%
PRC [Member] \| Other Entities [Member]
Income Tax Contingency [Line Items]
Effective income tax rate			25.00%

Income Taxes - Components of Group's Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current deferred tax assets:
Impairment of loss on long term investments		$ 72
Less: valuation allowance	$ 0	0
Current deferred tax assets, net		72
Non-current deferred tax assets:
Advertising expense	5,957
Net operating tax losses carry-forward	3,964	2,852
Impairment on long term investments and game copyright	400	208
Accrued expenses	840
Less: valuation allowance	(3,964)	(2,852)
Non-current deferred tax assets, net	7,197	$ 208
Non-current deferred tax liabilities:
Intangible assets acquired	1,866
Non-current deferred tax assets, net	$ 1,866

Income Taxes - Schedule of Reconciliation between Income Tax Expense to Income before Income Taxes and Actual Provision for Income Tax (Detail) - USD ($)		12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes And Tax Related [Line Items]
Net income before provision for income tax		$ 378,115,000	$ 146,915,000	$ 13,419,000
Income tax expense at statutory tax rate		94,529,000	36,729,000	3,355,000
Permanent differences		(66,000)	(75,000)	(144,000)
Change in valuation allowance		1,112,000	(2,680,000)	(2,315,000)
Effect of income tax rate difference in other jurisdictions		11,857,000	7,941,000	2,754,000
Effect of tax holidays and preferential tax rates		(41,452,000)	(36,779,000)	(3,558,000)
Provision for income tax		$ 65,980,000	$ 5,136,000	$ 92,000
PRC [Member]
Income Taxes And Tax Related [Line Items]
PRC statutory tax rate		25.00%	25.00%	25.00%
Provision for income tax	$ 0

Income Taxes - Increase in Income Tax Expenses and Net Income Per Share Amounts (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Increase in income tax expenses	$ 41,452	$ 36,779	$ 3,558
Earnings per share after increase in income tax expenses - basic	$ 0.70	$ 0.28	$ 0.03
Earnings per share after increase in income tax expenses - diluted	$ 0.67	$ 0.27	$ 0.03

Ordinary Shares - Additional Information (Detail) $ / shares in Units, $ in Thousands				1 Months Ended		12 Months Ended
	Dec. 16, 2014 shares	Apr. 22, 2014 USD ($) shares	Sep. 12, 2012 shares	Dec. 31, 2014 shares	May 31, 2014 USD ($)	Dec. 31, 2017 USD ($) $ / shares shares	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 shares	Nov. 28, 2014 shares	Oct. 08, 2013 shares	Jul. 13, 2012 shares	Jun. 11, 2012 shares	Apr. 30, 2012 shares	Apr. 12, 2012 shares	Nov. 23, 2011 $ / shares shares
Class of Stock [Line Items]
Ordinary shares, shares authorized		799,281,189	371,684,330						1,000,000,000	835,675,688	366,789,830	426,747,470		446,545,450	500,000,000
Ordinary shares, shares issued													147,000,000		147,000,000
Ordinary shares, par value \| $ / shares															$ 0.0001
Shares authorized		1,000,000,000								1,000,000,000				500,000,000
Convertible redeemable preferred shares, shares authorized		200,718,811								164,324,312				53,454,550
Stock split ratio for ordinary shares			10
Amounts due to related parties, current \| $						$ 5,804	$ 8,117
Issuance of ordinary shares in connection with exercise of options and vesting of share units						9,476,874	5,197,032	5,995,293
Class A Common Stock [Member]
Class of Stock [Line Items]
Ordinary shares, shares authorized						800,000,000	800,000,000		800,000,000
Ordinary shares, shares issued						314,060,843	292,062,065
Ordinary shares, par value \| $ / shares						$ 0.0001	$ 0.0001
Issuance of ordinary shares in connection with exercise of options and vesting of share units	45,688,888			45,688,888
Convertible preferred stock shares converted to ordinary shares	200,718,811
Ordinary shares, shares outstanding						314,060,843	292,062,065
Class A Common Stock [Member] \| IPO [Member]
Class of Stock [Line Items]
Issuance of ordinary shares in connection with exercise of options and vesting of share units	36,800,000			36,800,000
Class A Common Stock [Member] \| Private Placement [Member]
Class of Stock [Line Items]
Issuance of ordinary shares in connection with exercise of options and vesting of share units	8,888,888			8,888,888
Class B Common Stock [Member]
Class of Stock [Line Items]
Ordinary shares, shares authorized						100,000,000	100,000,000		100,000,000
Ordinary shares, shares issued						84,364,466	96,886,370
Ordinary shares, par value \| $ / shares						$ 0.0001	$ 0.0001
Ordinary shares, shares outstanding						84,364,466	96,886,370
Undesignated Ordinary Shares [Member]
Class of Stock [Line Items]
Ordinary shares, shares authorized									100,000,000
Common Stock [Member]
Class of Stock [Line Items]
Number of shares donated to the company		15,651,589
Amounts due to related parties, current \| $						$ 5,775
Accrued expenses and other current liabilities \| $						$ 675
Issuance of ordinary shares in connection with exercise of options and vesting of share units						9,476,874	5,197,032	5,995,293
Ordinary shares, shares outstanding				377,756,110		398,425,309	388,948,435	383,751,403
Dividend Declared [Member] \| Common Stock [Member]
Class of Stock [Line Items]
Dividend amount \| $		$ 64,494
Dividend Paid [Member] \| Common Stock [Member]
Class of Stock [Line Items]
Dividend amount \| $					$ 58,044
Dividend payable date					2014-05

Share-Based Compensation - Additional Information (Detail) - USD ($)						1 Months Ended				12 Months Ended
	Mar. 07, 2017	May 17, 2016	Jan. 03, 2015	Dec. 11, 2014	May 15, 2014	Jul. 31, 2016	May 31, 2015	Nov. 30, 2014	Apr. 30, 2012	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Nov. 23, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options vested										14,743,283
Options expected to vest										11,114,843
Options expected to vest, weighted-average exercise price										$ 0.0036
Options expected to vest, Aggregate intrinsic value										$ 136,006,000	$ 137,765,000
Weighted average fair value per option at grant date, Granted										$ 17.41	$ 6.24	$ 5.93
Total intrinsic value of options exercised										$ 154,233,000	$ 45,581,000	$ 45,885,000
Total fair value of options vested										$ 37,979,000	27,171,000	13,680,000
Number of options, Forfeited/Canceled										981,527
Share-based compensation										$ 49,657,000	$ 31,706,000	17,382,000
Weighted average remaining contractual term options outstanding										7 years 4 months 24 days	7 years 7 months 17 days
Number of options, granted										5,771,226
Ordinary shares, shares issued									147,000,000					147,000,000
Ordinary shares, par value														$ 0.0001
Class A Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ordinary shares, shares issued										314,060,843	292,062,065
Ordinary shares, par value										$ 0.0001	$ 0.0001
Non-Vested Restricted Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation										$ 0	$ 52,000	$ 180,000
Unrecognized compensation expense										$ 0
Ordinary shares, shares issued					131,348,411				147,000,000
Modification of vesting of shares, description										The Company shall be entitled to repurchase 50% and 25% of such shares in the case that founders terminate their employments with the Company before April 17, 2015 and during the period from April 17, 2015 to April 17, 2016, respectively, at a price of US$0.0001 per share or the lowest price permitted under applicable laws. Therefore, the Company considered that 50% of the total restricted shares were vested immediately on the amendment date and 25% shall be vested annually on April 17 in the next two years ending April 17, 2016. Before the modification date, May 15, 2014, there were 131,348,411 ordinary shares, of which 45,937,500 were unvested restricted shares. As the result of modification, 19,736,705 vested ordinary shares were classified to unvested restricted shares on the modification date and the corresponding compensation costs for these unvested restricted shares were amortized over the remaining service period.
Unvested restricted shares					45,937,500							28,625,378	57,250,756
Unvested restricted shares, modification					19,736,705							0
Ordinary shares, par value					$ 0.0001
Fair value of RSUs, per share										$ 0.01
Fair value of RSUs										$ 1,470,000
Total fair value of non-vested restricted shares vested										0	286,000	$ 286,000
Non-Vested Restricted Shares [Member] \| Share-based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based payment vesting percentage					50.00%				25.00%
Non-Vested Restricted Shares [Member] \| Share-based Compensation Award, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, vesting period					2 years				36 months
Share based payment vesting percentage					25.00%				75.00%
RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation										619,000	$ 343,000	$ 322,000
Unrecognized compensation expense										$ 1,838,000
Shares recognition period										2 years 9 months 3 days
Weighted average remaining contractual term options outstanding										8 years 6 months 21 days
Fair value of RSUs, per share										$ 15.00	$ 6.50	$ 0.00
Fair value of RSUs	$ 1,500,000	$ 1,299,000		$ 340,000						$ 325,000	$ 325,000	$ 340,000
Intrinsic value of restricted share units exercised										$ 821,000	511,000	301,000
2012 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum aggregate number of shares issued										44,758,220
Number of share options granted								0
Number of share options under accelerated vesting to permit immediate exercise							235,000
Incremental cost for acceleration of vesting to permit immediate exercise												162,000
2012 Plan [Member] \| Employee and Executives Share Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation												16,026,000
2012 Plan [Member] \| Non Employee Share Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation												756,000
2014 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation arrangements expiration Period										10 years
Incremental cost for acceleration of vesting to permit immediate exercise											1,532,000
Number of options, Forfeited/Canceled						187,500
Unrecognized compensation expense										$ 122,171,000
Shares recognition period										2 years 11 months 12 days
Weighted average remaining contractual term options outstanding										7 years 4 months 24 days
2014 Plan [Member] \| Class A Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum aggregate number of shares issued								14,031,194
Increase in number of shares reserved for future issuances										1.50%
Number of shares reserved for future issuances, description										Starting from 2017, the number of shares reserved for future issuances under the 2014 Plan will be increased by a number equal to 1.5% of the total number of outstanding shares on the last day of the immediately preceding calendar year, or such lesser number of Class A ordinary shares as determined by the Company’s board of directors, on the first day of each calendar year during the term of the 2014 Plan.
2014 Plan [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, vesting period										4 years
2014 Plan [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, vesting period										2 years
2014 Plan [Member] \| RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, vesting period	4 years	4 years
2014 Plan [Member] \| RSUs [Member] \| Share-based Compensation Award, Tranche Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, vesting period				6 months
Share based payment vesting percentage				50.00%
2014 Plan [Member] \| RSUs [Member] \| Independent Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of share options granted	100,000	200,000		40,001
2014 Plan [Member] \| Employee and Executives Share Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation										$ 42,439,000	28,096,000
2014 Plan [Member] \| Non Employee Share Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation										$ 6,540,000	3,103,000
Momo BVI Share Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options vested										1,812,500
Options expected to vest										1,033,125
Options expected to vest, weighted-average exercise price										$ 0.1077
Options expected to vest, Aggregate intrinsic value										$ 2,000	$ 5,000	$ 18,000
Weighted average fair value per option at grant date, Granted										$ 0.0000	$ 0.0000	$ 0.0544
Total intrinsic value of options exercised										$ 0	$ 0	$ 0
Total fair value of options vested										$ 43,000	$ 185,000	$ 0
Number of options, Forfeited/Canceled										5,000,000
Unrecognized compensation expense										$ 65,000
Shares recognition period										1 year 7 months 2 days
Weighted average remaining contractual term options outstanding										7 years 6 months	8 years 2 months 8 days
Share incentive plan, term of plan			10 years
Momo BVI Share Incentive Plan [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum aggregate number of shares issued			30,000,000
Momo BVI Share Incentive Plan [Member] \| Employee and Executives Share Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, vesting period												4 years
Share-based compensation										$ 59,000	$ 112,000	$ 98,000
Number of options, granted												10,550,000
Exercise price of share options granted, lower range												$ 0.10
Exercise price of share options granted, upper range												$ 0.11

Share-Based Compensation - Summary of Options Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, Outstanding beginning balance	31,606,466
Number of options, granted	5,771,226
Number of options, Exercised	(9,426,874)
Number of options, Forfeited	(981,527)
Number of options, Outstanding ending balance	26,969,291	31,606,466
Number of options, Exercisable	14,743,283
Weighted average exercise price per option, Outstanding beginning balance	$ 0.0641
Weighted average exercise price per option, Granted	0.0002
Weighted average exercise price per option, Exercised	0.0602
Weighted average exercise price per option, Forfeited	0.0132
Weighted average exercise price per option, Outstanding ending balance	0.0536	$ 0.0641
Weighted average exercise price per option, Exercisable	$ 0.0952
Weighted average remaining contractual life, Outstanding beginning balance	7 years 4 months 24 days	7 years 7 months 17 days
Weighted average remaining contractual term options outstanding	7 years 4 months 24 days	7 years 7 months 17 days
Weighted average remaining contractual life, Exercisable	6 years 4 months 20 days
Aggregated intrinsic value, Outstanding beginning balance	$ 288,439
Aggregated intrinsic value, Outstanding ending balance	328,658	$ 288,439
Aggregated intrinsic value, Exercisable	$ 170,053
Momo BVI Share Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, Outstanding beginning balance	8,000,000
Number of options, Forfeited	(5,000,000)
Number of options, Outstanding ending balance	3,000,000	8,000,000
Number of options, Exercisable	1,812,500
Weighted average exercise price per option, Outstanding beginning balance	$ 0.1088
Weighted average exercise price per option, Forfeited	0.1100
Weighted average exercise price per option, Outstanding ending balance	0.1067	$ 0.1088
Weighted average exercise price per option, Exercisable	$ 0.1060
Weighted average remaining contractual life, Outstanding beginning balance	7 years 6 months	8 years 2 months 8 days
Weighted average remaining contractual term options outstanding	7 years 6 months	8 years 2 months 8 days
Weighted average remaining contractual life, Exercisable	7 years 5 months 12 days
Aggregated intrinsic value, Outstanding beginning balance	$ 10
Aggregated intrinsic value, Outstanding ending balance	10	$ 10
Aggregated intrinsic value, Exercisable	$ 7

Share-Based Compensation - Schedule of Assumptions Used to Estimate Fair Value of Stock Options Granted (Detail) - 2014 Plan [Member] - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate of return, minimum	2.47%	1.75%	2.15%
Risk-free interest rate of return, maximum	2.87%	2.70%	2.19%
Contractual term	10 years	10 years	10 years
Volatility, minimum	50.70%	52.50%	55.30%
Volatility, maximum	54.00%	55.30%	55.70%
Dividend yield	0.00%	0.00%	0.00%
Exercise price	$ 0.0002	$ 0.0002	$ 0.0002

Share-Based Compensation - Summary of Non-Vested Restricted Share Activity (Detail) - Non-Vested Restricted Shares [Member] - shares		12 Months Ended
	May 15, 2014	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares, Outstanding beginning balance		28,625,378	57,250,756
Number of shares, Granted		0	0
Number of shares, Modification	19,736,705		0
Number of shares, Forfeited		0
Number of shares, Vested		(28,625,378)	(28,625,378)
Number of shares, Outstanding ending balance	45,937,500		28,625,378

Share-Based Compensation - Summary of Restricted Share Units Granted (Detail) - RSUs [Member]	12 Months Ended
	Dec. 31, 2017 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares, Outstanding beginning balance	150,000
Granted	100,000
Forfeited	0
Vested	(50,000)
Number of shares, Outstanding ending balance	200,000

Net Income Per Share - Calculation of Net Income Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Numerator:
Net income attributable to MomoInc.	$ 318,566	$ 145,250	$ 13,697
Net income attributed to ordinary shareholders for computing net income per ordinary share-basic and diluted	$ 318,566	$ 142,053	$ 12,358
Denominator for computing net income per share-basic:
Weighted average ordinary shares outstanding used in computing net income per ordinary share-basic	394,549,323	377,335,923	342,646,282
Denominator for computing net income per share-diluted:
Weighted average shares outstanding used in computing net income per ordinary share-diluted	415,265,078	407,041,165	401,396,548
Net income per ordinary share attributable to Momo Inc. - basic	$ 0.81	$ 0.38	$ 0.04
Net income per ordinary share attributable to Momo Inc. - diluted	$ 0.77	$ 0.36	$ 0.03
Non-Vested Restricted Shares [Member]
Numerator:
Undistributed earnings		$ (3,197)	$ (1,339)
Denominator for computing net income per share-basic:
Weighted average ordinary shares outstanding used in computing net income per ordinary share-basic		8,493,244	37,118,622
Denominator for computing net income per share-diluted:
Net income per ordinary share attributable to Momo Inc. - basic		$ 0.38	$ 0.04

Net Income Per Share - Summary of Potential Ordinary Shares Outstanding Excluded from Computation of Diluted Net Loss Per Ordinary Share (Detail) - shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential ordinary shares outstanding excluded from the computation of diluted net loss per ordinary share	768,266	152,500	904,489
RSUs [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential ordinary shares outstanding excluded from the computation of diluted net loss per ordinary share		50,000	15,001

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Lease and Investment Commitments [Line Items]
Lease expiration year	2022
Rental expenses under operating leases	$ 8,744	$ 4,743	$ 3,715
Partnership Interest [Member]
Lease and Investment Commitments [Line Items]
Equity method investments equity contribution obligation	$ 4,611	$ 2,942

Commitments and Contingencies - Schedule of Future Minimum Payments under Non-Cancellable Operating Leases (Detail) $ in Thousands	Dec. 31, 2017 USD ($)
Leases [Abstract]
2018	$ 7,671
2019	4,230
2020	2,990
2021	2,262
Total	$ 17,153

Related Party Balances and Transactions - Schedule of Amount Due from Related Parties-current (Detail) - USD ($)
$ in Thousands

Dec. 31, 2017

Dec. 31, 2016

Amount due from related parties

$ 5,143

$ 88

Hunan Qindao Network Media Technology Co., Ltd. [Member]

Amount due from related parties

^[1]

$ 5,143

Hangzhou Alimama Technology Co., Ltd. [Member]

Amount due from related parties

Guangzhou UC Network Technology Co., Ltd. [Member]

Amount due from related parties

Guangzhou Aijiuyou Informational Technology Co., Ltd. [Member]

Amount due from related parties

$ 81

[1]	The amount of $5,143 as of December 31, 2017 represented the advance payment of revenue sharing of live video service made to Hunan Qindao Network Media Technology Co., Ltd.

Related Party Balances and Transactions - Schedule of Amount Due from Related Parties-current (Parenthetical) (Detail) - USD ($)
$ in Thousands

Dec. 31, 2017

Dec. 31, 2016

Advance payment of revenue

$ 5,143

$ 88

Hunan Qindao Network Media Technology Co., Ltd. [Member]

Advance payment of revenue

^[1]

5,143

Hunan Qindao Network Media Technology Co., Ltd. [Member] | Deferred Revenues Net [Member]

Advance payment of revenue

$ 5,143

[1]	The amount of $5,143 as of December 31, 2017 represented the advance payment of revenue sharing of live video service made to Hunan Qindao Network Media Technology Co., Ltd.

Related Party Balances and Transactions - Schedule of Amount Due to Related Parties-current (Detail) - USD ($)
$ in Thousands

Dec. 31, 2017

Dec. 31, 2016

Amount due to related parties

$ 5,804

$ 8,117

Ordinary Shareholders [Member]

Amount due to related parties

^[1]

5,775

5,862

Hunan Qindao Cultural Spread Ltd. [Member]

Amount due to related parties

1,281

Alibaba Cloud Computing Ltd. [Member]

Amount due to related parties

629

Shanghai Touch Future Network Technology Co., Ltd. [Member]

Amount due to related parties

229

Taobao (China) Software Co., Ltd. [Member]

Amount due to related parties

$ 116

Others [Member]

Amount due to related parties

$ 29

[1]	The amounts of $5,862 and $5,775 as of December 31, 2016 and 2017 primarily included the unpaid repurchase amount by the Group to its ordinary shareholders. Please refer to Note 11 for repurchase of ordinary shares.

Related Party Balances and Transactions - Schedule of Amount Due to Related Parties-current (Parenthetical) (Detail) - USD ($)
$ in Thousands

Dec. 31, 2017

Dec. 31, 2016

Amount due to related parties

$ 5,804

$ 8,117

Ordinary Shareholders [Member]

Amount due to related parties

^[1]

5,775

5,862

Unpaid Repurchase [Member] | Ordinary Shareholders [Member]

Amount due to related parties

$ 5,775

$ 5,862

[1]	The amounts of $5,862 and $5,775 as of December 31, 2016 and 2017 primarily included the unpaid repurchase amount by the Group to its ordinary shareholders. Please refer to Note 11 for repurchase of ordinary shares.

Related Party Balances and Transactions - Schedule of Sales to Related Parties (Detail) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Sales to related parties

$ 3,216

$ 2,442

$ 6,002

Hangzhou Yihong Advertisement Co., Ltd. [Member]

Sales to related parties

^[1]

2,614

Hangzhou Alimama Technology Co., Ltd. [Member]

Sales to related parties

^[1]

342

$ 6,002

Guangzhou Aijiuyou Informational Technology Co., Ltd. [Member]

Sales to related parties

^[2]

184

400

Zhejiang Tmall Technology Co., Ltd. [Member]

Sales to related parties

^[1]

820

Shanghai Xisue Network Technology Co., Ltd. [Member]

Sales to related parties

922

Taobao (China) Software Co., Ltd. [Member]

Sales to related parties

^[1]

249

Others [Member]

Sales to related parties

$ 2

$ 9

[1]	The sales to related parties represented mobile marketing services provided.
[2]	The sales to related parties represented mobile game revenue generated through those game operating companies.

Related Party Balances and Transactions - Schedule of Purchase from Related Parties (Detail) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Purchase from related parties

$ 41,287

$ 7,959

$ 322

Hunan Qindao Network Media Technology Co., Ltd. [Member]

Purchase from related parties

^[1]

20,639

Alibaba Cloud Computing Ltd. [Member]

Purchase from related parties

^[2]

11,060

3,360

$ 322

Hunan Qindao Cultural Spread Ltd. [Member]

Purchase from related parties

^[1]

9,131

3,929

Taobao (China) Software Co., Ltd. [Member]

Purchase from related parties

338

323

Guangzhou Jianyue Information Technology Co., Ltd. [Member]

Purchase from related parties

$ 119

Shanghai Touch Future Network Technology Co., Ltd. [Member]

Purchase from related parties

$ 347

[1]	The purchases from Hunan Qindao Network Media Technology Co., Ltd. and Hunan Qindao Cultural Spread Ltd. represent the revenue sharing with broadcaster agencies of live video service.
[2]	The purchase from Alibaba Cloud Computing Ltd. is mainly related to its cloud computing services.

Segment Information - Components of Revenues (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenue from External Customer [Line Items]
Total revenues	$ 1,318,271	$ 553,098	$ 133,988
Live Video Service [Member]
Revenue from External Customer [Line Items]
Total revenues	1,102,592	376,925	1,231
Value-added Services [Member]
Revenue from External Customer [Line Items]
Total revenues	103,139	67,603	58,462
Mobile Marketing [Member]
Revenue from External Customer [Line Items]
Total revenues	76,178	66,339	38,885
Mobile Games [Member]
Revenue from External Customer [Line Items]
Total revenues	35,619	35,453	31,082
Other Services [Member]
Revenue from External Customer [Line Items]
Total revenues	$ 743	$ 6,778	$ 4,328

Statutory Reserves and Restricted Net Assets - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Regulated Operations [Abstract]
Required minimum percentage of annual appropriations	10.00%
General reserve as a percentage of registered capital up to which after-tax profit shall be transferred	50.00%
Appropriations to statutory reserves	$ 27,430	$ 17,969	$ 553
Capital reserves not available for distribution	136,407	108,977	91,008
Statutory reserves not available for distribution	$ 136,407	$ 108,977	$ 91,008

Subsequent Events - Additional Information (Detail) - Tantan Limited ("Tantan") [Member] - Subsequent Event [Member] $ in Millions	Feb. 23, 2018 USD ($) shares
Subsequent Events [Line Items]
Percentage of acquired equity interest	100.00%
Cash consideration	$ 600.9
Cash consideration paid	$ 229.8
Class A Common Stock [Member]
Subsequent Events [Line Items]
Issuance of ordinary shares \| shares	5,300,000

Segment Information - Additional Information (Detail)	12 Months Ended
Segment Information - Additional Information (Detail)	Dec. 31, 2017 Segment
Segment Reporting [Abstract]
Number of operating segments	1

Employee Benefit Plan - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Retirement Benefits [Abstract]
Provisions for employee benefits	$ 14,127	$ 9,081	$ 6,487