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Document and Entity Information	12 Months Ended
Document and Entity Information	Dec. 31, 2018 shares
Entity Registrant Name	WEIBO Corp
Entity Central Index Key	0001595761
Document Type	20-F
Document Period End Date	Dec. 31, 2018
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Shell Company	false
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY
Class A ordinary shares
Entity Common Stock, Shares Outstanding	123,058,593
Class B ordinary shares
Entity Common Stock, Shares Outstanding	101,778,958
Ordinary Shares
Entity Common Stock, Shares Outstanding	224,837,551

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 1,234,596	$ 1,000,953
Short-term investments	591,269	791,730
Accounts receivable due	369,093	170,100
Prepaid expenses and other current assets	168,821	69,233
Amount due from SINA (Note 9)	105,319	16,356
Total current assets	2,469,098	2,048,372
Property and equipment, net	45,623	33,793
Intangible assets, net	21,103	517
Goodwill	29,346	13,420
Long-term investments	694,586	452,337
Other assets	14,926	13,380
Total assets	3,274,682	2,561,819
Current liabilities (including amounts of the consolidated VIEs without recourse to the primary beneficiaries of $217,602 and $347,770 as of December 31, 2017 and 2018, respectively.)
Accounts payable	123,730	64,043
Accrued and other liabilities	317,437	268,615
Income taxes payable	88,683	70,907
Deferred revenues	99,994	81,311
Total current liabilities	629,844	484,876
Long-term liabilities
Convertible debt	884,123	879,983
Long-term deferred revenues		286
Deferred tax liability	12,577	1,880
Total long-term liabilities	896,700	882,149
Total liabilities	1,526,544	1,367,025
Commitments and contingencies (Note 16)
Shareholders' equity:
Ordinary shares: $0.00025 par value; 2,400,000 and 2,400,000 shares (including 1,800,000 Class A ordinary shares, 200,000 Class B ordinary shares and 400,000 shares to be designated) authorized; 222,706 and 224,838 shares (including 123,059 Class A ordinary shares and 101,779 Class B ordinary shares) issued and outstanding as of December 31, 2017 and 2018, respectively.	57	56
Additional paid-in capital	1,071,836	1,030,048
Accumulated other comprehensive income (loss)	(49,615)	9,534
Retained earnings	723,181	152,949
Total Weibo shareholders' equity	1,745,459	1,192,587
Non-controlling interests	2,679	2,207
Total shareholders' equity	1,748,138	1,194,794
Total liabilities and shareholders' equity	3,274,682	2,561,819
Third parties
Current assets:
Accounts receivable due	190,036	97,572
Alibaba
Current assets:
Accounts receivable due	48,222	42,832
Other related parties
Current assets:
Accounts receivable due	$ 130,835	$ 29,696

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Allowance for doubtful accounts	$ 12,429	$ 8,114
Current liabilities	$ 629,844	$ 484,876
Ordinary shares, par value (in dollars per share)	$ 0.00025	$ 0.00025
Ordinary shares, shares authorized	2,400,000	2,400,000
Ordinary shares, shares issued	224,838	222,706
Ordinary shares, shares outstanding	224,838	222,706
Class A ordinary shares
Ordinary shares, shares authorized	1,800,000	1,800,000
Ordinary shares, shares issued	123,059
Ordinary shares, shares outstanding	123,059
Class B ordinary shares
Ordinary shares, shares authorized	200,000	200,000
Ordinary shares, shares issued	101,779
Ordinary shares, shares outstanding	101,779
Ordinary shares to be designated
Ordinary shares, shares authorized	400,000	400,000
Consolidated VIEs without recourse to the primary beneficiaries
Current liabilities	$ 347,770	$ 217,602
Alibaba
Allowance for doubtful accounts	0	0
Other related parties
Allowance for doubtful accounts	630	0
Third parties
Allowance for doubtful accounts	$ 11,799	$ 8,114

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues:
Revenues	$ 1,718,518	$ 1,150,054	$ 655,800
Costs and Expenses
Cost of revenues	277,648	231,255	171,231
Sales and marketing	527,424	275,537	148,283
Product development	249,873	193,393	154,088
General and administrative	43,755	42,315	41,218
Goodwill and acquired intangibles impairment	10,554
Total costs and expenses	1,109,254	742,500	514,820
Income from operations	609,264	407,554	140,980
Income (loss) from equity method investments	57	1,030	(130)
Realized gain (loss) from investments	(287)	14	534
Fair value changes through earnings on investments, net	40,074
Investment related impairment	(24,074)	(4,747)	(40,161)
Interest and other income, net	43,808	13,260	8,757
Income before income tax expenses	668,842	417,111	109,980
Provision of income taxes	96,222	66,746	4,316
Net income	572,620	350,365	105,664
Less: Net income (loss) attributable to non-controlling interests	797	(2,225)	(2,363)
Net income attributable to Weibo	571,823	352,590	108,027
Other comprehensive income (loss)
Currency translation adjustments (net of tax of nil, nil, and nil for 2016, 2017 and 2018, respectively)	(60,273)	37,822	(18,898)
Available-for-Sale securities
Change in unrealized loss from available-for-sale securities (net of tax of nil, nil, and nil for 2016, 2017, and 2018, respectively)		(995)	(2,557)
Reclassification adjustment for net loss included in net income (net of tax of nil, nil, and nil for 2016, 2017, and 2018, respectively)			4,822
Net change, net of tax		(995)	2,265
Total comprehensive income	512,347	387,192	89,031
Less: Comprehensive income (loss) attributable to non-controlling interests	668	(1,926)	(2,637)
Comprehensive income attributable to Weibo	$ 511,679	$ 389,118	$ 91,668
Shares used in computing net income per share attributable to Weibo:
Basic (in shares)	223,751	220,555	214,745
Diluted (in shares)	232,683	225,363	222,859
Income per share:
Basic (in dollars per share)	$ 2.56	$ 1.60	$ 0.50
Diluted (in dollars per share)	$ 2.52	$ 1.56	$ 0.48
Advertising & Marketing
Revenues:
Revenues	$ 1,499,180	$ 996,745	$ 570,982
Value-added services
Revenues:
Revenues	219,338	153,309	84,818
Alibaba \| Advertising & Marketing
Revenues:
Revenues	117,696	84,688	57,908
SINA and other related parties \| Advertising & Marketing
Revenues:
Revenues	209,348	131,512	84,799
Third parties \| Advertising & Marketing
Revenues:
Revenues	$ 1,172,136	$ 780,545	$ 428,275

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Currency translation adjustments, tax	$ 0	$ 0	$ 0
Change in unrealized loss from available-for-sale securities, tax	0	0	0
Reclassification adjustment for net loss included in net income, tax	$ 0	$ 0	$ 0

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Ordinary Shares	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings (Accumulated Deficit)	Non-controlling Interests	Total
Balance at Dec. 31, 2015	$ 53	$ 938,922	$ (10,635)	$ (307,668)	$ 7,357	$ 628,029
Balance (in shares) at Dec. 31, 2015	212,177
Increase (Decrease) in Shareholders' Equity
Issuance of ordinary shares pursuant to stock plan	$ 2	3,981				3,983
Issuance of ordinary shares pursuant to stock plan (in shares)	5,899
Non-cash stock-based compensation		36,902				36,902
Sale (Purchase) of subsidiaries' shares to (from) non-controlling shareholders, net					(587)	(587)
Net income (loss)				108,027	(2,363)	105,664
Currency translation adjustments			(18,624)		(274)	(18,898)
Net change in other comprehensive loss from available-for-sale securities			2,265			2,265
Balance at Dec. 31, 2016	$ 55	979,805	(26,994)	(199,641)	4,133	757,358
Balance (in shares) at Dec. 31, 2016	218,076
Increase (Decrease) in Shareholders' Equity
Issuance of ordinary shares pursuant to stock plan	$ 1	2,206				2,207
Issuance of ordinary shares pursuant to stock plan (in shares)	4,630
Non-cash stock-based compensation		48,037				48,037
Net income (loss)				352,590	(2,225)	350,365
Currency translation adjustments			37,523		299	37,822
Net change in other comprehensive loss from available-for-sale securities			(995)			(995)
Balance at Dec. 31, 2017	$ 56	1,030,048	9,534	152,949	2,207	$ 1,194,794
Balance (in shares) at Dec. 31, 2017	222,706					222,706
Increase (Decrease) in Shareholders' Equity
Issuance of ordinary shares pursuant to stock plan	$ 1	777				$ 778
Issuance of ordinary shares pursuant to stock plan (in shares)	2,132
Non-cash stock-based compensation		41,011				41,011
Sale (Purchase) of subsidiaries' shares to (from) non-controlling shareholders, net					(196)	(196)
Net income (loss)				571,823	797	572,620
Currency translation adjustments			(60,144)		(129)	(60,273)
Balance at Dec. 31, 2018	$ 57	$ 1,071,836	(49,615)	723,181	$ 2,679	$ 1,748,138
Balance (in shares) at Dec. 31, 2018	224,838					224,838
Increase (Decrease) in Shareholders' Equity
Impact of adoption of new accounting guidance (Note 2) \| Impact of adoption of new revenue guidance				(596)		$ (596)
Impact of adoption of new accounting guidance (Note 2) \| Impact of adoption of new guidance for investments in equity securities			$ 995	$ (995)

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net income	$ 572,620	$ 350,365	$ 105,664
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	19,847	15,328	13,982
Stock-based compensation	41,011	48,037	36,902
Provision for allowance for doubtful accounts	6,226	5,478	7,787
Deferred income taxes	4,438	(1,503)	(4,630)
(Income) Loss from equity method investments	(57)	(1,030)	130
Dividend received from equity method investments	657	267
(Gain) Loss on sale of investments	287	(14)	(328)
Fair value changes through earnings on investment	(40,074)
Investment related impairment	24,074	4,747	40,161
Goodwill and acquired intangibles impairment	10,554
(Gain) Loss on disposal of property and equipment	(120)	(85)	191
Amortization of convertible debt issuance cost	4,140	690
Changes in assets and liabilities, net of acquisition:
Prepaid expenses and other current assets	(49,381)	(28,050)	(19,527)
Other assets	(1,044)	(649)	1,134
Accounts payable	64,277	22,121	3,785
Accrued and other liabilities	55,560	88,474	68,102
Deferred revenues	24,375	31,967	9,492
Income taxes payable	20,968	62,323	5,130
Net cash provided by operating activities	488,007	539,151	236,244
Cash flows from investing activities:
Purchases of short-term investments	(1,792,481)	(1,439,558)	(314,363)
Maturities of short-term investments	1,989,055	696,245	373,805
Investment and prepayment in long-term investments	(419,126)	(54,640)	(155,122)
Proceeds from disposal of/refund of prepayment on long-term investments	85,134	2,458	12,188
Proceeds from disposal of property and equipment	136	107
Purchases of property and equipment	(28,350)	(20,454)	(13,253)
Cash paid for business acquisition, net of cash acquired	(40,000)	(2,298)
Net cash used in investing activities	(254,032)	(815,422)	(96,745)
Cash flows from financing activities:
Proceeds from employee options exercised	781	2,285	4,183
Proceeds from convertible notes, net of debt issuance costs		879,293
Payments to non-controlling shareholders	(196)		(1,148)
Net cash provided by (used in) financing activities	(1,415)	883,578	3,035
Effect of exchange rate changes on cash and cash equivalents	1,083	28,880	(15,208)
Net increase in cash and cash equivalents	233,643	636,187	127,326
Cash and cash equivalents at the beginning of the year	1,000,953	364,766	237,440
Cash and cash equivalents at the end of the year	1,234,596	1,000,953	364,766
Supplemental disclosure of cash flow information
Cash paid for income tax	(70,060)	(8,168)	(3,386)
Supplemental schedule of non-cash investing and financing activities
Property and equipment in accounts payable	5,258	3,667	2,158
Uncollected proceeds from sale of subsidiary's shares to non-controlling shareholders			561
Unpaid consideration for acquisitions	10,000
2022 Notes
Cash flows from financing activities:
Proceeds from convertible notes, net of debt issuance costs	879,300
Supplemental disclosure of cash flow information
Cash paid for interest expenses	(11,719)
Third parties
Changes in assets and liabilities, net of acquisition:
Accounts receivable due	(109,654)	(41,395)	(33,109)
Alibaba
Changes in assets and liabilities, net of acquisition:
Accounts receivable due	(8,028)	(18,539)	29,759
Other related parties
Changes in assets and liabilities, net of acquisition:
Accounts receivable due	(103,982)	410	2,372
SINA
Changes in assets and liabilities, net of acquisition:
Amount due to (from) SINA	(48,687)	209	$ (30,753)
Cash flows from investing activities:
Loan to SINA	(149,460)	(59,534)
Repayment of loan by SINA	101,060	62,252
Cash flows from financing activities:
Loan from SINA		62,000
Repayment of loan from SINA	$ (2,000)	(60,000)
Supplemental disclosure of cash flow information
Cash paid for interest expenses		$ (1,537)

Operations and reorganization

12 Months Ended

Dec. 31, 2018

Operations and reorganization

Operations and reorganization

1. Operations and reorganization

Weibo Corporation (“Weibo” or the “Company”) is a leading social media for people to create, share and discover Chinese-language content. It provides an unprecedented and simple way for people and organizations to publicly express themselves in real time, interact with others on a massive global platform and stay connected with the world. As a microcosm of the Chinese society and a cultural phenomenon in China, Weibo allows people to be heard publicly and exposed to the rich ideas, cultures and experiences of the broader world. Media outlets use Weibo as a source of news and a distribution channel for their headline news. Government agencies and officials use Weibo as an official communication channel for disseminating information timely and gauging public opinion to improve public services. Charities use Weibo to make the world a better place by launching charitable projects, seeking donations and volunteers and leveraging celebrities and organizations on Weibo to amplify their impact to society. Weibo generates its revenues mostly from advertising and marketing services, as well as from value-added services, including VIP membership, live streaming, and game-related services.

Incorporated in the Cayman Islands, Weibo Corporation is a controlled subsidiary of Sina Corporation (the “Parent” or “SINA”). In April 2014, the Company completed an initial public offering (the “IPO”) and received $306.5 million in net proceeds. Immediately prior to the completion of the IPO, all the ordinary shares held by SINA was converted into an equal number of the Class B ordinary shares, all the ordinary shares held by other shareholders was converted into an equal number of the Class A ordinary shares, and all of its outstanding preferred shares were automatically converted into Class A ordinary shares. The call option held by a subsidiary of Alibaba Group was exercised to purchase Class A ordinary shares from SINA and the Company. Each Class A ordinary share is entitled to one vote per share and each Class B ordinary share is entitled to three votes per share. Each Class B ordinary share can be converted into one Class A ordinary share at any time, while Class A ordinary shares cannot be converted into Class B ordinary shares.

Reorganization

The Weibo business was founded by SINA, its parent, in 2009. Prior to the establishment of the Company, the operation of Weibo business was carried out by various subsidiaries and variable interest entities (“VIE”) of SINA (the “Predecessor Operations”). After its establishment, the Company gradually completed the reorganization steps as described below (the “Reorganization”).

Establishment of Weibo Corporation. Weibo Corporation, an exempted company with limited liability, is the holding company for the Weibo business. Weibo HK is a wholly owned subsidiary of Weibo, and Weibo Technology, a wholly foreign-owned enterprise, (“the WFOE”), is a subsidiary of Weibo HK. The Company’s VIEs and VIEs’ subsidiaries are controlled by the WFOE through a series of contractual agreements. Weibo Corporation, its subsidiaries, VIEs and VIEs’ subsidiaries together are referred to as “the Group.”

The following sets forth the Company’s major subsidiaries, major VIE and major VIE’s subsidiary:


			Percentage of
			Direct/
			Indirect
	Date of	Place of	Economic
Company	Incorporation	Incorporation	Interest
Major Subsidiaries
Weibo Hong Kong Limited (“Weibo HK”)	July 19, 2010	Hong Kong	100	%

Weibo Internet Technology (China) Co., Ltd. (“Weibo Technology” or "the WFOE”)	October 11, 2010	PRC	100	%

Major VIE and major VIE's subsidiary
Beijing Weimeng Technology Co., Ltd (“Weimeng")	August 9, 2010	PRC	100	%

Beijing Weibo Interactive Internet Technology Co., Ltd. (‘‘Weibo Interactive’’)	Acquired in May 2013	PRC	100	%

Intellectual Property License Agreement. The intellectual property license agreement was entered into by and between SINA and the Company in April 2013. Under this agreement, SINA granted the Company and its subsidiaries a perpetual, worldwide, royalty-free, fully paid-up, non-sublicensable, non-transferable, limited, exclusive license of certain trademarks and a non-exclusive license of certain other intellectual property owned by SINA to make, sell, offer to sell and distribute products, services and applications on a microblogging and social networking platform. The Company granted SINA and its affiliates a non-exclusive, perpetual, worldwide, non-sublicensable, non-transferable limited license of certain of the Company’s intellectual property to use, reproduce, modify, prepare derivative works of, perform, display or otherwise exploit such intellectual property. This agreement commenced on April 29, 2013 and will continue to be in effect unless terminated by SINA should the Company breach the terms as provided in the agreement.

Basis of Presentation for the Reorganization. Since the Group and the Predecessor Operations are under common control, the accompanying consolidated financial statements include the assets, liabilities, revenue, expenses and cash flows that were directly attributable to the Predecessor Operations for all periods presented. The assets and liabilities have been stated at historical carrying amounts.

Accounts receivable amounts directly related to Weibo but for which SINA will receive payments and remit payments to the Group, as well as accounts receivable directly from SINA, are included in the amount due from SINA. Liabilities directly related to Weibo but for which SINA will make payments and receive reimbursements from the Group, as well as liabilities directly to SINA, are included in the amount due to SINA. Loans from SINA are presented under cash flow from financing activities, whereas loans to SINA are presented under investing activities in the consolidated statements of cash flows. Cash payment for billings from SINA for costs and expenses allocated is presented under operating activities in the consolidated statements of cash flows. The Group’s statements of comprehensive income consists all the related costs and expenses of the Weibo business, including allocation to the cost of revenues, sales and marketing expenses, product development expenses, and general and administrative expenses, which are incurred by SINA but related to the Weibo business. These allocations were based on proportional cost allocation by considering proportion of the revenues, infrastructure usage metrics and labor usage metrics, among other things, attributable to the Group and are made on a basis considered reasonable by management.

Total cost and expenses allocated from SINA were as follows:


	Year Ended December 31,
	2016		2017		2018
	(In thousands)
Cost of revenues	$	11,022	$	13,699	$	16,824
Sales and marketing		1,271		9,732		11,558
Product development		9,094		11,312		11,688
General and administrative		4,316		6,393		7,264
	$	25,703	$	41,136	$	47,334

However, while the expenses allocated to the Group for these items are not necessarily indicative of the expenses that would have been incurred if the Group had been a separate and independent entity, the Company does not believe that there is any significant difference between the nature and amount of these allocated expenses and the expenses that would have been incurred if the Group had been a separate and stand-alone entity.

Consolidation

The consolidated financial statements include the accounts of the Company, its wholly-owned subsidiaries, VIEs, of which the Company is the primary beneficiary, and VIEs' subsidiaries. All significant intercompany balances and transactions have been eliminated.

To comply with PRC laws and regulations, the Group provides a substantial amount of its services in China via the VIEs, which holds critical operating licenses that enable the Group to do business in China. Most of the Group’s revenues, costs and net income in China were generated directly or indirectly through the VIEs or the Predecessor Operations. The Company, through its subsidiary, has signed various agreements with the VIEs to allow the transfer of economic benefits from the VIEs to the Company. The Group has determined that it is the primary beneficiary of the VIEs through Weibo Technology’s contractual arrangements with the VIEs. Accordingly, the Company has consolidated the VIEs’ results of operations and assets and liabilities in the Group’s financial statements pursuant to the United States Generally Accepted Accounting Principles (“US GAAP”) for all the periods presented.

Shareholders of the VIEs are certain nominee shareholders from the Company or SINA. The capital for their investments in the VIEs is funded by the Company and recorded as interest-free loans to these individuals. These loans were eliminated with the capital of the VIEs during consolidation. Each shareholder of the VIEs has agreed to transfer their equity interest in the VIEs to Weibo Technology when permitted by PRC laws and regulations or to designees of the Company at any time for the amount of loans outstanding. All voting rights of the VIEs, including without limitation the right to appoint all directors of the VIEs, has been assigned to Weibo Technology. Weibo Technology has also entered into exclusive technical service agreements with the VIEs under which Weibo Technology provides technical and other services to the VIEs in exchange for substantially all net income of the VIEs. In addition, the shareholders of the VIEs have pledged their shares in the VIEs as collateral for the non-payment of loans or for the technical and other services fees due to Weibo Technology. As of December 31, 2017 and 2018, the total amount of interest-free loans to the VIEs’ shareholders was $86.9 million and $82.1 million, respectively. The aggregate accumulated loss of the VIEs and VIEs’ subsidiaries was $33.3 million as of December 31, 2017 and the VIEs and VIEs’ subsidiaries achieved an aggregate accumulated income of $23.2 million as of December 31, 2018, which were included in the Group’s consolidated financial statements.

The following table sets forth the assets, liabilities, results of operations and cash flows of the VIEs and VIEs’ subsidiaries taken as a whole, which are included in the Group’s consolidated balance sheets and statements of comprehensive income:


	As of December 31,
	2017		2018
	(In thousands)
Cash, cash equivalents and short-term Investments	$	40,458	$	55,506
Accounts receivable		166,212		366,128
Property and equipment, net		146		449
Intangible assets		517		21,103
Goodwill		13,123		29,346
Prepayment for long-term investments		4,967		1,454
Long-term investments		74,935		275,819
Deferred tax assets		4,772		5,778
Amount due from SINA		4,677		31,787
Others		28,850		121,220
Total assets	$	338,657	$	908,590

Accounts payable	$	32,444	$	79,881
Accrued and other liabilities		114,239		181,188
Deferred revenues		54,651		65,531
Income tax payable		16,268		21,170
Amount due to the subsidiaries of the Group		57,639		440,563
Deferred tax liability		129		11,875
Total liabilities	$	275,370	$	800,208


	Year Ended December 31,
	2016		2017		2018
	(In thousands)
Net revenues	$	530,598	$	906,129	$	1,416,367
Net income (loss)	$	(21,758)	$	21,252	$	56,466


	Year Ended December 31,
	2016		2017		2018
	(In thousands)
Net cash provided by (used in) operating activities	$	(42,556)	$	(66,972)	$	46,738
Net cash used in investing activities	$	(28,577)	$	(34,720)	$	(331,243)
Net cash provided by (used in) financing activities	$	(1,148)	$	76,232	$	292,151
Net increase (decrease) in cash and cash equivalents	$	(72,281)	$	(25,460)	$	7,646

Under the contractual arrangements with the VIEs, the Company has the power to direct activities of the VIEs through Weibo Technology and can have assets transferred freely out of the VIEs without restrictions. Therefore, the Company considers that there is no asset of the VIEs that can only be used to settle obligations of the VIEs and VIEs’ subsidiaries, except for the registered capital and non-distributable reserve funds of the VIEs and VIEs’ subsidiaries, amounting to $137.3 million and $144.1 million as of December 31, 2017 and 2018, respectively. Since the VIEs are incorporated as limited liability companies under the PRC Company Law, creditors of the VIEs do not have recourse to the general credit of the Company. There is currently no contractual arrangement that would require the Company to provide additional financial support to the VIEs. As the Company is conducting certain businesses mainly through the VIEs, the Company may provide such support on a discretionary basis in the future, which could expose the Company to a loss. The total amount of costs and expenses allocated from SINA to the VIEs was $12.3 million, $21.4 million and $25.6 million for the years ended December 31, 2016, 2017 and 2018, respectively.

Unrecognized revenue-producing assets held by the VIEs include the Internet Content Provision License, the Online Culture Operating Permit, and the domain names of Weibo.com, Weibo.cn and Weibo.com.cn. Recognized revenue-producing assets held by the VIEs include live streaming platform technology, supplier-relationship contracts, and trademark and domain names, which were acquired through the Yizhibo acquisition. Unrecognized revenue-producing assets, including customer lists relating to advertising and marketing services, VIP membership, and game-related services, as well as trademarks, are also held by Weibo Technology.

The following is a summary of the VIEs agreements:

Loan Agreements. The Company’s wholly owned subsidiary Weibo Technology has granted interest-free loans to each shareholder of the VIEs with the sole purpose of providing funds necessary for capital injection into the VIEs. The terms of the loans are for 10 years, and Weibo Technology has the right to, at its own discretion, shorten or extend the terms of the loans, if necessary. These loans were eliminated with the capital of the VIEs during consolidation.

Share Transfer Agreements. Each shareholder of the VIEs has granted Weibo Technology an option to purchase his shares in the VIEs at a purchase price equal to the amount of the capital injection. Weibo Technology may exercise such option at any time until it has acquired all of the shares of the VIEs, subject to applicable PRC laws. The option will be effective until the earlier of (i) the shareholders of the VIEs and Weibo Technology have fully performed their obligations under this agreement, and (ii) the respective shareholders of the VIEs and Weibo Technology agree to terminate the share transfer agreement in writing.

Loan Repayment Agreements. Each shareholder of the VIEs has agreed with Weibo Technology that the interest-free loans under the loan agreements shall only be repaid through share transfer. Once the share transfers are completed, the purchase price for the share transfer will be set off against the loan repayment. These agreements will be effective until the earlier of (i) Weibo Technology and the shareholders of the VIEs have fully performed their obligations under these agreements, and (ii) Weibo Technology and the shareholders of the VIEs agree in writing to terminate these agreements.

Agreements on Authorization to Exercise Shareholder’s Voting Power. Each shareholder of the VIEs has authorized Weibo Technology to exercise all his voting power as a shareholder of the VIEs on all matters requiring shareholders’ approval under PRC laws and regulations and the articles of association of the VIEs, including without limitation to the appointment of directors, transfer, mortgage or dispose of the VIEs’ assets, transfer of any equity interest in the VIEs, and merger, split, dissolution and liquidation of the VIEs. The authorizations are irrevocable and will not expire until the VIEs dissolve.

Share Pledge Agreements. Each shareholder of the VIEs has pledged all of his shares in the VIEs and all other rights relevant to the share rights to Weibo Technology, as a collateral security for his obligations to pay off all debts to Weibo Technology, under the loan agreement and for the payment obligations of the VIEs under the trademark license agreement and the technical services agreement. In the event of default of any payment obligations, Weibo Technology will be entitled to certain rights, including transferring the pledged shares to itself and disposing the pledged shares through sale or auction. During the term of each agreement, Weibo Technology is entitled to receive all dividends and distributions paid on the pledged shares. The pledges will be effective until the earlier of (i) the third anniversary of the due date of the last guaranteed debt, (ii) the VIEs and the shareholders of the VIEs have fully performed their obligations under the above-referred agreements, and (iii) Weibo Technology unilaterally consents to terminate the respective share pledge agreement. As of the date of this annual report, the registration of such equity pledges is still in the process.

Exclusive Technical Services Agreement, Exclusive Sales Agency Agreement and Trademark License Agreement. The VIEs have entered into an exclusive technical services agreement, an exclusive sales agency agreement and a trademark license agreement with Weibo Technology. Under the exclusive technical services agreement, Weibo Technology is engaged to provide technical services for the VIEs’ online advertising and other related businesses. Under the exclusive sales agency agreement, the VIEs have granted Weibo Technology the exclusive right to distribute, sell and provide agency services for all the products and services provided by the VIEs. The term of the technical service agreement and the sales agency agreement will not expire until the VIEs dissolve.

Due to its control over the VIEs, Weibo Technology has the right to determine the service fee to be charged to the VIEs under these agreements. By considering, among other things, the technical complexity of the service, the actual cost that may be incurred for providing such service, the operations of the VIEs, applicable tax rates, planned capital expenditure and business strategies, Weibo Technology charged an amount of $335.6 million, $618.1 million and $842.6 million in service fees from the VIEs under these agreements for the years ended December 31, 2016, 2017 and 2018, respectively, which was determined based on the actual cost incurred for providing such service and the cash position and operation of the VIEs.

Under the trademark license agreement, Weibo Technology has granted the VIEs trademark licenses to use its trademarks for specific areas, and the VIEs are obligated to pay license fees to Weibo Technology. The term of the agreement is for one year and is automatically renewed provided that there is no objection from Weibo Technology.

The Company believes that the contractual arrangements among its subsidiary, VIEs and VIEs’ shareholders are in compliance with the current PRC laws and legally enforceable. However, uncertainties in the interpretation and enforcement of the PRC laws, regulations and policies could limit the Company’s ability to enforce these contractual arrangements. As a result, the Company may be unable to consolidate the VIEs and VIEs’ subsidiaries in the consolidated financial statements. The Company’s ability to control the VIEs also depends on the authorization by the shareholders of the VIEs to exercise voting rights on all matters requiring shareholder approval in the VIEs. The Company believes that the agreements on authorization to exercise shareholder’s voting power are legally enforceable. In addition, if the legal structure and contractual arrangements with the VIEs were found to be in violation of any future PRC laws and regulations, the Company may be subject to fines or other actions. The Company believes the possibility that it will no longer be able to control and consolidate the VIEs as a result of the aforementioned risks and uncertainties are remote.

Significant Accounting Policies

12 Months Ended

Dec. 31, 2018

Significant Accounting Policies

Significant Accounting Policies

2. Significant Accounting Policies

Basis of presentation

The preparation of the Group’s consolidated financial statements is in conformity with US GAAP. The consolidated financial statements include the accounts of Weibo, its wholly owned subsidiaries, VIEs, and VIEs’ subsidiaries. All significant intercompany balances and transactions have been eliminated.

Use of estimates

Conformity with US GAAP requires the use of estimates and judgments that affect the reported amounts in the consolidated financial statements and accompanying notes. These estimates form the basis for judgments the management makes about the carrying values of the assets and liabilities, which are not readily apparent from other sources. GAAP requires making estimates and judgments in several areas, including, but not limited to, the basis of consolidation, revenue recognition, fair value accounting, income taxes, goodwill and other long-lived assets, allowances for doubtful accounts, stock-based compensation, the estimated useful lives of assets and convertible debt. The management bases the estimates and judgments on historical information and on various other assumptions that management believes are reasonable under the circumstances. Actual results could differ materially from such estimates.

Revenue recognition

In May 2014, the Financial Accounting Standards Board ("FASB") issued, ASU 2014-09, “Revenue from Contracts with Customers (Topic 606).” The Group adopted the new revenue guidance since January 1, 2018 using the modified retrospective method. Results for reporting periods beginning on or after January 1, 2018 are presented under ASC 606, while prior period amounts are not adjusted and continue to be reported in accordance with the Group’s historic accounting method under ASC 605. The main impacts are a) the presentation of value added tax recognized in revenue from "gross" to "net", which results in equal decrease of revenues and cost of revenues, and b) the recognition of revenues and expenses at fair value for advertising barter transactions, which mainly results in the increase of revenue and advertising expenses. The cumulative-effect adjustment on the retained earnings as of January 1, 2018 related to the initial application of the new revenue standard was a decrease of $0.6 million, which resulted from advertising barter transactions.

Impact of Adoption

The cumulative-effect adjustment on the retained earnings as of January 1, 2018 related to the initial application of the new revenue standard was $0.6 million, which resulted from advertising barter transactions. The adoption resulted in an increase of $2.1 million in deferred revenue and an increase of $0.6 million in other current assets as of December 31, 2018.

The table below summarized the impact of adoption of the new revenue standard on the Group’s consolidated statement of comprehensive income for the year ended December 31, 2018.


	Year ended December 31, 2018
		Adjustments
			Barter
	ASC 605	VAT	Transaction	ASC 606
	($ In thousands)
Total revenues	1,703,644	(95,470)	110,344	1,718,518
Costs and expenses
Cost of revenues	373,118	(95,470)	—	277,648
Sales and marketing	418,004	—	109,420	527,424
Income from operations	608,340	—	924	609,264

Under ASC 606, revenues are recognized when control of the promised goods or services is transferred to customers, in an amount that reflects the consideration the Group expects to be entitled to in exchange for those goods or services. The Group identifies its contracts with customers and all performance obligations within those contracts. The Group then determines the transaction price and allocates the transaction price to the performance obligations within the Group's contracts with customers, recognizing revenue when, or as, the Group satisfies its performance obligations.

The Group does not believe that significant management judgments are involved in revenue recognition, but the amount and timing of the Group’s revenues could be different for any period if management made different judgments. Certain customers may receive sales rebates, which are accounted for as variable consideration. The Group estimates annual expected revenue volume of each individual agent with reference to their historical results. The Group recognizes revenue for the amount of fees it receives from its advertisers, after deducting estimated sales rebates and net of value-added tax (“VAT”) under ASC 606. The Group believes that there will not be significant changes to its estimates of variable consideration.

Revenue disaggregated by revenue source for the years ended December 31, 2016, 2017 and 2018 consists of the following:


	Year Ended December 31,
	2016		2017		2018
	(In thousands)
Advertising and marketing revenues	$	570,982	$	996,745	$	1,499,180
Value-added services revenues		84,818		153,309		219,338
Total revenues	$	655,800	$	1,150,054	$	1,718,518

The Group enters into contracts with its customers, which may give rise to contract assets (unbilled revenue) or contract liabilities (deferred revenue). The payment terms and conditions within the Group’s contracts vary by the type and location of its customers and products or services purchased, the substantial majority of which are due in less than one year. No material impact on the contract assets arose from the new guidance of revenue recognition. Deferred revenue related to unsatisfied performance obligations at the end of the period mainly consists of the unamortized balance of customer advance of advertising and marketing services. The deferred revenues are amortized on a straight-line basis through the service period. Due to the generally short-term duration of the contracts, the majority of the performance obligations are satisfied in the following reporting period. The amount of revenue recognized that was included in the deferred revenue balance at the beginning of the period was $67.2 million for the year ended December 31, 2018.

Practical Expedients and Exemptions

The Group generally expenses sales commissions when incurred because the amortization period is generally one year or less. These costs are recorded within sales and marketing expenses.

Advertising and marketing revenues

Advertising and marketing revenues are derived principally from online advertising, including social display ads and promoted marketing. Social display ad arrangements allow customers to place advertisements on particular areas of the Group’s platform or website in particular formats and over particular periods of time, which is typically no more than three months. The Group enters into cost per mille (“CPM”), or cost per thousand impressions, advertising arrangements with the customers, under which the Group recognizes revenues based on the number of times that the advertisement has been displayed. The Group also enters into cost per day (“CPD”) advertising arrangements with customers, under which the Group recognizes revenues ratably over the contract periods. Promoted marketing arrangements are primarily priced based on CPM. Under the CPM model, customers are obligated to pay when the advertisement is displayed.

The Group’s majority revenue transactions are based on standard business terms and conditions, which are recognized net of agency rebates. The agency rebates are accounted for as variable consideration and are estimated during interim periods based on estimated annual revenue volume of each individual agent with reference to their historical results, which involves accounting judgment. The Group believes its estimation approach in variable consideration results in revenue recognition in a manner consistent with the underlying economics of the transaction.

The Group’s contracts with customers may include multiple performance obligations, which primarily consist of combination of service to allow customers to place advertisements on different areas of its platform or website. For such arrangements, advertising arrangements involving multiple deliverables are broken down into single-element arrangements based on their stand-alone selling price for revenue recognition purposes. The estimation of stand-alone selling price involves significant judgment, especially for the deliverables that have not been sold separately. For those deliverables, the Group determines best estimate of the stand-alone selling price by taking into consideration of the pricing of advertising areas of the Group’s platform or website with similar popularities and advertisements with similar formats and quoted prices from competitors and other market conditions. The Group believes the estimation approach in stand-alone selling price and allocation of the transaction price on a relative stand-alone selling price to each performance obligation results in revenue recognition in a manner consistent with the underlying economics of the transaction and the allocation principle included in ASC 606. Revenues recognized with reference to best estimation of selling price were immaterial for all periods presented. Most of such contracts have all performance obligations completed within one year. Changes in judgments on these assumptions and estimates could materially impact the timing or amount of revenue recognition.

Revenues from barter transactions are recognized during the period in which the advertisements are displayed on the Group’s properties. Barter transactions in which physical goods or services are received in exchange for advertising services are recorded based on the fair values of the goods or services received.

Value-added services revenues

The Group generates value-added services revenues principally from fee-based services, mainly including VIP membership, live streaming, and game-related services. Revenues from these services are recognized when control of the promised services is transferred to customers, in an amount that reflects the consideration the Group expects to be entitled to in exchange for those services.

VIP membership. VIP membership is a service package consisting of one performance obligation of providing user certification and preferential benefits, such as daily priority listings and higher quota for following user accounts. Prepaid VIP membership fees are recorded as deferred revenue and recognized as revenue ratably over the contract period of the membership service.

Live streaming. Live streaming generates revenue from sales of virtual items on the Yizhibo platform. Users can access the platform and view the live streaming content and interact with the broadcasters for free.

The Group designs, creates and offers various virtual items for sales to users with pre-determined selling price. Each virtual item is considered as a distinctive performance obligation. Sales proceeds are recorded as deferred revenue and recognized as revenue based on the consumption of the virtual items. Users can purchase and present virtual items to broadcasters to show support for their favorite ones. Under the arrangements with broadcasters or broadcaster agencies, the Group shares with them a portion of the revenues derived from the consumption of virtual items. Revenues derived from the sale of virtual items 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 streaming services. The portion paid to broadcasters and/or broadcaster agencies is recognized as cost of revenues. The Group does not have further obligations to the user after the virtual items are consumed.

Game-related services. Game-related service revenues are mostly generated from the purchase of virtual items by game players through the Group’s platform. Each virtual item is considered as a distinctive performance obligation. The Group collects payments from the game players in connection with the sale of virtual currency, which can be used to purchase virtual items in online games. Revenue is recorded on a gross basis for games that the Group is acting as the principal in fulfilling all obligations related to the games and revenue is recorded net of predetermined revenue sharing with the game developers for games in which the Group is not acting as the principal in fulfilling all obligations. Sales of virtual currencies are recognized as revenues over the estimated consumption period of in-game virtual items, which is typically from a few days to one month. Virtual currency sold for game-related services in excess of recognized revenues is recorded as deferred revenues.

Cost of revenues

Cost of revenues consists mainly of costs associated with the maintenance of platform, which primarily include bandwidth and other infrastructure costs, labor cost and turnover taxes levied on the revenues, part of which were allocated from SINA (see Note 1 Reorganization). The Group presents taxes assessed by a governmental authority that are both imposed on and concurrent with a specific revenue-producing transaction on a gross basis in the financial statements. The Group is subject to 6.7% Value-Added Tax ("VAT") and surcharges for its revenues and an additional 3% cultural business construction fees for its advertising and marketing revenues. Pursuant to the adoption of ASC 606 effectively beginning January 1, 2018, the new guidance of revenue recognition requires the presentation of Value-Added Tax (“VAT”) recognized in revenue from "gross" to "net", which results in equal decrease of revenues and cost of revenues. The total amount of such taxes on its advertising and marketing revenues for the years ended December 31, 2016, 2017 and 2018 were $49.9 million, $90.6 million and $52.9 million, respectively, with VAT not included in the cost of revenues for the year ended December 31, 2018.

Sales and Marketing Expenses

Sales and marketing expenses consist mainly of online and offline advertising and promotional expenses, salary, benefits and commission expenses, and facility expenses. Advertising and promotional expenses generally represent the expenses of promotions of corporate image and product marketing. The Group expenses all advertising and promotional expenses as incurred and classifies these expenses under sales and marketing expenses. Pursuant to the adoption of ASC 606 effectively beginning January 1, 2018, the new guidance of revenue recognition requires the recognition of revenues and expenses at fair value for advertising barter transactions, which mainly results in the increase of revenue and advertising expenses. For the years ended December 31, 2016, 2017 and 2018, the advertising and promotional expenses were $92.2 million, $200.6 million and $428.8 million, respectively.

Product development expenses

Product development expenses consist mainly of payroll-related expenses and infrastructure costs incurred for enhancement to and maintenance of the Group’s platform, as well as costs associated with new product development and product enhancements, part of which were allocated from SINA (see Note 1 Reorganization ). The Group expenses all costs incurred for the planning and post implementation phases of development and costs associated with repair or maintenance of the existing site or the development of platform content. Since inception, the amount of costs qualifying for capitalization has been immaterial and, as a result, all product development costs have been expensed as incurred.

Stock-based compensation

All stock-based awards to employees and directors, such as stock options and restricted share units (“RSUs”), are measured at the grant date based on the fair value of the awards. Stock-based compensation, net of forfeitures, is recognized as expenses on a straight-line basis over the requisite service period, which is the vesting period.

The Group uses the Black-Scholes option pricing model to estimate the fair value of stock options. The determination of estimated fair value of stock-based payment awards on the grant date using an option pricing model is affected by the fair value of the Company’s ordinary shares as well as assumptions regarding a number of complex and subjective variables. These variables include the expected value volatility of the Company over the expected term of the awards, actual and projected employee stock option exercise behaviors, a risk-free interest rate and expected dividends, if any. Options granted generally vest over four years.

The Group recognizes the estimated compensation cost of restricted share units based on the fair value of its ordinary shares on the date of the grant. The Group recognizes the compensation cost, net of estimated forfeitures, over a vesting term of generally four years for service-based restricted share units. The Group also recognizes the compensation cost of performance-based restricted share units, net of estimated forfeitures, if it is probable that the performance condition will be achieved at the end of each reporting period.

Forfeitures are estimated at the time of grant and revised in subsequent periods if actual forfeitures differ from those estimates. The Group uses historical data to estimate pre-vesting option and records stock-based compensation expense only for those awards that are expected to vest. See Note 6 Stock-based Compensation for further discussion on stock-based compensation.

Taxation

Income taxes

Income taxes are accounted for using the asset and liability approach. Under this approach, income tax expense is recognized for the amount of taxes payable or refundable for the current year. In addition, deferred tax assets and liabilities are recognized for expected future tax consequences of temporary differences between the financial reporting and tax bases of assets and liabilities, and for operating losses and tax credit carry forwards. The Group records a valuation allowance to reduce deferred tax assets to an amount for which realization is more likely than not.

Uncertain tax positions. To assess uncertain tax positions, the Group applies a more likely than not threshold and a two-step approach for the tax position measurement and financial statement recognition. Under the two-step approach, the first step is to evaluate the tax position for recognition by determining if the weight of available evidence indicates that it is more likely than not that the position will be sustained, including resolution of related appeals or litigation processes, if any. The second step is to measure the tax benefit as the largest amount that is more than 50% likely of being realized upon settlement.

Operating leases

The Group leases office space under operating lease agreements with initial lease terms up to five and a half years. Rental expense is recognized from the date of initial possession of the leased property on a straight-line basis over the term of the lease, part of which was allocated from SINA (see Note 1 Reorganization). Certain lease agreements contain rent holidays, which are recognized on a straight-line basis over the lease term. Lease renewal periods are considered on a lease-by-lease basis and are generally not included in the initial lease terms. The allocated rental expenses from SINA for the years ended December 31, 2016, 2017 and 2018, were $3.9 million, $4.5 million and $4.9 million, respectively.

Cash equivalents

The Group considers all highly liquid investments with original maturities of three months or less as cash equivalents. Cash equivalents are comprised of investments in time deposits that mature within three months stated at cost plus accrued interest.

Accounts receivable and allowances for doubtful accounts

Accounts receivable are recorded and carried at the original invoiced amount less an allowance for any potential uncollectible amounts. The Group maintains an allowance for doubtful accounts which reflects its best estimate of amounts that will not be collected. The Group determines the allowance for doubtful accounts based on a historical, rolling average, bad debt rate in the prior period and other factors, such as credit-worthiness of the customers and the age of the receivable balances. The Group also provides specific provisions for bad debts when facts and circumstances indicate that the receivable is unlikely to be collected. If the financial condition of the Group’s customers were to deteriorate, resulting in an impairment of their ability to make payments, more bad debt allowances may be required.

Fair value measurements

Financial instruments

All financial assets and liabilities are recognized or disclosed at fair value in the consolidated financial statements on a recurring basis. Accounting guidance defines fair value as 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.

The Group measures the equity method investments at fair value on a non-recurring basis only if an impairment charge were to be recognized. For those investments without readily determinable fair value, the Group measures them at fair value when observable price changes are identified or impairment charge was recognized. The fair values of the Group’s privately held investments as disclosed are determined based on the discounted cash flow model using the discount curve of market interest rates or based on the similar transaction price in the market directly. The fair values of the Group’s long-term investments in the equity securities of publicly listed companies are measured using quoted market prices. The Group’s non-financial assets, such as intangible assets, goodwill and fixed assets, would be measured at fair value only if they were determined to be impaired.

Accounting guidance establishes 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. A financial instrument’s categorization within the fair value hierarchy is based upon the lowest level of input that is significant to the fair value measurement. Accounting guidance establishes three levels of inputs that may be used to measure fair value:

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

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 asset or liability such as quoted prices for similar assets or liabilities in active markets; quoted prices for identical asset 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 applies to asset 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.

The carrying amount of cash and cash equivalents, short-term investments, accounts receivable due from third parties, accounts receivable due from Alibaba, accounts receivable due from other related parties, amount due from/to SINA, accounts payable, accrued and other liabilities approximates fair value because of their short-term nature. See Note 14 Fair Value Measurement for additional information.

Long-term investments

Long-term investments are comprised of investments in publicly traded companies, privately held companies, and limited partnerships. The Group uses the equity method to account for ordinary-share-equivalent equity investments over which it has significant influence but does not own a majority equity interest or otherwise control.

Adoption of ASU 2016-01 and Its Implication

Before the adoption of ASU 2016-01 in 2018, the Group used cost method to account for equity investments over which the Group does not have significant influence, or the investments in which the Group holds equity shares that are not common shares/in-substance common share without readily determinable fair value. For marketable equity securities, the Group reported them at fair value and accounted for them as available-for-sale (“AFS”) securities under long-term investments.

After adopting ASU 2016-01 on January 1, 2018, the Group measures investments in equity securities, other than equity method investments, at fair value through earnings. For those investments without readily determinable fair values, the Group elects to record these investments at cost, less impairment, and plus or minus subsequent adjustments for observable price changes. Under this measurement alternative, changes in the carrying value of the investments will be recognized in consolidated statement of comprehensive income, whenever there are observable price changes in orderly transactions for the identical or similar investment of the same issuer.

The marketable equity securities were reclassified as investments with readily determinable fair values under the ASU 2016-01. There will no longer be an available-for-sale classification for equity securities. The cumulative effects of applying the guidance to the Group’s consolidated balance sheets were the reclassification of unrealized loss of $1.0 million from accumulated other comprehensive income to retained earnings as of January 1, 2018. (see Note 4 for further information)

Pursuant to ASC 321, for equity investments measured at fair value with changes in fair value recorded in earnings, the Group does not assess whether those securities are impaired. For those equity investments that the Group elects to use the measurement alternative, the Group makes a qualitative assessment of whether the investment is impaired at each reporting date. If a qualitative assessment indicates that the investment is impaired, the entity has to estimate the investment’s fair value in accordance with the principles of ASC 820. If the fair value is less than the investment’s carrying value, the entity has to recognize an impairment loss in net income equal to the difference between the carrying value and fair value. Prior to 2018, these securities were classified as available-for-sale securities and measured and recorded at fair value with unrealized changes in fair value recorded through other comprehensive income.

Investments in entities which the Group can exercise significant influence and holds an investment in voting common shares or in-substance common shares (or both) of the investee but does not own a majority equity interest or control are accounted for using the equity method of accounting in accordance with ASC topic 323 (“ASC 323”), Investment --- Equity Method and Joint Ventures. Under the equity method, the Group initially records its investments at cost and the difference between the cost of the equity investee and the fair value of the underlying equity in the net assets of the equity investee is recognized as equity method goodwill, which is included in the equity method investment on the consolidated balance sheets. The Group subsequently adjusts the carrying amount of the investments to recognize the Group’s proportionate share of each equity investee’s net income or loss into earnings after the date of investment. The Group evaluates the equity method investments for impairment under ASC 323. An impairment loss on the equity method investments is recognized in earnings when the decline in value is determined to be other-than-temporary.

The Group recorded an impairment charge of $36.4 million, $4.7 million and $23.6 million to the carrying value of long-term investments for the years ended December 31, 2016, 2017 and 2018, respectively.

Business combination

Business combinations are recorded using the purchase method of accounting, and the cost of an acquisition is measured as the aggregate of the fair values at the date of exchange of the assets given, liabilities incurred, and equity instruments issued as well as the contingent considerations and all contractual contingencies as of the acquisition date. The costs directly attributable to the acquisition are expensed as incurred. Identifiable assets, liabilities and contingent liabilities acquired or assumed are measured separately at their fair value as of the acquisition date, irrespective of the extent of any non-controlling interests. The excess of the (i) the total of consideration paid, fair value of the non-controlling interests and acquisition date fair value of any previously held equity interest in the subsidiary acquired over (ii) the fair value of the identifiable net assets of the subsidiary acquired is recorded as goodwill. If the consideration of acquisition is less than the fair value of the net assets of the subsidiary acquired, the difference is recognized directly in the consolidated statements of comprehensive income.

Long-lived assets

Property and equipment

Property and equipment are stated at cost less accumulated depreciation, amortization and impairment, if any. Depreciation is computed using the straight-line method over the estimated useful lives of the assets, generally from three to four years for computers and equipment and five years for furniture and fixtures. Leasehold improvements are amortized over the shorter of the estimated useful lives of the assets or the remaining lease term. Depreciation expenses were $13.3 million, $14.7 million and $18.5 million for the years ended December 31, 2016, 2017 and 2018, respectively.

Goodwill

Goodwill represents the excess of the purchase price over the fair value of the identifiable assets and liabilities acquired as a result of the Group’s acquisitions of interests in its subsidiaries and consolidated VIE. The Group assesses goodwill for impairment in accordance with ASC Subtopic 350-20 (“ASC 350-20”), Intangibles - Goodwill and Other: Goodwill, which requires that goodwill be tested for impairment at the reporting unit level at least annually and more frequently upon the occurrence of certain events, as defined by ASC 350-20. US GAAP provides the option to apply the qualitative assessment first and then the quantitative assessment, if necessary, or to apply the quantitative assessment directly. The qualitative approach starts the goodwill impairment test by assessing qualitative factors, which by taking into consideration of macroeconomics, overall financial performance, industry and market conditions and the share price of the Group, to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount. If so, the quantitative impairment test is performed; otherwise, no further testing is required. When the Group performs the quantitative impairment test, the Group firstly determines whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount. For those reporting units where it is determined that it is more likely than not that their fair values are less than the units’ carrying amounts, the Group performs the second step of a two-step quantitative goodwill impairment test to allocate the fair value of reporting units to all of the assets and liabilities of that unit (including any unrecognized intangible assets) as if the reporting unit had been acquired in a business combination. Application of a goodwill impairment test requires significant management judgment, including the identification of reporting units, assigning assets and liabilities to reporting units, assigning goodwill to reporting units, and determining the fair value of each reporting unit. Judgment in estimating the fair value of reporting units includes estimating future cash flows, determining appropriate discount rates and making other assumptions. Changes in these estimates and assumptions could materially affect the determination of fair value for each reporting unit.

Intangible assets other than goodwill

Intangible assets arising from acquisitions are recognized at fair value upon acquisition and amortized on a straight-line basis over their estimated useful lives, generally from five to ten years. Long-lived assets and certain identifiable intangible assets other than goodwill to be held and used are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. Determination of recoverability is based on an estimate of undiscounted future cash flows resulting from the use of the asset and its eventual disposition. Measurement of any impairment loss for long-lived assets and certain identifiable intangible assets that management expects to hold or use is based on the amount by which the carrying value exceeds the fair value of the asset. Judgment is used in estimating future cash flows, determining appropriate discount rates and making other assumptions. Changes in these estimates and assumptions could materially affect the determination of the asset’s fair value.

Convertible debt

The Group determines the appropriate accounting treatment of its convertible debt in accordance with the terms in relation to the conversion feature. After considering the impact of such features, the Group may account for such instrument as a liability in its entirety, or separate the instrument into debt and equity components following the respective guidance described under ASC 815 Derivatives and Hedging and ASC 470 Debt.

The debt discount, if any, together with related issuance cost are subsequently amortized as interest expense over the contractual life. The Group presented the issuance costs of debt as a direct deduction from the related debt during the periods presented.

Deferred revenues

Deferred revenues consist of contractual billings in excess of recognized revenue and payments received in advance of revenue recognition, which are mainly from the customer advance of the advertising and marketing services and the sales of the fee-based services, such as VIP membership, live streaming, and virtual currency or in-game virtual items sold for game related services.

Non-controlling interests

For the Company’s majority-owned subsidiaries and VIE, non-controlling interests are recognized to reflect the portion of their equity that is not attributable, directly or indirectly, to the Company as the controlling shareholder. To reflect the economic interest held by non-controlling shareholders, net loss attributable to the non-controlling ordinary shareholders is recorded as non-controlling interests in the Company’s consolidated statements of comprehensive income. Non-controlling interests are classified as a separate line item in the equity section of the Company’s consolidated balance sheets and have been separately disclosed in the Company’s consolidated financial statements to distinguish the interests from that of the Company.

Foreign currency

The Company’s reporting currency and functional currency are the U.S. dollar. The Group’s operations in China and in international regions use their respective currencies as their functional currencies. The financial statements of these subsidiaries are translated into U.S. dollars using period-end rates of exchange for assets and liabilities and average rates of exchange in the period for revenues, costs and expenses. Translation gains and losses are recorded in accumulated other comprehensive income (loss) as a component of shareholders’ equity. Translation gains or losses are not released to net income unless the associated net investment has been sold, liquidated, or substantially liquidated.

Foreign currency transactions denominated in currencies other than the functional currency are translated into the functional currency using the exchange rate prevailing on the transactions dates. Monetary assets and liabilities denominated in foreign currencies are translated into the functional currency using the applicable exchange rates at the balance sheet dates. Net gains and losses resulting from foreign exchange transactions are included in interest and other income, net.

Foreign currency translation adjustments included in the Group’s consolidated statements of comprehensive income for the years ended December 31, 2016, 2017, and 2018 were loss of $18.9 million, gain of $37.8 million, and loss of $60.3 million, respectively. Net foreign currency transaction gains or losses arise from transacting in a currency other than the functional currency of the entity and the amounts recorded were immaterial for each of the periods presented.

Net Income per share

Basic net income per share is computed using the weighted average number of ordinary shares outstanding during the period. Options and RSUs are not considered outstanding in computation of basic earnings per share. Diluted net income per share is computed using the weighted average number of ordinary shares and potential ordinary shares outstanding during the period, which include options to purchase ordinary shares, restricted share units and conversion of the convertible debt. The computation of diluted net income per share does not assume conversion, exercise, or contingent issuance of securities that would have an anti-dilutive effect (i.e. an increase in earnings per share amounts or a decrease in loss per share amounts) on net income per share. The Group uses the two-class method to calculate net income per share though both classes share the same rights in dividends. Therefore, basic and diluted earnings per share are the same for both classes of ordinary shares.

Segment reporting

In accordance with ASC 280, Segment Reporting, the Group’s chief operating decision maker (“CODM”), the Chief Executive Officer, reviews the consolidated results when making decisions about allocating resources and assessing performance of the Group as a whole. The Group currently operates and manages its business in two principal business segments globally—advertising and marketing services and value-added services. Information regarding the business segments provided to the Group’s CODM is at the revenue level and the Group currently does not allocate operating costs or assets to its segments, as its CODM does not use such information to allocate resources or evaluate the performance of the operating segments. As the Group’s long-lived assets are substantially all located in the PRC and substantially the Group’s revenues are derived from within the PRC, no geographical information is presented.

Concentration of risks

Concentration of credit risk. Financial instruments that potentially subject the Group to a concentration of credit risk consist primarily of cash and cash equivalents, short-term investments and accounts receivable. In addition, with the majority of its operations in China, the Group is subject to RMB currency risk and offshore remittance risk, both of which have been difficult to hedge and the Group has not done so. The Group limits its exposure to credit loss by depositing its cash and cash equivalents with financial institutions in the US, PRC and Hong Kong, which are among the largest and most respected with high ratings from internationally-recognized rating agencies, that management believes are of high credit quality. The Group periodically reviews these institutions’ reputations, track records and reported reserves.

As of December 31, 2017 and 2018, the Group had $1.79 billion and $1.73 billion, respectively, in cash and bank time deposits (with terms generally up to twelve months) with large domestic banks in China. China promulgated a Bankruptcy Law that came into effect on June 1, 2007, which contains a separate article expressly stating that the State Council may promulgate implementation measures for the bankruptcy of Chinese banks based on the Bankruptcy Law. Under the Bankruptcy Law, a Chinese bank may go bankrupt. In addition, since China’s concession to WTO, foreign banks have been gradually permitted to operate in China and have become significant competitors to Chinese banks in many aspects, especially since the opening of RMB business to foreign banks in late 2006. Therefore, the risk of bankruptcy on Chinese banks in which the Group holds cash and bank deposits has increased. In the event that a Chinese bank that holds the Group’s deposits goes bankrupt, the Group is unlikely to claim its deposits back in full, since it is unlikely to be classified as a secured creditor to the bank under the PRC laws.

Alibaba accounted for 9%, 7% and 7% of the Group’s revenues for the years ended December 31, 2016, 2017 and 2018, respectively. No other customer nor advertising agency accounted for 10% or more of the Group’s revenues. The Group’s top 10 advertising agencies contributed to 22%, 23%, and 26% of the Group’s revenues for the years ended December 31, 2016, 2017, and 2018, respectively.

As of December 31, 2017 and 2018, substantially all accounts receivable were derived from the Group’s China operations. Excluding accounts receivable due from Alibaba and other related parties, accounts receivable primarily consists of amounts due from advertising agencies and direct customers. Alibaba accounted for 25% and 13%, respectively, of the Group's net accounts receivables as of December 31, 2017 and 2018, while one customer accounted for 10% and 6%, and another one accounted for 6% and 22%, respectively, at the same dates.

Concentration of foreign currency risks. The majority of the Group’s operations were in RMB. As of December 31, 2017 and 2018, the Group’s cash, cash equivalents and short-term investments balance denominated in RMB was $871.2 million and $950.8 million, accounting for 49% and 52% of the Group’s total cash, cash equivalents and short-term investments balance. As of December 31, 2017 and 2018, the Group’s aggregate net accounts receivable balance (including accounts receivable due from third parties, Alibaba and other related parties) denominated in RMB was $170.1 million and $368.8 million, respectively, accounting for almost all of its net accounts receivable balance. As of December 31, 2017 and 2018, the Group’s current liabilities balance denominated in RMB was $475.6 million and $620.4 million, accounting for 98% and 99% of its total current liabilities balance. Accordingly, the Group may experience economic losses and negative impacts on earnings and equity as a result of exchange rate fluctuations of the RMB. Moreover, the Chinese government imposes controls on the convertibility of the RMB into foreign currencies and, in certain cases, the remittance of currency out of the PRC. The Group may experience difficulties in completing the administrative procedures necessary to remit its RMB out of the PRC and convert it into foreign currency.

Recent accounting pronouncements

In February 2016, the FASB issued a new standard on leases, ASU 2016-02, which requires that a lessee recognize the assets and liabilities that arise from operating leases. A lessee should recognize a liability to make lease payments (the Lease Liability) and a right-of-use asset representing its right to use the underlying asset for the lease term in the statements of financial position. For leases with a term of 12 months or less, a lessee is permitted to make an accounting policy election by class of underlying asset not to recognize lease assets and lease liabilities. In July 2018, the FASB issued an amendment on leases, ASU 2018-11, which provides another transition method in addition to the existing transition methods by allowing entities to initially apply the new leases standard at the effective date and recognize a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. The Group has adopted the new lease standard beginning the first quarter of fiscal year 2019 using the transition method provided by ASU 2018-11 and will not retrospectively adjust the prior comparative periods. The impacts of initially applying the guidance on the opening balance of 2019 mainly were estimated to recognize approximately $10 million to $12 million of leasing related assets and liabilities that arise from its operating leases, respectively.

In June 2016, the FASB issued of ASU 2016-13, "Financial Instruments—Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments", which will be effective for the Group in the fiscal year of 2020. The guidance replaces the incurred loss impairment methodology with an expected credit loss model for which an entity recognizes an allowance based on the estimate of expected credit loss. In November 2018, the FASB issued an amendment of Topic 326, ASU 2018-19, which clarifies that receivables arising from operating leases are not within the scope of Subtopic 326-20 and should be accounted for in accordance with Topic 842, Leases. The Group is currently evaluating the impact of adopting ASU 2016-13 on its consolidated financial statements but does not expect it to have a material impact.

In January 2017, the FASB issued ASU 2017-04, which simplifies the subsequent measurement of goodwill by eliminating Step 2 from the goodwill impairment test. Under the amendments, an entity should perform its annual, or interim, goodwill impairment test by comparing the fair value of a reporting unit with its carrying value, which eliminates the current requirement to calculate a goodwill impairment charge by comparing the implied fair value of goodwill with its carrying amount. The amendments will be effective beginning the first quarter of fiscal year 2020. The Group adopted the guidance on January 1, 2019 on a prospective basis and expects no impact arising from the amendments.

Cash, Cash Equivalents and Short-term Investments

12 Months Ended

Dec. 31, 2018

Cash, Cash Equivalents and Short-term Investments

Cash, Cash Equivalents and Short-term Investments

3. Cash, Cash Equivalents and Short-term Investments

Cash, cash equivalents and short-term investments consist of the following:


	As of December 31,
	2017		2018
	(In thousands)
Cash and cash equivalents:
Cash	$	1,000,953	$	1,234,596

Short-term investments:
Bank time deposits		791,730		591,269

Total cash, cash equivalents and short-term investments	$	1,792,683	$	1,825,865

The carrying amounts of cash, cash equivalents and short-term investments approximate fair value. Interest income was $7.6 million, $19.5 million and $58.0 million for the years ended December 31, 2016, 2017 and 2018, respectively. The maturity dates for the time deposits were within one year.

Long-term Investments

12 Months Ended

Dec. 31, 2018

Long-term Investments

Long-term Investments

4. Long-term Investments

Long-term investments comprised of investments in publicly traded companies, privately held companies, and limited partnerships. The following sets forth the changes in the Group’s long-term investments:


	Cost Method/
	Equity Securities				Available-for-Sale
	Without Readily				Securities/
	Determinable Fair				Readily Determinable
	Values		Equity Method		Fair Values		Total
	(In thousands)
Balance at December 31, 2015	$	281,707	$	141	$	12,831	$	294,679
Investments made/transfers from prepayments		147,767		4,324		—		152,091
Loss from equity method investment		—		(130)		—		(130)
Disposal of investments		(6,010)		—		(5,000)		(11,010)
Impairment on investments		(31,586)		—		—		(31,586)
Unrealized loss		—		—		(2,557)		(2,557)
Currency translation adjustment		(1,548)		(6)		—		(1,554)

Balance at December 31, 2016	$	390,330	$	4,329	$	5,274	$	399,933
Investments made/transfers from prepayments		31,776		22,307		—		54,083
Gain from equity method investment		—		1,030		—		1,030
Dividend received from equity method investment		—		(267)		—		(267)
Impairment on investments		(4,747)		—		—		(4,747)
Unrealized loss		—		—		(995)		(995)
Currency translation adjustment		2,997		303		—		3,300

Balance at December 31, 2017	$	420,356	$	27,702	$	4,279	$	452,337
Investments made/transfers from prepayments		134,797		97,337		—		232,134
Gain from equity method investment		—		57		—		57
Dividend received from equity method investment		—		(657)		—		(657)
Disposal of investments		—		(1,623)		—		(1,623)
Impairment on investments		(23,557)		—		—		(23,557)
Fair value change through earnings (including adjustment of subsequent price changes)		42,877		—		(2,803)		40,074
Currency translation adjustment		(3,854)		(325)		—		(4,179)

Balance at December 31, 2018	$	570,619	$	122,491	$	1,476	$	694,586

The Group used measurement alternative for recording equity investments without readily determinable fair values at cost, less impairment, adjusted for subsequent observable price changes. Based on ASU 2016-01, entities that elect the measurement alternative will report changes in the carrying value of the equity investments in current earnings. If measurement alternative is used, changes in the carrying value of the equity investment will be recognized whenever there are observable price changes in orderly transactions for the identical or similar investment of the same issuer.

The following table summarizes the total carrying value of the equity investments accounted for under the measurement alternative as of December 31, 2018 including cumulative unrealized upward and downward adjustments made to the initial cost basis of the securities (in thousands):


Initial cost basis	$	555,153
Upward adjustments		42,877
Impairment		(23,557)
Foreign currency translation		(3,854)
Total carrying value at the end of the period	$	570,619

The Group recorded $42.9 million gains (only cumulative upward adjustment) from investments, which were based on identified observable price changes during 2018, indicated by new issuance of identical securities of the same investee or transactions of identical securities by other existing shareholders. The Group did not dispose any interests of these investments and all of the gains were unrealized as of December 31, 2018. The Group classifies the valuation techniques on those investments that use similar identifiable transaction prices as Level 2 of fair value measurements. The Group recognized $23.6 million impairment charge, and recorded no other downward adjustment to investments without readily determinable fair value for the year ended December 31, 2018.

For the year ended December 31, 2018, the Group made investments in private high tech companies totaling $134.8 million, which were accounted for under investments without readily determinable fair values. These investments were made, in general to expand and strengthen the Group’s ecosystem. The Group also made investment in limited partnerships of $97.3 million in 2018, which were accounted for under equity method. These investments mainly included a $48.0 million and a $45.0 million investment in two investing funds.

Investments in marketable equity securities are valued using the market approach based on the quoted prices in active markets at the reporting date. The Group made a $15.1 million investment in 2014 and accounted for it as an AFS investment. In 2016, the Group disposed part of the investment and recognized an impairment charge of $4.8 million to net income, based on the severity and duration of the decline from the carrying value. As of December 31, 2017, the fair value of the AFS investment was $4.3 million. Due to the adoption of ASU 2016-01, the AFS was reclassified to investment with readily determinable fair values beginning January 1, 2018, the Group recorded $2.8 million loss, which is unrealized in 2018, and the fair value was $1.5 million as of December 31, 2018.

The following table shows the carrying amount and fair value of the marketable security:


			Gross		Gross
	Cost		Unrealized		Unrealized		Fair
	Basis		Gains		Losses		Value
	(In thousands)
One marketable security	$	5,274	$	—	$	(995)	$	4,279
December 31, 2017	$	5,274	$	—	$	(995)	$	4,279
One marketable security	$	5,274	$	—	$	(3,798)	$	1,476
December 31, 2018	$	5,274	$	—	$	(3,798)	$	1,476

The Group recorded impairment charges of $40.2 million, $4.7 million, and $24.1 million on its long-term investments and prepayment for the years ended December 31, 2016, 2017 and 2018, respectively, as a result of the investments not performing to expectation or them becoming incapable of making repayment. These included write-offs of prepayments of $3.8 million and $0.5 million in 2016 and 2018, respectively. The investment impairment in 2016 included a $19.0 million write-off on an online-to-offline business and a $10.5 million write-off on an employment-oriented social company. The investment impairment in 2018 included an $11.9 million write-off on an online-reading business and a $9.7 million write-off on a company operating in game business.

Acquisitions, Goodwill and Intangible Assets

12 Months Ended

Dec. 31, 2018

Acquisitions , Goodwill and Intangible Assets

Acquisitions, Goodwill and Intangible Assets

5. Acquisitions , Goodwill and Intangible Assets

On October 1, 2018(“Acquisition Date”), the Group entered into a series of business and asset transfer agreements with Yixia Tech Co., Ltd. (“Yixia Tech”) to acquire the whole of the live streaming business of Yizhibo, which was previously operated by Yixia Tech. The acquisition included the Yizhibo APP and related assets/technology, employees and business contracts with a cash consideration of US$50 million. As of December 31, 2018, the Group had paid $40.0 million to Yixia Tech, with the final $10.0 million scheduled to be paid in 2019. The Group has engaged an independent valuation firm to help management determine the value of assets and liabilities from the acquisition. Total identifiable intangible assets acquired on acquisition date included supplier-relationship of $9.7 million with estimated useful life of five years, core technology of $6.6 million with estimated useful life of eight years, and trademark and domain name of $5.6 million with estimated useful life of ten years. The Group had one immaterial acquisition in 2017. No new acquisition incurred in 2016.

The consideration of acquisition of Yizhibo was allocated based on their fair value of the assets acquired and the liabilities assumed as follows:


	As of Acquisition Date
	(In thousands)
Consideration	$	50,000

Property and equipment, net		466
Identifiable intangible assets acquired		21,942
Other tangible assets		2,874
Liabilities assumed		(2,434)
Goodwill		27,152
Total	$	50,000

The acquisition mentioned above resulted in an increase of $28.0 million to revenues and an immaterial impact to net income for 2018. It did not have a material impact on the Group’s consolidated financial statements; therefore, pro forma disclosures have not been presented.

The following sets forth the changes in the Group’s goodwill by segment:


	Advertising &		Value-added
	Marketing		services		Total
	(In thousands)
Balance as of December 31, 2016	$	—	$	10,266	$	10,266
New acquisition		—		2,318		2,318
Currency translation adjustment		—		836		836
Balance as of December 31, 2017	$	—	$	13,420	$	13,420
Acquisition of Yizhibo		27,152		—		27,152
Impairment		—		(10,554)		(10,554)
Currency translation adjustment		3		(675)		(672)
Balance as of December 31, 2018	$	27,155	$	2,191	$	29,346

The Group performs at least annually a qualitative analysis on the goodwill arising from acquisitions taking into consideration the events and circumstances listed in ASC350 Intangibles—Goodwill and Other , including consideration of macroeconomic factors, industry and market conditions, share price of the Group, and overall financial performance, in addition to other entity-specific factors. Based on the analysis, the Group recognized in 2018 an impairment charge of $10.6 million for the goodwill arising from certain acquisitions made under value-added services segment due to the unsatisfactory financial performance and not optimistic forecast of future revenues. No impairment provision was made for the years ended December 31, 2016 and 2017.

The following table summarizes the Group’s intangible assets arising from acquisitions:


	As of December 31, 2017						As of December 31, 2018
			Accumulated						Accumulated
	Cost		Amortization		Net		Cost		Amortization		Net
	(In thousand)						(In thousand)
Technology	$	2,533	$	(2,062)	$	471	$	8,978	$	(2,594)	$	6,384
Trademark and Domain name		—		—		—		5,623		(147)		5,476
Supplier-relationship		—		—		—		9,738		(495)		9,243
Others		2,460		(2,414)		46		2,326		(2,326)		—
Total	$	4,993	$	(4,476)	$	517	$	26,665	$	(5,562)	$	21,103

As of December 31, 2018, the Group’s intangible assets totaled $21.1 million, mainly consisted of technology, trademark and domain name, and supplier-relationship from the Yizhibo acquisition. The amortization expense for the years ended December 31, 2016, 2017 and 2018 was $0.7 million, $0.6 million and $1.3 million, respectively. As of December 31, 2018, estimated amortization expenses for future periods are expected as follows:


Year Ended December 31,	(In thousands)
2019	$	3,364
2020		3,364
2021		3,364
2022		3,364
2023 and thereafter		7,647
Total expected amortization expense	$	21,103

Stock-Based Compensation

12 Months Ended

Dec. 31, 2018

Stock-Based Compensation

Stock-Based Compensation

6. Stock-Based Compensation

In August 2010, the Company adopted the 2010 Share Incentive Plan (the “2010 Plan”), which has a term of ten years and permits the grant of options, share appreciation rights, restricted shares and restricted share units of the Company to employees, directors and consultants of the Company and its affiliates. Under the plan, a total of 35 million ordinary shares were initially reserved for issuance. The maximum number of ordinary shares available for issuance will be reduced by one share for every one share issued pursuant to a share option or share appreciation right and by 1.75 share for every one share issued as restricted shares or pursuant to a restricted shares unit. In March 2014, the 2010 Plan was terminated and all remaining shares were forwarded to the 2014 Plan.

In March 2014, the Company adopted the 2014 Share Incentive Plan (the “2014 Plan”), which was funded by the remaining 4.6 million shares from the 2010 Plan plus an additional 1.0 million shares. On January 1, 2015, shares in the 2014 Plan, which have a term life of ten years, were allowed a one-time increase in the amount equal to 10% of the total number of Weibo shares issued and outstanding on a fully-diluted basis as of December 31, 2014. Each share in the 2014 Plan pool allows for a grant of a restricted share unit or option share. The Company intends to use such share incentive plan to attract and retain employee talent.

The following table sets forth the stock-based compensation included in each of the relevant accounts:


	Year Ended December 31,
	2016		2017		2018
	(In thousands)
Cost of revenues	$	2,616	$	3,716	$	3,522
Sales and marketing		5,357		8,264		6,837
Product development		15,076		21,879		21,187
General and administrative		13,853		14,178		9,465
	$	36,902	$	48,037	$	41,011

Stock based compensation related to the grants were amortized generally over four years on a straight-line basis with $36.9 million, $48.0 million and $41.0 million expensed for the years ended December 31, 2016, 2017 and 2018, respectively.

The following table sets forth a summary of the number of shares available for issuance:


		Shares Available
		(In thousands)
December 31, 2015		20,217
Addition		—
Granted*		(1,917)
Cancelled/expired/forfeited		578

December 31, 2016		18,878
Addition		—
Granted*		(736)
Cancelled/expired/forfeited		398

December 31, 2017		18,540
Addition		—
Granted*		(1,597)
Cancelled/expired/forfeited		350

December 31, 2018		17,293

*For the years ended December 31, 2016, 2017 and 2018, 1.9 million, 0.7 million and 1.6 million restricted share units were granted under the 2014 Plan, respectively. No options were granted for the three-year period ended December 31, 2018.

Stock Options

The following table sets forth a summary of option activities under the Company’s stock option program:


				Weighted Average
	Options	Weighted Average		Remaining	Aggregate
	Outstanding	Exercise Price		Contractual Life	Intrinsic Value
	(In thousands)			(In years)	(In thousands)
December 31, 2015	6,303	$	1.26	2.4	$	114,975
Granted	—	$	—
Exercised	(3,625)	$	1.10
Cancelled/expired/forfeited	(91)	$	3.37

December 31, 2016	2,587	$	1.41	1.6	$	101,403
Granted	—	$	—
Exercised	(2,122)	$	1.04
Cancelled/expired/forfeited	(28)	$	0.68

December 31, 2017	437	$	3.24	2.0	$	43,800
Granted	—	$	—
Exercised	(248)	$	3.14
Cancelled/expired/forfeited	(5)	$	1.16

December 31, 2018	184	$	3.45	1.5	$	10,089

Vested and expected to vest as of December 31, 2017	437	$	3.24	2.0	$	43,800
Exercisable as of December 31, 2017	437	$	3.24	2.0	$	43,800

Vested and expected to vest as of December 31, 2018	184	$	3.45	1.5	$	10,089
Exercisable as of December 31, 2018	184	$	3.45	1.5	$	10,089

The total intrinsic value of options exercised for the years ended December 31, 2016, 2017 and 2018 was $129.3 million, $135.2 million and $25.6 million, respectively. The intrinsic value is calculated as the difference between the market value on the date of exercise and the exercise price of the shares. As reported by the NASDAQ Global Selected Market, the Company’s ending stock price as of December 31, 2016, 2017 and 2018 was $40.60, $103.46 and $58.43, respectively. Cash received from the exercise of stock option during the years ended December 31, 2016, 2017 and 2018 was $4.2 million, $2.3 million and $0.8 million, respectively.

As all compensation cost related to stock options has been fully amortized in 2017, there is no remaining unrecognized compensation.

Information regarding stock options outstanding is summarized below:


		Weighted			Weighted		Weighted Average
	Options	Average		Options	Average		Remaining
Range of Exercise Prices	Outstanding	Exercise Price		Exercisable	Exercise Price		Contractual Life
	(In thousands)			(In thousands)			(In years)
As of December 31, 2017
$ 0.96 - $1.80	31	$	0.97	31	$	0.97	0.2
$ 3.25 - $3.36	179	$	3.33	179	$	3.33	1.4
$ 3.43 - $3.50	227	$	3.48	227	$	3.48	2.6
	437	$	3.24	437	$	3.24	2.0

As of December 31, 2018
$ 3.25 - $3.36	32	$	3.30	32	$	3.30	0.8
$ 3.43 - $3.50	152	$	3.48	152	$	3.48	1.7
	184	$	3.45	184	$	3.45	1.5

Restricted Share Units

Summary of Performance-Based Restricted Share Units

The following table sets forth a summary of performance-based restricted share unit activities:


		Weighted-Average
		Grant Date
	Shares Granted	Fair Value
	(In thousands)
December 31, 2015	—	$	—
Awarded	111	$	27.00
Cancelled	(3)	$	27.00

December 31, 2016	108	$	27.00
Awarded	155	$	50.45
Vested	(102)	$	27.00
Cancelled	(32)	$	46.42

December 31, 2017	129	$	50.32
Awarded	191	$	86.63
Vested	(126)	$	50.32
Cancelled	(190)	$	86.90

December 31, 2018	4	$	87.14

As of December 31, 2017 and 2018, unrecognized compensation cost, adjusted for estimated forfeitures, related to performance-based restricted share units granted to the Company’s employees was $0.7 million and $0.02 million, respectively.

Summary of Service-Based Restricted Share Units

The following table sets forth a summary of service-based restricted share unit activities:


		Weighted-
		Average
	Shares	Grant Date
	Granted	Fair Value
	(In
	thousands)
December 31, 2015	6,501	$	13.98
Awarded	1,806	$	24.94
Vested	(2,274)	$	14.73
Cancelled	(575)	$	14.58

December 31, 2016	5,458	$	17.23
Awarded	581	$	62.87
Vested	(2,406)	$	17.01
Cancelled	(366)	$	17.72

December 31, 2017	3,267	$	25.45
Awarded	1,406	$	68.18
Vested	(1,757)	$	21.59
Cancelled	(160)	$	44.00

December 31, 2018	2,756		48.62

As of December 31, 2018, unrecognized compensation cost, adjusted for estimated forfeitures and related to non-vested, service-based restricted share units granted to the Company’s employees and directors, was $112.5 million. This cost is expected to be recognized over a weighted-average period of 3.5 years. The total fair value based on the vesting date of the restricted share units vested was $33.5 million, $40.9 million and $37.9 million for the years ended December 31, 2016, 2017 and 2018, respectively.

Other Balance Sheet Components

12 Months Ended

Dec. 31, 2018

Other Balance Sheet Components

Other Balance Sheet Components

7. Other Balance Sheet Components


	As of December 31,
	2016	2017		2018
	(In thousands)
Accounts receivable, net:
Due from third parties	—	$	105,686	$	201,835
Due from Alibaba	—		42,832		48,222
Due from other related parties	—		29,696		131,465

Total gross amount	—	$	178,214	$	381,522
Allowance for doubtful accounts:
Balance at the beginning of the year	(1,375)		(6,529)		(8,114)
Reversal (additional provision) charged to expenses, net	(7,787)		(5,478)		(6,226)
Write-off	2,633		3,893		1,911

Balance at the end of the year	(6,529)		(8,114)		(12,429)
	—	$	170,100	$	369,093

Prepaid expenses and other current assets:
Rental and other deposits	—	$	2,233	$	684
Deductable value-added taxes	—		—		4,539
Prepayment for investments	—		20,881		106,256
Advertising prepayment	—		3,959		4,575
Prepayment to outsourced service providers	—		5,369		4,730
Amounts deposited by users*	—		25,277		30,631
Content fees	—		7,393		11,021
Others	—		4,121		6,385
	—	$	69,233	$	168,821

Property and equipment, net:
Computers and equipment	—	$	113,558	$	124,241
Leasehold improvements	—		4,321		5,008
Furniture and fixtures	—		1,241		1,677
Others	—		2,574		2,696

Property and equipment, gross	—		121,694		133,622
Less: Accumulated depreciation	—		(87,901)		(87,999)
	—	$	33,793	$	45,623

Accrued and other liabilities**:
Payroll and welfare	—	$	57,848	$	56,349
Marketing expenses	—		53,380		49,998
Payroll withholding taxes	—		3,547		3,547
Sales rebates	—		60,663		95,121
Professional fees	—		6,170		8,249
VAT and other tax payable	—		51,563		48,651
Payable to other service providers	—		362		1,266
Amounts due to users*	—		25,277		30,631
Unpaid consideration for acquisition	—		—		10,000
Others	—		9,805		13,625
	—	$	268,615	$	317,437

* Weibo wallet enables users to conduct interest-generation activities on Weibo, such as handing out "red envelopes" and coupons to users and purchase different types of products and services on Weibo, including those offered by the Group, such as marketing services and VIP membership, and those offered by Weibo’s platform partners, such as e-commerce merchandises, financial products and virtual gifts. Amounts deposited by users primarily represent the receivables temporarily held in Weibo’s account on a third party online payment platform for Weibo wallet users. Amounts due to users represent the balances that are payable on demand to Weibo wallet users and therefore are reflected as current liability on the consolidated balance sheets.

** Include amounts due to third parties, employees, related parties (see Note 9) and Weibo wallet users.

Income Taxes

12 Months Ended

Dec. 31, 2018

Income Taxes

Income Taxes

8. Income Taxes

The Company is registered in the Cayman Islands and mainly operates in two taxable jurisdictions—the PRC and Hong Kong.

The Group’s income before income taxes is as follows:


	Year Ended December 31,
	2016			2017			2018
	(In thousands, except percentage)
Income before income tax expenses	$	109,980		$	417,111		$	668,842
Add: loss from non-China operations	$	60,193		$	52,261		$	43,266
Income from China operations	$	170,173		$	469,372		$	712,108
Income tax expense applicable to China operations	$	4,316		$	66,746		$	96,222
Effective tax rate for China operations		2.5	%		14.2	%		13.5	%

The Company generated the majority of its operating income from PRC operations and has recorded income tax provision for the periods presented. Stock-based compensation was recorded in the Company’s loss from non-China operations. Loss from non-China operations in 2016 included a loss of $23.8 million from investment impairments.

Commencing on January 1, 2018, in order to enhance comparability with industry peers, income taxes payable has been presented as a single line item in balance sheet as opposed to being part of accounts payable. To conform to current period presentation, the relevant amount of $70.9 million as of December 31, 2017 has been reclassified. The impact to consolidated statement of cash flows was a reclassification of $5.1 million, $62.3 million and $21.0 million from accounts payable to income taxes payable included in operating activities for the years ended December 31, 2016, 2017 and 2018, respectively.

Cayman Islands

Under the current tax laws of the Cayman Islands, the Company is not subject to tax on income or capital gain. In addition, upon payments of dividends by the Company to its shareholders, no Cayman Islands withholding tax is required.

Hong Kong

Weibo HK is subject to taxes in Hong Kong at 16.5% for all the periods presented. As of December 31, 2018, the Company’s Hong Kong subsidiary had a net operating loss of $1.4 million, which can be carried forward indefinitely to offset future taxable income. Also as of December 31, 2018, deferred tax assets of Weibo HK consist mainly of net operating loss carried forward, for which a full valuation allowance was provided. Management believes it is more likely than not that these assets will not be realized in the future.

China

Effective January 1, 2008, the Enterprise Income Tax Law (the “EIT Law”) in China unifies the enterprise income tax rate for the entities incorporated in China at 25%, unless they are eligible for preferential tax treatment. On February 22, 2008, relevant governmental regulatory authorities released the qualification criteria, application procedures and assessment processes for “software enterprise,” which can enjoy an income tax exemption for two years beginning with its first profitable year and a 50% tax reduction, at a rate of 12.5% for the subsequent three years. The Group’s WFOE qualifies as a software enterprise and, thus, enjoyed an income tax exemption in 2015 and 2016, and a reduced enterprise income tax rate of 12.5% in 2017 and 2018. In late 2018, Weibo Technology was approved to be qualified as a “key software enterprise” for 2017 and was entitled to enjoy a further reduced preferential tax rate of 10% for 2017. Weibo Technology used the preferential tax treatment of its “key software enterprise” status of 2017 in 2018. The qualification as a “key software enterprise” is subject to annual evaluation and approval by the relevant authorities in China and the Group will only recognize the preferential tax treatment of “key software enterprise” status when approval from the relevant authorities is obtained.

The EIT Law also provides that an enterprise established under the laws of a foreign country or region but whose “de facto management body” is located in the PRC be treated as a resident enterprise for PRC tax purposes and consequently be subject to the PRC income tax at the rate of 25% for its global income. The Implementing Rules of the EIT Law merely define the location of the “de facto management body” as “the place where the exercising, in substance, of the overall management and control of the production and business operation, personnel, accounting, properties, etc., of a non-PRC company is located.” Based on a review of surrounding facts and circumstances, the Group does not believe that it is likely that its operations outside of the PRC be considered a resident enterprise for PRC tax purposes. However, due to limited guidance and implementation history of the EIT Law, should Weibo be treated as a resident enterprise for PRC tax purposes, the Company will be subject to PRC tax on worldwide income at a uniform tax rate of 25% retroactive to January 1, 2008.

The EIT Law also imposes a withholding income tax rate of 10% on dividends distributed by a WFOE to its immediate holding company outside of China, if such immediate holding company is considered as a non-resident enterprise without any establishment or place within China or if the received dividends have no connection with the establishment or place of such immediate holding company within China, unless such immediate holding company’s jurisdiction of incorporation has a tax treaty with China that provides for a different withholding arrangement. The Cayman Islands, where the Company incorporated, does not have such tax treaty with China. According to the arrangement between Mainland China and Hong Kong Special Administrative Region on the Avoidance of Double Taxation and Prevention of Fiscal Evasion in August 2006, dividends paid by a WFOE in China to its immediate holding company in Hong Kong will be subject to withholding tax at a rate of no more than 5% (if the foreign investor owns directly at least 25% of the shares of the WFOE). The State Administration of Taxation further promulgated Circular 601 on October 27, 2009, which provides that tax treaty benefits will be denied to “conduit” or shell companies without business substance and that a beneficial ownership analysis will be used based on a “substance-over-form” principle to determine whether or not to grant the tax treaty benefits.

The operations of the Group’s WFOE in China is invested and held by Weibo HK. If the Company is regarded as a non-resident enterprise and Weibo HK is regarded as a resident enterprise, then Weibo HK may be required to pay a 10% withholding tax on any dividends payable to the Company. If Weibo HK is regarded as a non-resident enterprise, then Weibo Technology may be required to pay a 5% withholding tax for any dividends payable to Weibo HK. However, it is still unclear at this stage whether Circular 601 applies to dividends from Weibo Technology paid to Weibo HK. If Weibo HK were not considered as “beneficial owners” of any dividends from Weibo Technology, the dividends payable to Weibo HK would be subject to a withholding tax of 10%. In accordance with accounting guidance, all undistributed earnings are presumed to be transferred to Weibo Corporation and are subject to the withholding taxes. The current policy approved by the Company’s board of directors allows the Group to distribute PRC earnings offshore only if the Group does not have to pay a dividend tax. As of December 31, 2018, the Group did not record any withholding tax for its PRC subsidiaries.

Composition of income tax expenses for China operations

The following table sets forth current and deferred portion of income tax expenses of the Company’s China subsidiaries, VIEs and VIEs’ subsidiaries:


	Years Ended December 31,
	2016		2017		2018
		(In thousands)
Deferred tax (benefits)/provisions	$	(4,630)	$	(1,503)	$	4,438
Current income tax expenses		8,946		68,249		91,784

Income tax expenses	$	4,316	$	66,746	$	96,222

Reconciliation of the statutory tax rate to the effective tax rate for China operations

The following table sets forth reconciliation between the statutory EIT rate and the effective tax rate for China operations:


	Year Ended December 31,
	2016		2017		2018
Statutory EIT rate	25.0	%	25.0	%	25.0	%
Effect on tax holiday and preferential tax treatment(1)	(29.6)	%	(11.6)	%	(12.1)	%
Permanent differences	1.2	%	0.2	%	0.6	%
Change in valuation allowance	5.9	%	0.6	%	0.0	%

Effective tax rate for China operations	2.5	%	14.2	%	13.5	%

(1)

Included the impact of Weibo Technology’s preferential tax treatment of “key software enterprise” status of 2017 in 2018.

The provision for income taxes for the years ended December 31, 2016, 2017 and 2018 differs from the amounts computed by applying the statutory EIT rate primarily due to the tax exemption and preferential tax treatment of the WFOE, Weibo Technology, as a qualified software enterprise (key software enterprise status for 2017) for the periods presented. For the year ended December 31, 2016, Weibo Technology was tax exempted for $50.4 million. For the year ended December 31, 2017 and 2018, Weibo Technology enjoyed a tax reduction of $52.6 million and $77.2 million, respectively, due to the preferential tax treatment. It also recognized the preferential tax treatment of $10.8 million of key software enterprise status for 2017 in 2018. The tax exemption and preferential tax treatment in the three-year period ended December 31, 2018 resulted in an effect of $0.23, $0.25 and $0.39 on basic net income per share in 2016, 2017 and 2018, respectively.

Deferred tax assets and liabilities

The following table sets forth the significant components of deferred tax assets and liabilities for China operations:


	As of December 31,
	2017		2018
	(In thousands)
Deferred tax assets:
Net operating loss carry forwards	$	10,280	$	4,180
Less: valuation allowance		(10,280)		(4,180)
Depreciation, accounts receivable, accrued and other liabilities		19,931		25,327
Less: valuation allowance		(11,629)		(13,419)

Net deferred tax assets (included in other assets)	$	8,302	$	11,908

Deferred tax liabilities:
Acquired intangible assets	$	129	$	2,310
Depreciation		527		702
Investment gain		—		9,565
Others		1,224		—

Total deferred tax liabilities	$	1,880	$	12,577

Valuation allowance is provided against deferred tax assets when the Group determines that it is more likely than not that the deferred tax assets will not be utilized in the future. In making such determination, the Group considered factors including (i) future reversals of existing taxable temporary differences; (ii) future taxable income exclusive of reversing temporary differences and carry forwards; and (iii) tax planning strategies. The valuation allowance on deferred tax assets as of December 31, 2017 and 2018 was $21.9 million and $17.6 million, respectively. The change in valuation allowance was primarily due to bad debt expenses, investment impairment charges, as well as the expiration of net operating loss carry forward. Historically, deferred tax assets were valued using the statutory rate of 25%. As of December 31, 2017 and 2018, the Group had net operating loss carry forwards for China operations totaling $41.1 million and $16.7 million, respectively, for which full valuation allowance was provided. In 2018, $18.6 million of the net operating loss carry forwards expired and none was utilized. As of December 31, 2018, the net operating loss resulting from the Company’s carve-out from SINA has fully expired. Net operating loss carry forwards for China operations as of December 31, 2018 will expire, if unused, in the years ending December 31, 2019 through December 31, 2023.

Related Party Transactions

12 Months Ended

Dec. 31, 2018

Related Party Transactions

Related Party Transactions

9. Related Party Transactions

The following sets forth significant related parties and their relationships with the Company:


Company Name		Relationship with the Company
SINA		Parent and affiliates under common control.

Alibaba		Strategic partner and significant shareholder of the Company.

Matching loan between Weibo and SINA.

In January 2017, the Company and its certain subsidiary entered into one-year loan agreements with SINA and SINA subsidiary, pursuant to which the Company is entitled to draw down U.S. dollar-denominated loan from SINA and a SINA subsidiary is entitled to draw down equivalent RMB-denominated loan from the Company's subsidiary, to facilitate each other's business operations. All of the loans carried a fixed rate of interest equal to the current market interest rate as of the dates when the principal was drawn down.

For the year ended December 31, 2017, interest income that the Group earned from such RMB-denominated loans to SINA was $1.7 million, and interest expense that the Group paid for such U.S. dollar-denominated loans from SINA was $1.5 million, respectively. As of December 31, 2017, the Company and its subsidiary have settled both loans with SINA and SINA subsidiary with payment of U.S. dollar-denominated principal and interest expense of $61.5 million and receipt of RMB-denominated principal and interest income of $64.0 million, respectively.

Besides the matching loans, SINA made an additional $2.0 million short-term loan to Weibo in 2017, which was repaid to SINA in 2018. In 2018, the Group entered in to a series of one-year loan agreements with SINA pursuant to which SINA is entitled to borrow from the Group to facilitate SINA's business operations. SINA has withdrawn a total of $149.5 million loan from the Group and repaid $101.1 million to the Group for the year ended December 31, 2018. As of December 31, 2018, the loan to SINA was $43.6 million.

The following sets forth significant related party transactions with the Company:


	Year Ended December 31,
	2016		2017		2018
	(In thousands)
Transactions with SINA
Revenue billed through/for service provided to SINA(1)	$	39,285	$	64,093	$	90,645
Costs and expenses allocated from SINA(2)	$	25,703	$	41,136	$	47,334
Interest income on matching loan to SINA	$	—	$	1,735	$	—
Interest expense on matching loan from SINA	$	—	$	1,537	$	—
Interest income on loans to SINA		—		—		2,425

(1)

For the years ended December 31, 2016, 2017 and 2018, the Group charged $39.3 million, $64.1 million and $90.6 million for services provided to SINA or to third parties billed through SINA, respectively.

(2)

Costs and expenses allocated from SINA represented the charges for certain services provided by SINA’s affiliates and charged to the Group using actual cost allocation based on proportional utilization (see Note 1). In addition to the allocated costs and expenses, SINA also billed $20.3 million, $22.9 million, and $23.4 million for other costs and expenses incurred by Weibo but paid by SINA in 2016, 2017 and 2018, respectively.


	Year Ended December 31,
	2016		2017		2018
	(In thousands)
Transactions with Alibaba
Advertising and marketing services provided to Alibaba	$	57,908	$	84,688	$	117,696
Services provided by Alibaba	$	13,988	$	32,734	$	47,642

The following sets forth related party outstanding balance:


	As of December 31,
	2017		2018
		(In thousands)
Amount due from SINA(3)	$	16,356	$	105,319
Accounts receivable due from Alibaba	$	42,832	$	48,222

(3)The Group uses amount due from/to SINA to settle balances arising from cost and expenses allocated from SINA based on proportional utilization, other expenditures incurred by the Weibo business but paid by SINA and third-party customer and supplier balances settled through SINA, as well as business transactions between Weibo and SINA. As of December 31, 2018, the amount due from SINA also included loans to SINA of $43.6 million at an annual interest rate of 4.8%.

Other related parties mainly include investee companies on which SINA or Weibo has significant influence. These investees are mainly high-tech companies operating in different internet-related industries, such as short video applications, social and new media marketing services and so on. For the years ended December 31, 2016, 2017 and 2018, advertising and marketing revenues generated from other related parties were $45.6 million, $71.6 million and $130.2 million, value-added services revenues from other related parties were $0.6 million, $21.4 million and $24.1 million, and the Group received promotional services from other related parties amounting to approximately $10.6 million, $4.1 million and $9.3 million, respectively. As of December 31, 2017 and 2018, net accounts receivable due from other related parties was $29.7 million and $130.8 million, accounts payable due to other related parties were $12.2 million and $31.2 million, and accrued and other liabilities due to other related parties were $5.0 million and $14.4 million, respectively. Within other related parties, one related party that is an equity investee in the short video business contributed $53.9 million of advertising and marketing revenues in 2018 and represented $80.9 million of accounts receivable due from other related parties at December 31, 2018.

Employee Benefit Plans	12 Months Ended
Employee Benefit Plans	Dec. 31, 2018
Employee Benefit Plans
Employee Benefit Plans	10. Employee Benefit Plans China Contribution Plan The Company’s subsidiaries, VIEs and VIEs’ subsidiaries in China participate in a government-mandated, multi-employer, defined contribution plan, pursuant to which certain retirement, medical, housing and other welfare benefits are provided to employees. Chinese labor laws require the entities incorporated in China to pay to the local labor and welfare authorities a monthly contribution at a stated contribution rate based on the monthly basic compensation of qualified employees. The local labor bureau is responsible for meeting all retirement benefit obligations. The Group has no further commitments beyond its monthly contribution. For the years ended December 31, 2016, 2017 and 2018, the Group’s total contribution was $31.4 million, $38.0 million and $53.7 million, respectively.

Net Income per Share

12 Months Ended

Dec. 31, 2018

Net Income per Share

Net Income per Share

11. Net Income per Share

Basic net income per share is computed using the weighted average number of the ordinary shares outstanding during the period. Options and RSUs are not considered outstanding in the computation of basic earnings per share (“EPS”). Diluted EPS is computed using the weighted average number of ordinary shares and potential ordinary shares outstanding during the period under the treasury stock method. For the years ended December 31, 2016, 2017 and 2018, options to purchase ordinary shares and RSUs of 8.1 million, 4.8 million and 2.2 million, respectively, as well as the number of “if converted” shares related to convertible debt of 6.8 million in 2018, were recognized as dilutive factors and included in the calculation of diluted net income per share. For the years ended December 31, 2016, 2017 and 2018, options and RSUs which were anti-dilutive and excluded from the calculation of diluted net income per share were 0.03 million, nil and 0.06 million, respectively. For the year ended December 31, 2017, 1.2 million shares convertible from the convertible debt were anti-dilutive and excluded from the calculation of diluted net income per share.

The following table sets forth the computation of basic and diluted net income per share for the periods indicated:


	Year Ended December 31,
	2016		2017		2018
	(In thousands, except per share data)
Basic net income per share calculation:
Numerator:
Net income attributable to Weibo	$	108,027	$	352,590	$	571,823
Denominator:
Weighted average ordinary shares outstanding		214,745		220,555		223,751
Basic net income per share attributable to Weibo	$	0.50	$	1.60	$	2.56

Diluted net income per share calculation:
Numerator:
Net income attributable to Weibo	$	108,027	$	352,590	$	571,823
Add: Effect on interest expenses and amortized issuance cost of convertible debt		—		—		15,390
Net income attributable for calculating diluted net income per share		108,027		352,590		587,213
Denominator:
Weighted average ordinary shares outstanding		214,745		220,555		223,751
Weighted average ordinary shares equivalents:
Effects of dilutive securities
Stock options		4,334		1,213		283
Unvested restricted share units		3,780		3,595		1,896
Convertible debt		—		—		6,753
Shares used in computing diluted net income per share attributable to Weibo		222,859		225,363		232,683
Diluted net income per share attributable to Weibo	$	0.48	$	1.56	$	2.52

Segment Information

12 Months Ended

Dec. 31, 2018

Segment Information

Segment Information

12. Segment Information

The Group currently operates and manages its business in two principal business segments globally—advertising and marketing services and value-added services. Information regarding the business segments provided to the Group’s chief operating decision makers (“CODM”), its Chief Executive Officer, is at the revenue level and the Group currently does not allocate operating costs or assets to its segments, as its CODM does not use such information to allocate resources or evaluate the performance of the operating segments. As substantially all of the Group’s revenues are derived from within the PRC and substantially all of the Group’s long-lived assets are located within the PRC, no geographical information is presented.

The following is a summary of the Group’s revenues:


Revenues	Advertising & Marketing		Value-added services		Total
	(In thousand)
Year ended December 31, 2016	$	570,982	$	84,818	$	655,800

Year ended December 31, 2017	$	996,745	$	153,309	$	1,150,054

Year ended December 31, 2018	$	1,499,180	$	219,338	$	1,718,518

Profit Appropriation and Restricted Net Assets	12 Months Ended
Profit Appropriation and Restricted Net Assets	Dec. 31, 2018
Profit Appropriation and Restricted Net Assets
Profit Appropriation and Restricted Net Assets	13. Profit Appropriation and Restricted Net Assets The Company’s subsidiaries, VIEs and VIEs’ subsidiaries in China are required to make appropriations to certain non-distributable reserve funds. In accordance with the laws applicable to China’s WFOE, its subsidiaries have to make appropriations from their after-tax profit (as determined under Generally Accepted Accounting Principles in the PRC (“PRC GAAP”) to non-distributable reserve funds including (i) general reserve fund, (ii) enterprise expansion fund and (iii) staff bonus and welfare fund. General reserve fund is at least 10% of the after-tax profits calculated in accordance with the PRC GAAP. Appropriation is not required if the reserve fund has reached 50% of the registered capital of the respective company. The appropriation of the other two reserve funds is at the Group’s discretion. At the same time, the Company’s VIE, in accordance with the China Company Laws, must make appropriations from their after-tax profit (as determined under the PRC GAAP) to non-distributable reserve funds including (i) statutory surplus fund, and (ii) discretionary surplus fund. Statutory surplus fund is at least 10% of the after-tax profits calculated in accordance with the PRC GAAP. Appropriation is not required if the reserve fund has reached 50% of the registered capital of the respective company. General reserve fund and statutory surplus fund are restricted for set off against losses, expansion of production and operation or increase in registered capital of the respective company. These reserves are not transferable to the Company in the form of cash dividends, loans or advances. These reserves are therefore not available for distribution except in liquidation. As of December 31, 2017 and 2018, the Group accrued approximately $73.6 million and $98.7 million in the reserve fund. Under the PRC laws and regulations, the subsidiaries, VIEs and VIEs’ subsidiaries incorporated in the PRC are restricted in their ability to transfer a portion of their net assets to the Group either in the form of dividends, loans or advances of the consolidated net assets. Even though the Group currently does not require any such dividends, loans or advances from the PRC subsidiaries, VIEs and VIEs’ subsidiaries for working capital and other funding purposes, the Group may in the future require additional cash resources from the PRC subsidiaries, VIEs and VIEs’ subsidiaries due to changes in business conditions, to fund future acquisitions and development, or merely declare and pay dividends to or distribution to its shareholders. Net assets subject to restriction for the Group amounted to $391.5 million, or 22.4% of the Group’s total consolidated net assets as of December 31, 2018.

Fair Value Measurement

12 Months Ended

Dec. 31, 2018

Fair Value Measurement

Fair Value Measurement

14. Fair Value Measurement

The following table summarizes, for assets measured at fair value on a recurring basis, the respective fair value and the classification by level of input within the fair value hierarchy as of December 31, 2017 and 2018:


	Fair Value Measurements
	(in thousands)
			Quoted Prices in
			Active Market		Significant Other		Significant
			for Identical Assets		Observable Inputs		Unobservable Inputs
	Total		(Level 1)		(Level 2)		(Level 3)
As of December 31, 2017:
Bank time deposits*	$	791,730	$	—	$	791,730	$	—
Available-for-sale equity securities**		4,279		4,279		—		—
Total	$	796,009	$	4,279	$	791,730	$	—

As of December 31, 2018:
Bank time deposits*	$	591,269	$	—	$	591,269	$	—
Equity securities with readily determinable market value **		1,476		1,476		—		—
Total	$	592,745	$	1,476	$	591,269	$	—

* Included in short-term investments on the Group’s consolidated balance sheets.

** Included in long-term investments on the Group’s consolidated balance sheets.

Recurring

The Group measures bank time deposits and available-for-sale securities/securities with readily determinable fair values on a recurring basis.

The fair value of the Group’s available-for-sale securities/securities with readily determinable fair values are determined based on the quoted market price (Level 1). The fair value of the Group's bank time deposits are determined based on the quoted market price for similar products (Level 2).

The Group reviews its available-for-sale securities regularly to determine if an investment is impaired due to changes in quoted market price or other impairment indicators prior to 2018. For the years ended December 31, 2016 and 2017, impairment related to available-for-sale securities was $4.8 million and nil, respectively (see Note 4 for further information). With the adoption of new investment guidance under ASC 820, the available-for-sale securities were reclassified as investments with readily determinable fair values beginning January 1, 2018 with their fair value change recognized in earnings immediately. There will no longer be any impairment from an available-for-sale classification for equity securities.

Non-recurring

For those investments without readily determinable fair value, the Group measures them at fair value when observable price changes are identified or impairment charge were recognized. The fair values of the Group’s privately held investments as disclosed are determined based on the discounted cash flow model using the discount curve of market interest rates or based on the similar transaction price in the market directly. The Group classifies the valuation techniques on those investments that use similar identifiable transaction prices as Level 2 of fair value measurements.

The Group measures equity method investments at fair value on a non-recurring basis only if an impairment charge is recognized. As of December 31, 2018, certain privately held investments were measured using significant unobservable inputs (Level 3) and written down from their respective carrying values to fair values, considering the investees’ financial performance, assumptions about future growth, and future financing plan, with impairment charges incurred and recorded in earnings for the year then ended. The impairment charges related to these investments were $35.4 million and $4.7 million for the years ended December 31, 2016 and 2017, respectively. The Group also recognized an impairment charge of $23.6 million for those investments without readily determinable fair values in 2018. The fair value of the privately held investments was measured based on discounted cash flow with unobservable inputs including the discount curve of market interest rates, which ranged from 12% to 20%.

The Group’s non-financial assets, such as intangible assets, goodwill and fixed assets, are measured at fair value only if they were determined to be impaired. In accordance with the Group’s policy to perform an impairment assessment of its goodwill on an annual basis as of the balance sheet date or when facts and circumstances warrant a review, the Group performed an impairment assessment on its goodwill by reporting unit annually. The Group concluded that no write-down was warranted for the years ended December 31, 2016 and 2017, respectively, and made an impairment charge of $10.6 million for the goodwill arising from certain previous acquisitions for the year ended December 31, 2018, and the remaining carrying value was nil after the impairment.

The carrying amount of cash and cash equivalents, short-term investments, accounts receivable due from third parties, accounts receivable due from Alibaba, accounts receivable due from other related parties, amount due from SINA, accounts payable, accrued and other liabilities approximates fair value because of their short-term nature.

Convertible Debt	12 Months Ended
Convertible Debt	Dec. 31, 2018
Convertible Debt
Convertible Debt	15. Convertible Debt In October 2017, the Company issued $900 million in aggregate principal amount of 1.25% coupon interest convertible senior notes due on November 15, 2022 ("2022 Notes") at par. The Notes may be converted into Weibo's American depositary shares ("ADSs"), each representing one Class A ordinary share of the Company, at the option of the holders, which is equivalent to an initial conversion price of approximately US$133.27 per ADS, subject to adjustment. The conversion rate may be adjusted under certain circumstances, such as distribution of dividends and stock splits. In addition, upon a make-whole fundamental change prior to the maturity date of the notes, the Company will, under certain circumstances, increase the applicable conversion rate for a holder that elects to convert its notes in connection with such make-whole fundamental change. The net proceeds to the Company from the issuance of the 2022 Notes were $879.3 million, net of issuance cost of $20.7 million. The Company will pay cash interest at an annual rate of 1.25% on the 2022 Notes, payable semiannually in arrears in cash on May 15 and November 15 of each year, beginning May 15, 2018. The issuance costs of the 2022 Notes are being amortized to interest expense over the contractual life. For the years ended December 31, 2017 and 2018, the 2022 Notes related interest expenses were $2.7 million and $15.4 million, respectively.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2018

Commitments and Contingencies

Commitments and Contingencies

16. Commitments and Contingencies

Operating lease commitments include the commitments under the lease agreements for the Group’s office premises. The Group leases its office facilities under non-cancelable operating leases with various expiration dates through 2023. For the years ended December 31, 2016, 2017 and 2018, lease expense was $14.4 million, $9.2 million and $11.2 million, respectively. Based on the current rental lease agreements, future minimum lease payments commitments as of December 31, 2018 were as follows:


			Less than One		One to		Three to		More than
Operating lease commitments	Total		Year		Three Years		Five Years		Five Years
	(In thousands)
As of December 31, 2018:	$	31,751	$	10,214	$	19,544	$	1,993	$	—

Purchase commitments mainly include minimum commitments for internet connection and marketing activities.

Purchase commitments as of December 31, 2018 were as follows:


			Less than One		One to		Three to		More than
Purchase commitments	Total		Year		Three Years		Five Years		Five Years
	(In thousands)
As of December 31, 2018:	$	568,852	$	564,339	$	4,394	$	119	$	—

2022 Notes represent the future maximum commitments relating to the principal amount and interests in connection with the issuance of $900 million in aggregate principal amount of 1.25% coupon interest convertible senior notes, which will mature on November 15, 2022.


			Less than One		One to		Three to		More than
2022 Notes	Total		Year		Three Years		Five Years		Five Years
	(In thousands)
As of December 31, 2018:	$	945,000	$	12,750	$	22,500	$	909,750	$	—

There are uncertainties regarding the legal basis of the Group’s ability to operate an Internet business in China. Although China has implemented a wide range of market-oriented economic reforms, the telecommunication, information and media industries remain highly regulated. Not only are such restrictions currently in place, the existing regulations are unclear as to which specific segments of these industries companies with foreign investors, including the Company, may operate. Therefore, the Group may be required to limit the scope of its operations in China, and this could have a material adverse effect on its financial position, results of operations and cash flows.

In June and August 2017, the Company and certain of its current and former directors and officers were named as defendants in two putative securities class actions filed in the United States District Court for the District of New Jersey, respectively. The actions - purportedly brought on behalf of a class of persons who allegedly suffered damages as a result of their trading in the Company’s ADSs between April 27 and June 22, 2017 or between April 28, 2016 and June 19, 2017, allege that the Company’s public filings contained material misstatements and omissions in violation of the U.S. federal securities laws. On September 28, 2017, the court entered an order appointing a lead plaintiff and consolidating the two cases. On November 27, 2017, the lead plaintiff filed a consolidated class action complaint. On January 26, 2018, the Company and one individual defendant filed a motion to dismiss the amended complaint. On June 7, 2018, the court granted the motion to dismiss the class action complaint in its entirety with prejudice.

There are no claims, lawsuits, investigations or proceedings, including unasserted claims that are probable to be assessed, that have in the recent past had, or to the Group’s knowledge, are reasonably possible to have, a material impact on the Group’s financial statements.

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2018
Subsequent Events
Subsequent Events	17. Subsequent Events The Group has performed an evaluation of subsequent events through the date of this report, which is the date the financial statements were issued, with no other material events nor transactions needing recognition or disclosure found.

Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2018

Significant Accounting Policies

Basis of presentation

Use of estimates

Revenue recognition

Impact of Adoption

The table below summarized the impact of adoption of the new revenue standard on the Group’s consolidated statement of comprehensive income for the year ended December 31, 2018.


	Year ended December 31, 2018
		Adjustments
			Barter
	ASC 605	VAT	Transaction	ASC 606
	($ In thousands)
Total revenues	1,703,644	(95,470)	110,344	1,718,518
Costs and expenses
Cost of revenues	373,118	(95,470)	—	277,648
Sales and marketing	418,004	—	109,420	527,424
Income from operations	608,340	—	924	609,264

Revenue disaggregated by revenue source for the years ended December 31, 2016, 2017 and 2018 consists of the following:


	Year Ended December 31,
	2016		2017		2018
	(In thousands)
Advertising and marketing revenues	$	570,982	$	996,745	$	1,499,180
Value-added services revenues		84,818		153,309		219,338
Total revenues	$	655,800	$	1,150,054	$	1,718,518

Practical Expedients and Exemptions

The Group generally expenses sales commissions when incurred because the amortization period is generally one year or less. These costs are recorded within sales and marketing expenses.

Advertising and marketing revenues

Value-added services revenues

Cost of revenues

Sales and Marketing Expenses

Product development expenses

Stock-based compensation

Taxation

Income taxes

Operating leases

Cash equivalents

Accounts receivable and allowances for doubtful accounts

Fair value measurements

Financial instruments

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

Level 3 applies to asset 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.

Long-term investments

Adoption of ASU 2016-01 and Its Implication

Business combination

Long-lived assets

Property and equipment

Goodwill

Intangible assets other than goodwill

Convertible debt

Deferred revenues

Non-controlling interests

Foreign currency

Net Income per share

Segment reporting

Concentration of risks

Recent accounting pronouncements

Operations and reorganization (Tables)

12 Months Ended

Dec. 31, 2018

Operations and reorganization

Schedule of the Company's major subsidiaries, major VIE and major VIE's subsidiary


			Percentage of
			Direct/
			Indirect
	Date of	Place of	Economic
Company	Incorporation	Incorporation	Interest
Major Subsidiaries
Weibo Hong Kong Limited (“Weibo HK”)	July 19, 2010	Hong Kong	100	%

Weibo Internet Technology (China) Co., Ltd. (“Weibo Technology” or "the WFOE”)	October 11, 2010	PRC	100	%

Major VIE and major VIE's subsidiary
Beijing Weimeng Technology Co., Ltd (“Weimeng")	August 9, 2010	PRC	100	%

Beijing Weibo Interactive Internet Technology Co., Ltd. (‘‘Weibo Interactive’’)	Acquired in May 2013	PRC	100	%

Schedule of total cost and expenses allocated from SINA


	Year Ended December 31,
	2016		2017		2018
	(In thousands)
Cost of revenues	$	11,022	$	13,699	$	16,824
Sales and marketing		1,271		9,732		11,558
Product development		9,094		11,312		11,688
General and administrative		4,316		6,393		7,264
	$	25,703	$	41,136	$	47,334

Schedule of assets, liabilities, results of operations and cash flows of the VIE and the VIE's subsidiaries taken as a whole.


	As of December 31,
	2017		2018
	(In thousands)
Cash, cash equivalents and short-term Investments	$	40,458	$	55,506
Accounts receivable		166,212		366,128
Property and equipment, net		146		449
Intangible assets		517		21,103
Goodwill		13,123		29,346
Prepayment for long-term investments		4,967		1,454
Long-term investments		74,935		275,819
Deferred tax assets		4,772		5,778
Amount due from SINA		4,677		31,787
Others		28,850		121,220
Total assets	$	338,657	$	908,590

Accounts payable	$	32,444	$	79,881
Accrued and other liabilities		114,239		181,188
Deferred revenues		54,651		65,531
Income tax payable		16,268		21,170
Amount due to the subsidiaries of the Group		57,639		440,563
Deferred tax liability		129		11,875
Total liabilities	$	275,370	$	800,208


	Year Ended December 31,
	2016		2017		2018
	(In thousands)
Net revenues	$	530,598	$	906,129	$	1,416,367
Net income (loss)	$	(21,758)	$	21,252	$	56,466


	Year Ended December 31,
	2016		2017		2018
	(In thousands)
Net cash provided by (used in) operating activities	$	(42,556)	$	(66,972)	$	46,738
Net cash used in investing activities	$	(28,577)	$	(34,720)	$	(331,243)
Net cash provided by (used in) financing activities	$	(1,148)	$	76,232	$	292,151
Net increase (decrease) in cash and cash equivalents	$	(72,281)	$	(25,460)	$	7,646

- 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, 2018

Significant Accounting Policies

Schedule of the impact of adoption of new revenue standard


	Year ended December 31, 2018
		Adjustments
			Barter
	ASC 605	VAT	Transaction	ASC 606
	($ In thousands)
Total revenues	1,703,644	(95,470)	110,344	1,718,518
Costs and expenses
Cost of revenues	373,118	(95,470)	—	277,648
Sales and marketing	418,004	—	109,420	527,424
Income from operations	608,340	—	924	609,264

Schedule of disaggregated revenue


	Year Ended December 31,
	2016		2017		2018
	(In thousands)
Advertising and marketing revenues	$	570,982	$	996,745	$	1,499,180
Value-added services revenues		84,818		153,309		219,338
Total revenues	$	655,800	$	1,150,054	$	1,718,518

Cash, Cash Equivalents and Short-term Investments (Tables)

12 Months Ended

Dec. 31, 2018

Cash, Cash Equivalents and Short-term Investments

Schedule of cash, cash equivalents and short-term investments


	As of December 31,
	2017		2018
	(In thousands)
Cash and cash equivalents:
Cash	$	1,000,953	$	1,234,596

Short-term investments:
Bank time deposits		791,730		591,269

Total cash, cash equivalents and short-term investments	$	1,792,683	$	1,825,865

Long-term Investments (Tables)

12 Months Ended

Dec. 31, 2018

Long-term Investments

Schedule of changes in the Group's long-term investments


	Cost Method/
	Equity Securities				Available-for-Sale
	Without Readily				Securities/
	Determinable Fair				Readily Determinable
	Values		Equity Method		Fair Values		Total
	(In thousands)
Balance at December 31, 2015	$	281,707	$	141	$	12,831	$	294,679
Investments made/transfers from prepayments		147,767		4,324		—		152,091
Loss from equity method investment		—		(130)		—		(130)
Disposal of investments		(6,010)		—		(5,000)		(11,010)
Impairment on investments		(31,586)		—		—		(31,586)
Unrealized loss		—		—		(2,557)		(2,557)
Currency translation adjustment		(1,548)		(6)		—		(1,554)

Balance at December 31, 2016	$	390,330	$	4,329	$	5,274	$	399,933
Investments made/transfers from prepayments		31,776		22,307		—		54,083
Gain from equity method investment		—		1,030		—		1,030
Dividend received from equity method investment		—		(267)		—		(267)
Impairment on investments		(4,747)		—		—		(4,747)
Unrealized loss		—		—		(995)		(995)
Currency translation adjustment		2,997		303		—		3,300

Balance at December 31, 2017	$	420,356	$	27,702	$	4,279	$	452,337
Investments made/transfers from prepayments		134,797		97,337		—		232,134
Gain from equity method investment		—		57		—		57
Dividend received from equity method investment		—		(657)		—		(657)
Disposal of investments		—		(1,623)		—		(1,623)
Impairment on investments		(23,557)		—		—		(23,557)
Fair value change through earnings (including adjustment of subsequent price changes)		42,877		—		(2,803)		40,074
Currency translation adjustment		(3,854)		(325)		—		(4,179)

Balance at December 31, 2018	$	570,619	$	122,491	$	1,476	$	694,586

Schedule of the total carrying value of the equity securities accounted for measurement alternative


Initial cost basis	$	555,153
Upward adjustments		42,877
Impairment		(23,557)
Foreign currency translation		(3,854)
Total carrying value at the end of the period	$	570,619

Schedule of the carrying amount and fair value of the marketable security


			Gross		Gross
	Cost		Unrealized		Unrealized		Fair
	Basis		Gains		Losses		Value
	(In thousands)
One marketable security	$	5,274	$	—	$	(995)	$	4,279
December 31, 2017	$	5,274	$	—	$	(995)	$	4,279
One marketable security	$	5,274	$	—	$	(3,798)	$	1,476
December 31, 2018	$	5,274	$	—	$	(3,798)	$	1,476

Acquisitions, Goodwill and Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2018

Acquisitions , Goodwill and Intangible Assets

Schedule of Consideration of acquisition of Yizhibo was allocated based on their fair value of the assets acquired and the liabilities assumed


	As of Acquisition Date
	(In thousands)
Consideration	$	50,000

Property and equipment, net		466
Identifiable intangible assets acquired		21,942
Other tangible assets		2,874
Liabilities assumed		(2,434)
Goodwill		27,152
Total	$	50,000

Schedule of the changes in the Group's goodwill by segment


	Advertising &		Value-added
	Marketing		services		Total
	(In thousands)
Balance as of December 31, 2016	$	—	$	10,266	$	10,266
New acquisition		—		2,318		2,318
Currency translation adjustment		—		836		836
Balance as of December 31, 2017	$	—	$	13,420	$	13,420
Acquisition of Yizhibo		27,152		—		27,152
Impairment		—		(10,554)		(10,554)
Currency translation adjustment		3		(675)		(672)
Balance as of December 31, 2018	$	27,155	$	2,191	$	29,346

Table summarizes the Group's intangible assets arising from acquisitions


	As of December 31, 2017						As of December 31, 2018
			Accumulated						Accumulated
	Cost		Amortization		Net		Cost		Amortization		Net
	(In thousand)						(In thousand)
Technology	$	2,533	$	(2,062)	$	471	$	8,978	$	(2,594)	$	6,384
Trademark and Domain name		—		—		—		5,623		(147)		5,476
Supplier-relationship		—		—		—		9,738		(495)		9,243
Others		2,460		(2,414)		46		2,326		(2,326)		—
Total	$	4,993	$	(4,476)	$	517	$	26,665	$	(5,562)	$	21,103

Schedule of estimated amortization expenses


Year Ended December 31,	(In thousands)
2019	$	3,364
2020		3,364
2021		3,364
2022		3,364
2023 and thereafter		7,647
Total expected amortization expense	$	21,103

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2018

Stock-Based Compensation

Schedule of the stock-based compensation


	Year Ended December 31,
	2016		2017		2018
	(In thousands)
Cost of revenues	$	2,616	$	3,716	$	3,522
Sales and marketing		5,357		8,264		6,837
Product development		15,076		21,879		21,187
General and administrative		13,853		14,178		9,465
	$	36,902	$	48,037	$	41,011

Summary of the number of shares available for issuance


		Shares Available
		(In thousands)
December 31, 2015		20,217
Addition		—
Granted*		(1,917)
Cancelled/expired/forfeited		578

December 31, 2016		18,878
Addition		—
Granted*		(736)
Cancelled/expired/forfeited		398

December 31, 2017		18,540
Addition		—
Granted*		(1,597)
Cancelled/expired/forfeited		350

December 31, 2018		17,293

Summary of option activities under the Company's stock option program


				Weighted Average
	Options	Weighted Average		Remaining	Aggregate
	Outstanding	Exercise Price		Contractual Life	Intrinsic Value
	(In thousands)			(In years)	(In thousands)
December 31, 2015	6,303	$	1.26	2.4	$	114,975
Granted	—	$	—
Exercised	(3,625)	$	1.10
Cancelled/expired/forfeited	(91)	$	3.37

December 31, 2016	2,587	$	1.41	1.6	$	101,403
Granted	—	$	—
Exercised	(2,122)	$	1.04
Cancelled/expired/forfeited	(28)	$	0.68

December 31, 2017	437	$	3.24	2.0	$	43,800
Granted	—	$	—
Exercised	(248)	$	3.14
Cancelled/expired/forfeited	(5)	$	1.16

December 31, 2018	184	$	3.45	1.5	$	10,089

Vested and expected to vest as of December 31, 2017	437	$	3.24	2.0	$	43,800
Exercisable as of December 31, 2017	437	$	3.24	2.0	$	43,800

Vested and expected to vest as of December 31, 2018	184	$	3.45	1.5	$	10,089
Exercisable as of December 31, 2018	184	$	3.45	1.5	$	10,089

Schedule of stock options outstanding


		Weighted			Weighted		Weighted Average
	Options	Average		Options	Average		Remaining
Range of Exercise Prices	Outstanding	Exercise Price		Exercisable	Exercise Price		Contractual Life
	(In thousands)			(In thousands)			(In years)
As of December 31, 2017
$ 0.96 - $1.80	31	$	0.97	31	$	0.97	0.2
$ 3.25 - $3.36	179	$	3.33	179	$	3.33	1.4
$ 3.43 - $3.50	227	$	3.48	227	$	3.48	2.6
	437	$	3.24	437	$	3.24	2.0

As of December 31, 2018
$ 3.25 - $3.36	32	$	3.30	32	$	3.30	0.8
$ 3.43 - $3.50	152	$	3.48	152	$	3.48	1.7
	184	$	3.45	184	$	3.45	1.5

Performance-Based Restricted Share Units

Stock-Based Compensation

Summary of restricted share unit activities


		Weighted-Average
		Grant Date
	Shares Granted	Fair Value
	(In thousands)
December 31, 2015	—	$	—
Awarded	111	$	27.00
Cancelled	(3)	$	27.00

December 31, 2016	108	$	27.00
Awarded	155	$	50.45
Vested	(102)	$	27.00
Cancelled	(32)	$	46.42

December 31, 2017	129	$	50.32
Awarded	191	$	86.63
Vested	(126)	$	50.32
Cancelled	(190)	$	86.90

December 31, 2018	4	$	87.14

Service-Based Restricted share Units

Stock-Based Compensation

Summary of restricted share unit activities


		Weighted-
		Average
	Shares	Grant Date
	Granted	Fair Value
	(In
	thousands)
December 31, 2015	6,501	$	13.98
Awarded	1,806	$	24.94
Vested	(2,274)	$	14.73
Cancelled	(575)	$	14.58

December 31, 2016	5,458	$	17.23
Awarded	581	$	62.87
Vested	(2,406)	$	17.01
Cancelled	(366)	$	17.72

December 31, 2017	3,267	$	25.45
Awarded	1,406	$	68.18
Vested	(1,757)	$	21.59
Cancelled	(160)	$	44.00

December 31, 2018	2,756		48.62

Other Balance Sheet Components (Tables)

12 Months Ended

Dec. 31, 2018

Other Balance Sheet Components

Schedule of other balance sheet components


	As of December 31,
	2016	2017		2018
	(In thousands)
Accounts receivable, net:
Due from third parties	—	$	105,686	$	201,835
Due from Alibaba	—		42,832		48,222
Due from other related parties	—		29,696		131,465

Total gross amount	—	$	178,214	$	381,522
Allowance for doubtful accounts:
Balance at the beginning of the year	(1,375)		(6,529)		(8,114)
Reversal (additional provision) charged to expenses, net	(7,787)		(5,478)		(6,226)
Write-off	2,633		3,893		1,911

Balance at the end of the year	(6,529)		(8,114)		(12,429)
	—	$	170,100	$	369,093

Prepaid expenses and other current assets:
Rental and other deposits	—	$	2,233	$	684
Deductable value-added taxes	—		—		4,539
Prepayment for investments	—		20,881		106,256
Advertising prepayment	—		3,959		4,575
Prepayment to outsourced service providers	—		5,369		4,730
Amounts deposited by users*	—		25,277		30,631
Content fees	—		7,393		11,021
Others	—		4,121		6,385
	—	$	69,233	$	168,821

Property and equipment, net:
Computers and equipment	—	$	113,558	$	124,241
Leasehold improvements	—		4,321		5,008
Furniture and fixtures	—		1,241		1,677
Others	—		2,574		2,696

Property and equipment, gross	—		121,694		133,622
Less: Accumulated depreciation	—		(87,901)		(87,999)
	—	$	33,793	$	45,623

Accrued and other liabilities**:
Payroll and welfare	—	$	57,848	$	56,349
Marketing expenses	—		53,380		49,998
Payroll withholding taxes	—		3,547		3,547
Sales rebates	—		60,663		95,121
Professional fees	—		6,170		8,249
VAT and other tax payable	—		51,563		48,651
Payable to other service providers	—		362		1,266
Amounts due to users*	—		25,277		30,631
Unpaid consideration for acquisition	—		—		10,000
Others	—		9,805		13,625
	—	$	268,615	$	317,437

** Include amounts due to third parties, employees, related parties (see Note 9) and Weibo wallet users.

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Income Taxes

Schedule of income before income taxes


	Year Ended December 31,
	2016			2017			2018
	(In thousands, except percentage)
Income before income tax expenses	$	109,980		$	417,111		$	668,842
Add: loss from non-China operations	$	60,193		$	52,261		$	43,266
Income from China operations	$	170,173		$	469,372		$	712,108
Income tax expense applicable to China operations	$	4,316		$	66,746		$	96,222
Effective tax rate for China operations		2.5	%		14.2	%		13.5	%

Schedule of current and deferred portion of income tax expenses


	Years Ended December 31,
	2016		2017		2018
		(In thousands)
Deferred tax (benefits)/provisions	$	(4,630)	$	(1,503)	$	4,438
Current income tax expenses		8,946		68,249		91,784

Income tax expenses	$	4,316	$	66,746	$	96,222

Schedule of reconciliation between the statutory EIT rate and the effective tax rate for China operations


	Year Ended December 31,
	2016		2017		2018
Statutory EIT rate	25.0	%	25.0	%	25.0	%
Effect on tax holiday and preferential tax treatment(1)	(29.6)	%	(11.6)	%	(12.1)	%
Permanent differences	1.2	%	0.2	%	0.6	%
Change in valuation allowance	5.9	%	0.6	%	0.0	%

Effective tax rate for China operations	2.5	%	14.2	%	13.5	%

(1)

Included the impact of Weibo Technology’s preferential tax treatment of “key software enterprise” status of 2017 in 2018.

Schedule of significant components of deferred tax assets and liabilities for China operations


	As of December 31,
	2017		2018
	(In thousands)
Deferred tax assets:
Net operating loss carry forwards	$	10,280	$	4,180
Less: valuation allowance		(10,280)		(4,180)
Depreciation, accounts receivable, accrued and other liabilities		19,931		25,327
Less: valuation allowance		(11,629)		(13,419)

Net deferred tax assets (included in other assets)	$	8,302	$	11,908

Deferred tax liabilities:
Acquired intangible assets	$	129	$	2,310
Depreciation		527		702
Investment gain		—		9,565
Others		1,224		—

Total deferred tax liabilities	$	1,880	$	12,577

Related Party Transactions (Tables)

12 Months Ended

Dec. 31, 2018

Related Party Transactions

Schedule of significant related parties and their relationships with the Company


Company Name		Relationship with the Company
SINA		Parent and affiliates under common control.

Alibaba		Strategic partner and significant shareholder of the Company.

Schedule of significant related party transactions with the Company


	Year Ended December 31,
	2016		2017		2018
	(In thousands)
Transactions with SINA
Revenue billed through/for service provided to SINA(1)	$	39,285	$	64,093	$	90,645
Costs and expenses allocated from SINA(2)	$	25,703	$	41,136	$	47,334
Interest income on matching loan to SINA	$	—	$	1,735	$	—
Interest expense on matching loan from SINA	$	—	$	1,537	$	—
Interest income on loans to SINA		—		—		2,425

(1)

(2)


	Year Ended December 31,
	2016		2017		2018
	(In thousands)
Transactions with Alibaba
Advertising and marketing services provided to Alibaba	$	57,908	$	84,688	$	117,696
Services provided by Alibaba	$	13,988	$	32,734	$	47,642


	As of December 31,
	2017		2018
		(In thousands)
Amount due from SINA(3)	$	16,356	$	105,319
Accounts receivable due from Alibaba	$	42,832	$	48,222

Net Income per Share (Tables)

12 Months Ended

Dec. 31, 2018

Net Income per Share

Schedule of basic and diluted net income per share


	Year Ended December 31,
	2016		2017		2018
	(In thousands, except per share data)
Basic net income per share calculation:
Numerator:
Net income attributable to Weibo	$	108,027	$	352,590	$	571,823
Denominator:
Weighted average ordinary shares outstanding		214,745		220,555		223,751
Basic net income per share attributable to Weibo	$	0.50	$	1.60	$	2.56

Diluted net income per share calculation:
Numerator:
Net income attributable to Weibo	$	108,027	$	352,590	$	571,823
Add: Effect on interest expenses and amortized issuance cost of convertible debt		—		—		15,390
Net income attributable for calculating diluted net income per share		108,027		352,590		587,213
Denominator:
Weighted average ordinary shares outstanding		214,745		220,555		223,751
Weighted average ordinary shares equivalents:
Effects of dilutive securities
Stock options		4,334		1,213		283
Unvested restricted share units		3,780		3,595		1,896
Convertible debt		—		—		6,753
Shares used in computing diluted net income per share attributable to Weibo		222,859		225,363		232,683
Diluted net income per share attributable to Weibo	$	0.48	$	1.56	$	2.52

Segment Information (Tables)

12 Months Ended

Dec. 31, 2018

Segment Information

Summary of the Group's revenues


Revenues	Advertising & Marketing		Value-added services		Total
	(In thousand)
Year ended December 31, 2016	$	570,982	$	84,818	$	655,800

Year ended December 31, 2017	$	996,745	$	153,309	$	1,150,054

Year ended December 31, 2018	$	1,499,180	$	219,338	$	1,718,518

Fair Value Measurement (Tables)

12 Months Ended

Dec. 31, 2018

Fair Value Measurement

Schedule of assets measured at fair value on a recurring basis, the respective fair value and the classification by level of input within the fair value hierarchy


	Fair Value Measurements
	(in thousands)
			Quoted Prices in
			Active Market		Significant Other		Significant
			for Identical Assets		Observable Inputs		Unobservable Inputs
	Total		(Level 1)		(Level 2)		(Level 3)
As of December 31, 2017:
Bank time deposits*	$	791,730	$	—	$	791,730	$	—
Available-for-sale equity securities**		4,279		4,279		—		—
Total	$	796,009	$	4,279	$	791,730	$	—

As of December 31, 2018:
Bank time deposits*	$	591,269	$	—	$	591,269	$	—
Equity securities with readily determinable market value **		1,476		1,476		—		—
Total	$	592,745	$	1,476	$	591,269	$	—

* Included in short-term investments on the Group’s consolidated balance sheets.

** Included in long-term investments on the Group’s consolidated balance sheets.

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2018

Commitments and Contingencies

Schedule of future minimum lease payments


			Less than One		One to		Three to		More than
Operating lease commitments	Total		Year		Three Years		Five Years		Five Years
	(In thousands)
As of December 31, 2018:	$	31,751	$	10,214	$	19,544	$	1,993	$	—

Schedule of purchase commitments


			Less than One		One to		Three to		More than
Purchase commitments	Total		Year		Three Years		Five Years		Five Years
	(In thousands)
As of December 31, 2018:	$	568,852	$	564,339	$	4,394	$	119	$	—

Schedule of 2022 Notes maturity


			Less than One		One to		Three to		More than
2022 Notes	Total		Year		Three Years		Five Years		Five Years
	(In thousands)
As of December 31, 2018:	$	945,000	$	12,750	$	22,500	$	909,750	$	—

Operations and reorganization - Narrative Information (Details) $ in Millions	1 Months Ended	12 Months Ended
	Apr. 30, 2014 USD ($)	Dec. 31, 2018 Vote
Class A ordinary shares
Operations and reorganization
Number of votes each share is entitled to		1
Number of Class A shares converted from Class B shares		1
Class B ordinary shares
Operations and reorganization
Number of votes each share is entitled to		3
IPO \| Class A ordinary shares
Operations and reorganization
Proceeds from IPO \| $	$ 306.5
Weimeng
Operations and reorganization
Percentage of Direct/Indirect Economic Interest in VIEs		100.00%
Weibo Interactive
Operations and reorganization
Percentage of Direct/Indirect Economic Interest in VIEs		100.00%
Weibo HK
Operations and reorganization
Percentage of Direct/Indirect Economic Interest		100.00%
Weibo Technology
Operations and reorganization
Percentage of Direct/Indirect Economic Interest		100.00%

Operations and reorganization - Assets, Liabilities, Statement of Operations and Cash Flows (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Oct. 01, 2018	Dec. 31, 2015
Operations and reorganization
Allocated expenses from SINA	$ 47,334,000	$ 41,136,000	$ 25,703,000
Interest-free loans to the VIE's shareholders	82,100,000	86,900,000
Aggregate accumulated income (loss)	23,200,000	(33,300,000)
Assets and liabilities of the VIEs and their subsidiaries
Cash, cash equivalents and short-term Investments	1,825,865,000	1,792,683,000
Property and equipment, net	45,623,000	33,793,000
Intangible assets	21,103,000	517,000
Goodwill	29,346,000	13,420,000	10,266,000	$ 27,152,000
Long-term investments	694,586,000	452,337,000	399,933,000		$ 294,679,000
Accounts payable	123,730,000	64,043,000
Accrued and other liabilities	317,437,000	268,615,000
Deferred revenues	99,994,000	81,311,000
Income tax payable	88,683,000	70,907,000
Deferred tax liability	12,577,000	1,880,000
Results of operations of the VIEs and their subsidiaries
Net revenues	1,718,518,000	1,150,054,000	655,800,000
Net income (loss)	571,823,000	352,590,000	108,027,000
Cash flows of the VIE and its subsidiary
Net cash provided by (used in) operating activities	488,007,000	539,151,000	236,244,000
Net cash used in investing activities	(254,032,000)	(815,422,000)	(96,745,000)
Net cash provided by (used in) financing activities	(1,415,000)	883,578,000	3,035,000
Assets, except for registered capital of VIEs, that can only be used to settle obligations of the respective VIEs	0	0
Registered capital and non-distributable reserve funds of VIE and its subsidiaries	$ 144,100,000	137,300,000
Term of loan agreements	10 years
Service fees revenue charged to VIE	$ 842,600,000	618,100,000	335,600,000
Term of trademark license agreements	1 year
Consolidated VIEs
Operations and reorganization
Allocated expenses from SINA	$ 25,600,000	21,400,000	12,300,000
Assets and liabilities of the VIEs and their subsidiaries
Cash, cash equivalents and short-term Investments	55,506,000	40,458,000
Accounts receivable	366,128,000	166,212,000
Property and equipment, net	449,000	146,000
Intangible assets	21,103,000	517,000
Goodwill	29,346,000	13,123,000
Prepayment for long-term investments	1,454,000	4,967,000
Long-term investments	275,819,000	74,935,000
Deferred tax assets	5,778,000	4,772,000
Amount due from SINA	31,787,000	4,677,000
Others	121,220,000	28,850,000
Total assets	908,590,000	338,657,000
Accounts payable	79,881,000	32,444,000
Accrued and other liabilities	181,188,000	114,239,000
Deferred revenues	65,531,000	54,651,000
Income tax payable	21,170,000	16,268,000
Amount due to the subsidiaries of the Group	440,563,000	57,639,000
Deferred tax liability	11,875,000	129,000
Total liabilities	800,208,000	275,370,000
Results of operations of the VIEs and their subsidiaries
Net revenues	1,416,367,000	906,129,000	530,598,000
Net income (loss)	56,466,000	21,252,000	(21,758,000)
Cash flows of the VIE and its subsidiary
Net cash provided by (used in) operating activities	46,738,000	(66,972,000)	(42,556,000)
Net cash used in investing activities	(331,243,000)	(34,720,000)	(28,577,000)
Net cash provided by (used in) financing activities	292,151,000	76,232,000	(1,148,000)
Net increase (decrease) in cash and cash equivalents	7,646,000	(25,460,000)	(72,281,000)
Cost of revenues
Operations and reorganization
Allocated expenses from SINA	16,824,000	13,699,000	11,022,000
Sales and marketing
Operations and reorganization
Allocated expenses from SINA	11,558,000	9,732,000	1,271,000
Product development
Operations and reorganization
Allocated expenses from SINA	11,688,000	11,312,000	9,094,000
General and administrative
Operations and reorganization
Allocated expenses from SINA	$ 7,264,000	$ 6,393,000	$ 4,316,000

Significant Accounting Policies (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 01, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues:
Deferred revenues		$ 99,994	$ 81,311
Other current assets		6,385	4,121
Revenues		1,718,518	1,150,054	$ 655,800
Cost of revenues		277,648	231,255	171,231
Sales and marketing		527,424	275,537	148,283
Income from operations		609,264	407,554	140,980
Revenue recognized as deferred revenue		$ 67,200
Costs and Expenses
VAT and surcharges (as a percent)		6.70%
Sales and Marketing Expenses
Advertising and promotional expenses		$ 428,800	200,600	92,200
Operating leases
Allocated rental expenses from SINA		47,334	41,136	25,703
Long-term investments
Available-for-sale of marketable securities	$ 0
Unrealized loss on accumulated other comprehensive income to retained earnings	1,000		(995)	(2,557)
Impairment charge		$ 23,557	4,747	31,586
Stock options
Stock-based compensation
Vesting period		4 years
Service-Based Restricted share Units
Stock-based compensation
Vesting period		4 years
Rental expense
Operating leases
Allocated rental expenses from SINA		$ 4,900	4,500	3,900
Impact of adoption of new revenue guidance
Revenues:
Cumulative-effect adjustment on the retained earnings	$ (600)
Deferred revenues		2,100
Other current assets		600
Revenues		1,718,518
Cost of revenues		277,648
Sales and marketing		527,424
Income from operations		609,264
Impact of adoption of new revenue guidance \| ASC 605
Revenues:
Revenues		1,703,644
Cost of revenues		373,118
Sales and marketing		418,004
Income from operations		608,340
Impact of adoption of new revenue guidance \| VAT
Revenues:
Revenues		(95,470)
Cost of revenues		(95,470)
Impact of adoption of new revenue guidance \| Barter Transaction
Revenues:
Revenues		110,344
Sales and marketing		109,420
Income from operations		$ 924
Maximum
Operating leases
Lease period		5 years 6 months
Advertising & Marketing
Revenues:
Revenues		$ 1,499,180	996,745	570,982
Costs and Expenses
Cultural business construction fees (as a percent)		3.00%
Taxes on advertising and marketing revenues		$ 52,900	90,600	49,900
Advertising & Marketing \| Maximum
Revenues:
Period over social display ad arrangements allow customers to place advertisements on particular areas of the Group's platform in particular formats		3 months
Value-added services
Revenues:
Revenues		$ 219,338	$ 153,309	$ 84,818
Game-related service
Maximum period for recognition of revenues after purchase of in-game credits		1 month

Significant Accounting Policies - Property and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property and equipment
Depreciation expenses	$ 18.5	$ 14.7	$ 13.3
Computers and equipment \| Minimum
Property and equipment
Estimated useful lives of assets	3 years
Computers and equipment \| Maximum
Property and equipment
Estimated useful lives of assets	4 years
Furniture and fixtures
Property and equipment
Estimated useful lives of assets	5 years

Significant Accounting Policies - Intangible Assets Other Than Goodwill, Foreign Currency and Segment Reporting (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) segment	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Foreign currency
Currency translation adjustments \| $	$ (60,273)	$ 37,822	$ (18,898)
Segment reporting
Number of principal business segments \| segment	2
Minimum
Intangible assets other than goodwill
Estimated useful lives of intangible assets	5 years
Maximum
Intangible assets other than goodwill
Estimated useful lives of intangible assets	10 years

Significant Accounting Policies - Concentration of Risks (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) customer Agency	Dec. 31, 2017 USD ($) customer Agency	Dec. 31, 2016 Agency
Concentration of risks
Cash, cash equivalents and short-term investments	$ 1,825,865	$ 1,792,683
Current liabilities denominated in RMB	629,844	484,876
Cash, cash equivalents and short-term investments \| Concentration of credit risk \| China
Concentration of risks
Cash, cash equivalents and short-term investments	$ 1,730,000	1,790,000
Maximum term of original maturity of time deposits	12 months
Cash, cash equivalents and short-term investments \| Concentration of foreign currency risks \| RMB
Concentration of risks
Cash, cash equivalents and short-term investments	$ 950,800	$ 871,200
Percentage of benchmark derived from specified source	52.00%	49.00%
Consolidated net revenues benchmark \| Customer concentration risk \| Alibaba
Concentration of risks
Percentage of benchmark derived from specified source	7.00%	7.00%	9.00%
Consolidated net accounts receivables benchmark \| Concentration of credit risk \| Alibaba
Concentration of risks
Percentage of benchmark derived from specified source	13.00%	25.00%
Consolidated net accounts receivables benchmark \| Concentration of credit risk \| Customer 1
Concentration of risks
Percentage of benchmark derived from specified source	6.00%	10.00%
Number of customers \| customer	1	1
Consolidated net accounts receivables benchmark \| Concentration of credit risk \| Customer 2
Concentration of risks
Percentage of benchmark derived from specified source	22.00%	6.00%
Number of customers \| customer	1	1
Consolidated net accounts receivables benchmark \| Concentration of foreign currency risks \| RMB
Concentration of risks
Accounts receivable denominated in RMB	$ 368,800	$ 170,100
Current liabilities \| Concentration of foreign currency risks \| RMB
Concentration of risks
Current liabilities denominated in RMB	$ 620,400	$ 475,600
Percentage of benchmark derived from specified source	99.00%	98.00%
Advertising & Marketing \| Consolidated net revenues benchmark \| Customer concentration risk \| Top 10 advertising agencies \| China
Concentration of risks
Number of advertising agencies \| Agency	10	10	10
Percentage of benchmark derived from specified source	26.00%	23.00%	22.00%

Significant Accounting Policies - Recent accounting pronouncements (Details) - Scenario forecast - ASU 2018-11 $ in Millions	Mar. 31, 2019 USD ($)
Minimum
Recent accounting pronouncements
Cumulative-effect adjustment	$ 10.0
Maximum
Recent accounting pronouncements
Cumulative-effect adjustment	$ 12.0

Cash, Cash Equivalents and Short-term Investments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash and cash equivalents:
Cash	$ 1,234,596	$ 1,000,953	$ 364,766	$ 237,440
Short-term investments:
Bank time deposits	591,269	791,730
Total cash, cash equivalents and short-term investments	1,825,865	1,792,683
Interest income	$ 58,000	$ 19,500	$ 7,600

Long-term Investments (Details) $ in Thousands	12 Months Ended
Long-term Investments (Details) $ in Thousands	Dec. 31, 2018 USD ($) item	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2014 USD ($)
Long-term investments
Balance at the beginning of the year	$ 452,337	$ 399,933	$ 294,679
Investments made/transfers from prepayments	232,134	54,083	152,091
Income (loss) from equity method investments	57	1,030	(130)
Disposal of investments	(1,623)		(11,010)
Dividend received from equity method investment	(657)	(267)
Impairment on investments	(23,557)	(4,747)	(31,586)
Unrealized loss	2,800	(995)	(2,557)
Fair value change through earnings (including adjustment of subsequent price changes)	40,074
Currency translation adjustment	(4,179)	3,300	(1,554)
Balance at the end of year	694,586	452,337	399,933
Total carrying value of the equity securities
Initial cost basis	555,153
Upward adjustments	42,877
Impairment	(23,557)
Foreign currency translation	(3,854)
Total carrying value at the end of the period	570,619
Gain on investment	$ 42,900
Number of investment fund \| item	2
Impairment charge	$ 23,600
Carrying amount and fair value of the marketable security
Cost Basis		5,274
Gross Unrealized Losses		(995)
Fair value		4,279
Cost Basis	5,274
Gross Unrealized Losses	(3,798)
Fair Value	1,476
Investment related impairment	24,074	4,747	40,161
Write-offs of prepayments	500		3,800
Private high tech companies
Long-term investments
Investments made/transfers from prepayments	134,800
Limited partnerships
Long-term investments
Investments made/transfers from prepayments	97,300
Investing fund one
Long-term investments
Investments made/transfers from prepayments	48,000
Investing fund two
Long-term investments
Investments made/transfers from prepayments	45,000
One marketable security
Carrying amount and fair value of the marketable security
Cost Basis		5,274
Gross Unrealized Losses		(995)
Fair value		4,279
Cost Basis	5,274
Gross Unrealized Losses	(3,798)
Fair Value	1,476
Online-to-offline business
Long-term investments
Impairment on investments			(19,000)
Employment-oriented social company
Long-term investments
Impairment on investments			(10,500)
Online-reading business
Carrying amount and fair value of the marketable security
Investment related impairment	11,900
A Company operating in game business
Carrying amount and fair value of the marketable security
Investment related impairment	9,700
Cost Method /Equity Securities Without Readily Determinable Fair Values
Long-term investments
Balance at the beginning of the year	420,356	390,330	281,707
Investments made/transfers from prepayments	134,797	31,776	147,767
Disposal of investments			(6,010)
Impairment on investments	(23,557)	(4,747)	(31,586)
Fair value change through earnings (including adjustment of subsequent price changes)	42,877
Currency translation adjustment	(3,854)	2,997	(1,548)
Balance at the end of year	570,619	420,356	390,330
Equity Method
Long-term investments
Balance at the beginning of the year	27,702	4,329	141
Investments made/transfers from prepayments	97,337	22,307	4,324
Income (loss) from equity method investments	57	1,030	(130)
Disposal of investments	(1,623)
Dividend received from equity method investment	(657)	(267)
Currency translation adjustment	(325)	303	(6)
Balance at the end of year	122,491	27,702	4,329
Available-for-Sale Securities/Readily Determinable Fair Values
Long-term investments
Balance at the beginning of the year	4,279	5,274	12,831
Investments made/transfers from prepayments				$ 15,100
Disposal of investments			(5,000)
Unrealized loss		(995)	(2,557)
Fair value change through earnings (including adjustment of subsequent price changes)	(2,803)
Balance at the end of year	$ 1,476	$ 4,279	5,274
Total carrying value of the equity securities
Impairment charged to net income			$ 4,800

Acquisitions, Goodwill and Intangible Assets - Allocation of Consideration (Details) $ in Thousands		12 Months Ended
	Oct. 01, 2018 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($) item	Dec. 31, 2016 USD ($) item
Acquisitions, Goodwill and Intangible Assets
Number of immaterial acquisitions \| item			1
Number of new acquisitions \| item				0
Business combination allocated based on fair value of the assets and the liabilities
Consideration	$ 50,000
Property and equipment, net	466
Identifiable intangible assets acquired	21,942	$ 21,100
Other tangible assets	2,874
Liabilities assumed	(2,434)
Goodwill	27,152	29,346	$ 13,420	$ 10,266
Total	50,000
Yizhibo
Acquisitions, Goodwill and Intangible Assets
Cash consideration	40,000
Final consideration scheduled to be paid in 2019	10,000
Revenue increase due to acquisition		$ 28,000
Business combination allocated based on fair value of the assets and the liabilities
Consideration	$ 50,000
Yizhibo \| Supplier-relationship
Acquisitions, Goodwill and Intangible Assets
Estimated useful lives of intangible assets	5 years
Business combination allocated based on fair value of the assets and the liabilities
Identifiable intangible assets acquired	$ 9,700
Yizhibo \| Core Technology
Acquisitions, Goodwill and Intangible Assets
Estimated useful lives of intangible assets	8 years
Business combination allocated based on fair value of the assets and the liabilities
Identifiable intangible assets acquired	$ 6,600
Yizhibo \| Trademark and Domain name
Acquisitions, Goodwill and Intangible Assets
Estimated useful lives of intangible assets	10 years
Business combination allocated based on fair value of the assets and the liabilities
Identifiable intangible assets acquired	$ 5,600

Acquisitions, Goodwill and Intangible Assets - Changes in the Group's Goodwill (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Changes in the Group's goodwill by segment
Balance at the beginning of the year	$ 13,420,000	$ 10,266,000
Acquisition		2,318,000
Impairment	(10,554,000)
Currency translation adjustment	(672,000)	836,000
Balance at the end of the year	29,346,000	13,420,000	$ 10,266,000
Impairment of goodwill	10,600,000	0	0
Advertising & Marketing
Changes in the Group's goodwill by segment
Currency translation adjustment	3,000
Balance at the end of the year	27,155,000
Value-added services
Changes in the Group's goodwill by segment
Balance at the beginning of the year	13,420,000	10,266,000
Acquisition		2,318,000
Impairment	(10,554,000)
Currency translation adjustment	(675,000)	836,000
Balance at the end of the year	2,191,000	$ 13,420,000	$ 10,266,000
Yizhibo
Changes in the Group's goodwill by segment
Acquisition	27,152,000
Yizhibo \| Advertising & Marketing
Changes in the Group's goodwill by segment
Acquisition	$ 27,152,000

Acquisitions, Goodwill and Intangible Assets - Intangible assets arising from acquisitions (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Acquired finite-lived intangible assets
Cost	$ 26,665	$ 4,993
Accumulated Amortization	(5,562)	(4,476)
Net	21,103	517
Technology
Acquired finite-lived intangible assets
Cost	8,978	2,533
Accumulated Amortization	(2,594)	(2,062)
Net	6,384	471
Trademark and Domain name
Acquired finite-lived intangible assets
Cost	5,623
Accumulated Amortization	(147)
Net	5,476
Supplier-relationship
Acquired finite-lived intangible assets
Cost	9,738
Accumulated Amortization	(495)
Net	9,243
Others
Acquired finite-lived intangible assets
Cost	2,326	2,460
Accumulated Amortization	$ (2,326)	(2,414)
Net		$ 46

Acquisitions, Goodwill and Intangible Assets - Future Amortization Expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Acquisitions , Goodwill and Intangible Assets
Intangible assets, net	$ 21,103	$ 517
Amortization expense	1,300	600	$ 700
Future estimated amortization expenses
2019	3,364
2020	3,364
2021	3,364
2022	3,364
2023 and thereafter	7,647
Total expected amortization expense	$ 21,103	$ 517

Stock-Based Compensation - Incentive Plan Details (Details) - shares		1 Months Ended
	Jan. 01, 2015	Mar. 31, 2014	Aug. 31, 2010
2010 Plan
Stock-Based Compensation
Term of share incentive plan			10 years
Ordinary shares reserved for issuance			35,000,000
Amount that maximum number of ordinary shares available for issuance is reduced for every share issued pursuant to share option or share appreciation right			1
Amount that maximum number of ordinary shares available for issuance is reduced for every share issued as restricted shares or pursuant to restricted share units			1.75
2014 Plan
Stock-Based Compensation
Term of share incentive plan	10 years
Ordinary shares reserved for issuance		4,600,000
Number of additional shares for the plan		1,000,000
One-time percentage increase on January 1, 2015 for maximum aggregate number of shares which may be issued (as a percent)	10.00%

Stock-Based Compensation - Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Stock-based compensation
Stock-based compensation expense	$ 41,011	$ 48,037	$ 36,902
Amortization period	4 years
Cost of revenues
Stock-based compensation
Stock-based compensation expense	$ 3,522	3,716	2,616
Sales and marketing
Stock-based compensation
Stock-based compensation expense	6,837	8,264	5,357
Product development
Stock-based compensation
Stock-based compensation expense	21,187	21,879	15,076
General and administrative
Stock-based compensation
Stock-based compensation expense	$ 9,465	$ 14,178	$ 13,853

Stock-Based Compensation - Number of Shares Available for Issuance (Details) - USD ($)
$ / shares in Units, shares in Thousands

1 Months Ended

12 Months Ended

Mar. 31, 2014

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Number of shares available for issuance

Outstanding number of shares available for issuance at the beginning of the year (in shares)

18,540

18,878

20,217

Granted (in shares)

^[1]

(1,597)

(736)

(1,917)

Cancelled/expired/forfeited (in shares)

350

398

578

Outstanding number of shares available for issuance at the end of the year (in shares)

17,293

18,540

18,878

20,217

Aggregate Intrinsic Value

Fair value per ordinary share (in dollars per share)

$ 58.43

$ 103.46

$ 40.60

Cash received from the exercise of stock option

$ 781,000

$ 2,285,000

$ 4,183,000

2014 Plan

Number of shares available for issuance

Addition (in shares)

1,000

Stock options

Options Outstanding

Outstanding at the beginning of the year (in shares)

437

2,587

6,303

Exercised (in shares)

(248)

(2,122)

(3,625)

Cancelled/expired/forfeited (in shares)

(5)

(28)

(91)

Outstanding at the end of the year (in shares)

184

437

2,587

6,303

Vested and expected to vest at the end of the year (in shares)

184

437

Exercisable at the end of the year (in shares)

184

437

Weighted Average Exercise Price

Outstanding at the beginning of the year (in dollars per share)

$ 3.24

$ 1.41

$ 1.26

Exercised (in dollars per share)

3.14

1.04

1.10

Cancelled/expired/forfeited (in dollars per share)

1.16

0.68

3.37

Outstanding at the end of the year (in dollars per share)

3.45

3.24

$ 1.41

$ 1.26

Vested and expected to vest at the end of the year (in dollars per share)

3.45

3.24

Exercisable at the end of the year (in dollars per share)

$ 3.45

$ 3.24

Weighted Average Remaining Contractual Life (In years)

Outstanding at the end of the year

1 year 6 months

2 years

1 year 7 months 6 days

2 years 4 months 24 days

Vested and expected to vest at the end of the year

1 year 6 months

2 years

Exercisable at the end of the year

1 year 6 months

2 years

Aggregate Intrinsic Value

Outstanding at the end of the year

$ 10,089,000

$ 43,800,000

$ 101,403,000

$ 114,975,000

Vested and expected to vest at the end of the year

10,089,000

43,800,000

Exercisable at the end of the year

10,089,000

43,800,000

Total intrinsic value of options exercised

25,600,000

135,200,000

129,300,000

Cash received from the exercise of stock option

800,000

$ 2,300,000

$ 4,200,000

Unrecognized compensation cost

$ 0

Stock options | 2014 Plan

Number of shares available for issuance

Granted (in shares)

Restricted share units | 2014 Plan

Number of shares available for issuance

Restricted shares units granted (in shares)

1,600

700

1,900

[1]	For the years ended December 31, 2016, 2017 and 2018, 1.9 million, 0.7 million and 1.6 million restricted share units were granted under the 2014 Plan, respectively. No options were granted for the three-year period ended December 31, 2018.

Stock-Based Compensation - Summary of Option Activities (Details) - Stock options - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Range of Exercise Prices
Options Outstanding (in shares)	184	437
Weighted Average Exercise Price (in dollars per share)	$ 3.45	$ 3.24
Options Exercisable (in shares)	184	437
Weighted Average Exercise Price (in dollars per share)	$ 3.45	$ 3.24
Weighted Average Remaining Contractual Life (In years)	1 year 6 months	2 years
$0.96 - $1.80
Range of Exercise Prices
Exercise prices, outstanding stock option awards, low end of range (in dollars per share)		$ 0.96
Exercise prices, outstanding stock option awards, high end of range (in dollars per share)		$ 1.80
Options Outstanding (in shares)		31
Weighted Average Exercise Price (in dollars per share)		$ 0.97
Options Exercisable (in shares)		31
Weighted Average Exercise Price (in dollars per share)		$ 0.97
Weighted Average Remaining Contractual Life (In years)		2 months 12 days
$3.25 - $3.36
Range of Exercise Prices
Exercise prices, outstanding stock option awards, low end of range (in dollars per share)	$ 3.25	$ 3.25
Exercise prices, outstanding stock option awards, high end of range (in dollars per share)	$ 3.36	$ 3.36
Options Outstanding (in shares)	32	179
Weighted Average Exercise Price (in dollars per share)	$ 3.30	$ 3.33
Options Exercisable (in shares)	32	179
Weighted Average Exercise Price (in dollars per share)	$ 3.30	$ 3.33
Weighted Average Remaining Contractual Life (In years)	9 months 18 days	1 year 4 months 24 days
$3.43 - $3.50
Range of Exercise Prices
Exercise prices, outstanding stock option awards, low end of range (in dollars per share)	$ 3.43	$ 3.43
Exercise prices, outstanding stock option awards, high end of range (in dollars per share)	$ 3.50	$ 3.50
Options Outstanding (in shares)	152	227
Weighted Average Exercise Price (in dollars per share)	$ 3.48	$ 3.48
Options Exercisable (in shares)	152	227
Weighted Average Exercise Price (in dollars per share)	$ 3.48	$ 3.48
Weighted Average Remaining Contractual Life (In years)	1 year 8 months 12 days	2 years 7 months 6 days

Stock-Based Compensation - Restricted Share Units (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Performance-Based Restricted Share Units
Shares Granted
Outstanding at the beginning of the year (in shares)	129	108
Awarded (in shares)	191	155	111
Vested (in shares)	(126)	(102)
Cancelled (in shares)	(190)	(32)	(3)
Outstanding at the end of the year (in shares)	4	129	108
Weighted-Average Grant Date Fair Value
Outstanding at the beginning of the year (in dollars per share)	$ 50.32	$ 27.00
Awarded (in dollars per share)	86.63	50.45	$ 27.00
Vested (in dollars per share)	50.32	27.00
Cancelled (in dollars per share)	86.90	46.42	27.00
Outstanding at the end of the year (in dollars per share)	$ 87.14	$ 50.32	$ 27.00
Unrecognized compensation cost	$ 20	$ 700
Service-Based Restricted share Units
Shares Granted
Outstanding at the beginning of the year (in shares)	3,267	5,458	6,501
Awarded (in shares)	1,406	581	1,806
Vested (in shares)	(1,757)	(2,406)	(2,274)
Cancelled (in shares)	(160)	(366)	(575)
Outstanding at the end of the year (in shares)	2,756	3,267	5,458
Weighted-Average Grant Date Fair Value
Outstanding at the beginning of the year (in dollars per share)	$ 25.45	$ 17.23	$ 13.98
Awarded (in dollars per share)	68.18	62.87	24.94
Vested (in dollars per share)	21.59	17.01	14.73
Cancelled (in dollars per share)	44.00	17.72	14.58
Outstanding at the end of the year (in dollars per share)	$ 48.62	$ 25.45	$ 17.23
Unrecognized compensation cost	$ 112,500
Expected weighted-average recognition period for unrecognized compensation cost	3 years 6 months
Total fair value vested	$ 37,900	$ 40,900	$ 33,500

Other Balance Sheet Components - Accounts Receivable (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounts receivable, net:
Total gross amount	$ 381,522	$ 178,214
Allowance for doubtful accounts:
Balance at the beginning of the year	(8,114)	(6,529)	$ (1,375)
Reversal (additional provision) charged to expenses, net	(6,226)	(5,478)	(7,787)
Write-off	1,911	3,893	2,633
Balance at the end of the year	(12,429)	(8,114)	$ (6,529)
Accounts receivable, net	369,093	170,100
Alibaba
Accounts receivable, net:
Total gross amount	48,222	42,832
Allowance for doubtful accounts:
Balance at the beginning of the year	0
Balance at the end of the year	0	0
Accounts receivable, net	48,222	42,832
Other related parties
Accounts receivable, net:
Total gross amount	131,465	29,696
Allowance for doubtful accounts:
Balance at the beginning of the year	0
Balance at the end of the year	(630)	0
Accounts receivable, net	130,835	29,696
Third parties
Accounts receivable, net:
Total gross amount	201,835	105,686
Allowance for doubtful accounts:
Balance at the beginning of the year	(8,114)
Balance at the end of the year	(11,799)	(8,114)
Accounts receivable, net	$ 190,036	$ 97,572

Other Balance Sheet Components - Prepaid Expenses and Other Current Assets (Details) - USD ($)
$ in Thousands

Dec. 31, 2018

Dec. 31, 2017

Prepaid expenses and other current assets:

Rental and other deposits

$ 684

$ 2,233

Deductible value-added taxes

4,539

Prepayment for investments

106,256

20,881

Advertising prepayment

4,575

3,959

Prepayment to outsourced service providers

4,730

5,369

Amounts deposited by users

^[1]

30,631

25,277

Content fees

11,021

7,393

Others

6,385

4,121

Prepaid expenses and other current assets

$ 168,821

$ 69,233

[1]

Weibo wallet enables users to conduct interest-generation activities on Weibo, such as handing out "red envelopes" and coupons to users and purchase different types of products and services on Weibo, including those offered by the Group, such as marketing services and VIP membership, and those offered by Weibo’s platform partners, such as e-commerce merchandises, financial products and virtual gifts. Amounts deposited by users primarily represent the receivables temporarily held in Weibo’s account on a third party online payment platform for Weibo wallet users. Amounts due to users represent the balances that are payable on demand to Weibo wallet users and therefore are reflected as current liability on the consolidated balance sheets.

Other Balance Sheet Components - Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property and equipment, net:
Property and equipment, gross	$ 133,622	$ 121,694
Less: Accumulated depreciation	(87,999)	(87,901)
Property and equipment, net	45,623	33,793
Computers and equipment
Property and equipment, net:
Property and equipment, gross	124,241	113,558
Leasehold improvements
Property and equipment, net:
Property and equipment, gross	5,008	4,321
Furniture and fixtures
Property and equipment, net:
Property and equipment, gross	1,677	1,241
Others
Property and equipment, net:
Property and equipment, gross	$ 2,696	$ 2,574

Other Balance Sheet Components - Accrued and other Liabilities (Details) - USD ($)
$ in Thousands

Dec. 31, 2018

Dec. 31, 2017

Accrued and other liabilities:

Payroll and welfare

^[1]

$ 56,349

$ 57,848

Marketing expenses

49,998

53,380

Payroll withholding taxes

3,547

Sales rebates

95,121

60,663

Professional fees

8,249

6,170

VAT and other tax payable

48,651

51,563

Payable to other service providers

1,266

362

Amounts due to users

30,631

25,277

Unpaid consideration for acquisition

^[2]

10,000

Others

13,625

9,805

Total accrued and other liabilities

$ 317,437

$ 268,615

[1]

Include amounts due to third parties, employees, related parties (see Note 9) and Weibo wallet users.

[2]

Income Taxes (Details)		12 Months Ended
Income Taxes (Details)	Feb. 22, 2008	Dec. 31, 2018 USD ($) jurisdiction $ / shares	Dec. 31, 2017 USD ($) $ / shares	Dec. 31, 2016 USD ($) $ / shares	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Income taxes
Number of taxable jurisdictions \| jurisdiction		2
Components of income before income taxes
Income before income tax expenses		$ 668,842,000	$ 417,111,000	$ 109,980,000
Add: loss from non-China operations		43,266,000	52,261,000	60,193,000
Income from China operations		712,108,000	469,372,000	170,173,000
Income tax expense applicable to China operations		$ 96,222,000	$ 66,746,000	$ 4,316,000
Effective tax rate for China operations (as a percent)		13.50%	14.20%	2.50%
Impairment on investments		$ 23,557,000	$ 4,747,000	$ 31,586,000
Reclassification from accounts payable to income tax payable in balance sheet			70,900,000
Reclassification from accounts payable to income tax payable in operating activities of consolidated statement of cash flows.		$ 21,000,000	$ 62,300,000	$ 5,100,000
Income tax rate (as a percent)		25.00%	25.00%	25.00%
Composition of income tax expenses for China operations
Deferred tax (benefits)/provisions		$ 4,438,000	$ (1,503,000)	$ (4,630,000)
Current income tax expenses		91,784,000	68,249,000	8,946,000
Income tax expenses		$ 96,222,000	$ 66,746,000	$ 4,316,000
Reconciliation of the statutory tax rate to the effective tax rate for China operations
Statutory EIT rate (as a percent)		25.00%	25.00%	25.00%
Effect on tax holiday and preferential tax treatment (as a percent)		(12.10%)	(11.60%)	(29.60%)
Permanent differences (as a percent)		0.60%	0.20%	1.20%
Change in valuation allowance (as a percent)		0.00%	0.60%	5.90%
Effective tax rate for China operations (as a percent)		13.50%	14.20%	2.50%
Deferred tax assets:
Net operating loss carry forwards		$ 4,180,000	$ 10,280,000
Less: valuation allowance		(4,180,000)	(10,280,000)
Depreciation, accounts receivable, accrued and other liabilities		25,327,000	19,931,000
Less: valuation allowance		(13,419,000)	(11,629,000)
Net deferred tax assets (included in other assets)		11,908,000	8,302,000
Deferred tax liabilities:
Acquired intangible assets		2,310,000	129,000
Depreciation		702,000	527,000
Investment gain		9,565,000
Others			1,224,000
Total deferred tax liabilities		12,577,000	1,880,000
Valuation allowance on deferred tax assets		$ 17,600,000	21,900,000
Historical rate for valuing deferred tax assets (as a percent)		25.00%
Net operating loss carryforwards expired amount		$ 18,600,000
Net operating loss carryforwards utilized amount		0
Weibo Technology
Reconciliation of the statutory tax rate to the effective tax rate for China operations
Effect of tax exemption				$ 50,400,000
Effect of preferential tax treatment		$ 77,200,000	$ 52,600,000
Effect of tax exemption and preferential tax on basic net income per share (USD per share) \| $ / shares		$ 0.39	$ 0.25	$ 0.23
Weibo Technology \| key software enterprise
Reconciliation of the statutory tax rate to the effective tax rate for China operations
Preferential tax treatment recognized		$ 10,800,000
Non-China
Components of income before income taxes
Impairment on investments				$ (23,800,000)
Cayman Islands
Components of income before income taxes
Withholding income tax on dividends distributed by subsidiaries to its immediate holding entity outside China (as a percent)		0.00%
Hong Kong
Components of income before income taxes
Income tax rate (as a percent)		16.50%	16.50%	16.50%
Net operating loss carry forwards		$ 1,400,000
Reconciliation of the statutory tax rate to the effective tax rate for China operations
Statutory EIT rate (as a percent)		16.50%	16.50%	16.50%
China
Components of income before income taxes
Withholding income tax on dividends distributed by subsidiaries to its immediate holding entity outside China (as a percent)		10.00%
Income tax rate (as a percent)		25.00%	25.00%	25.00%	25.00%	25.00%	25.00%	25.00%	25.00%	25.00%	25.00%	25.00%
Net operating loss carry forwards		$ 16,700,000	$ 41,100,000
Maximum percentage of withholding income tax on dividends distributed by subsidiaries to its immediate holding entity in Hong Kong		5.00%
Percentage of ownership interests held by foreign investors		25.00%
Percentage of withholding income tax on dividends distributed by PRC subsidiaries to its immediate holding company in Hong Kong		5.00%
Reconciliation of the statutory tax rate to the effective tax rate for China operations
Statutory EIT rate (as a percent)		25.00%	25.00%	25.00%	25.00%	25.00%	25.00%	25.00%	25.00%	25.00%	25.00%	25.00%
China \| Software enterprise
Components of income before income taxes
Period of income tax exemption	2 years
Reduction in preferential tax rate (as a percent)	50.00%
Preferential statutory rate (as a percent)	12.50%	12.50%	12.50%
Period of reduced preferential income tax rate	3 years
China \| key software enterprise
Components of income before income taxes
Preferential statutory rate (as a percent)			10.00%

Related Party Transactions (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Jan. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Related party transactions
Costs and expenses allocated from SINA(2)		$ 47,334	$ 41,136	$ 25,703
Related party outstanding balance:
Amount due from SINA		105,319	16,356
Accounts receivable due from Alibaba		$ 369,093	170,100
SINA
Related party transactions
Loan agreement term		1 year
Principal and interest expense of loan from SINA		$ 2,000	60,000
Principal and interest income of loan to SINA's subsidiary			62,000
Loan to SINA		149,460	59,534
Loan repaid by SINA		101,060	62,252
Loan to SINA		43,600
Revenue billed through/for service provided to SINA(1)		90,645	64,093	39,285
Costs and expenses allocated from SINA(2)		47,334	41,136	25,703
Other costs and expenses billed by SINA		23,400	22,900	20,300
Related party outstanding balance:
Amount due from SINA		$ 105,319	16,356
Annual interest rate on loan to SINA		4.80%
SINA \| U.S. dollar-denominated Matching Loan from SINA
Related party transactions
Loan agreement term	1 year
Principal and interest expense of loan from SINA			61,500
Interest expense on matching loan from SINA			1,537
SINA \| RMB-denominated Matching Loan to SINA's Subsidiary
Related party transactions
Loan agreement term	1 year
Principal and interest income of loan to SINA's subsidiary			64,000
Interest income on matching loan to SINA			1,735
SINA \| Short-term Loan
Related party transactions
Amount of loan			2,000
Interest income on matching loan to SINA		$ 2,425
Alibaba
Related party transactions
Advertising and marketing revenues from related party		117,696	84,688	57,908
Services provided by Alibaba		47,642	32,734	13,988
Related party outstanding balance:
Accounts receivable due from Alibaba		48,222	42,832
Other related parties
Related party transactions
Advertising and marketing revenues from related party		130,200	71,600	45,600
Related party outstanding balance:
Accounts receivable due from Alibaba		130,835	29,696
Value-added services revenues		24,100	21,400	600
Amount of promotional services from related parties		9,300	4,100	$ 10,600
Accounts receivable due from other related parties		130,800	29,700
Accounts payable due to other related parties		31,200	12,200
Accrued and other liabilities due to other related parties		14,400	$ 5,000
One related party
Related party transactions
Advertising and marketing revenues from related party		53,900
Related party outstanding balance:
Accounts receivable due from other related parties		$ 80,900

Employee Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
Employee Benefit Plans (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
China Contribution Plan
Employee Benefit Plans
Employer contribution under China Contribution Plan	$ 53.7	$ 38.0	$ 31.4

Net Income per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Numerator:
Net income attributable to Weibo	$ 571,823	$ 352,590	$ 108,027
Denominator:
Weighted average ordinary shares outstanding (in shares)	223,751,000	220,555,000	214,745,000
Basic net income per share attributable to Weibo (in dollars per share)	$ 2.56	$ 1.60	$ 0.50
Numerator:
Net income attributable to Weibo	$ 571,823	$ 352,590	$ 108,027
Add: Effect on interest expenses and amortized issuance cost of convertible debt	15,390
Net income attributable for calculating diluted net income per share	$ 587,213	$ 352,590	$ 108,027
Denominator:
Weighted average ordinary shares outstanding (in shares)	223,751,000	220,555,000	214,745,000
Weighted average ordinary shares equivalents:
Shares used in computing diluted net income per share attributable to Weibo (in shares)	232,683,000	225,363,000	222,859,000
Diluted net income per share attributable to Weibo (in dollars per share)	$ 2.52	$ 1.56	$ 0.48
Options and RSUs
Anti-dilutive share
Anti-dilutive share excluded from the calculation of diluted net income per share	60,000	0	30,000
Weighted average ordinary shares equivalents:
Effects of dilutive securities (in shares)	2,200,000	4,800,000	8,100,000
Stock options
Weighted average ordinary shares equivalents:
Effects of dilutive securities (in shares)	283,000	1,213,000	4,334,000
Restricted share units
Weighted average ordinary shares equivalents:
Effects of dilutive securities (in shares)	1,896,000	3,595,000	3,780,000
2022 Notes
Anti-dilutive share
Anti-dilutive share excluded from the calculation of diluted net income per share		1,200,000
Weighted average ordinary shares equivalents:
Effects of dilutive securities for convertible debt (in shares)	6,753,000

Segment Information (Details) $ in Thousands	12 Months Ended
Segment Information (Details) $ in Thousands	Dec. 31, 2018 USD ($) segment	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Summary information by segment
Number of principal business segments \| segment	2
Revenues	$ 1,718,518	$ 1,150,054	$ 655,800
Advertising & Marketing
Summary information by segment
Revenues	1,499,180	996,745	570,982
Value-added services
Summary information by segment
Revenues	$ 219,338	$ 153,309	$ 84,818

Profit Appropriation and Restricted Net Assets (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) fund	Dec. 31, 2017 USD ($)
Profit Appropriation and Restricted Net Assets
Minimum percentage of after-tax profit transferred by Chinese subsidiaries to general reserve fund	10.00%
Maximum percentage criteria for appropriation of after-tax profit of Chinese subsidiaries to general reserve fund	50.00%
Number of reserve funds except general reserve fund, appropriation at the entity's discretion \| fund	2
Minimum percentage of after-tax profit transferred by VIEs to statutory reserve fund	10.00%
Maximum percentage criteria for in appropriation of after-tax profit by VIEs to certain statutory reserve funds	50.00%
Reserves made to non-distributable reserve fund (in dollars)	$ 98.7	$ 73.6
Net assets subject to restriction for the Group (in dollars)	$ 391.5
Percent of restricted net assets of total consolidated net assets	22.40%

Fair Value Measurement - Fair Value Hierarchy (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Fair Value of Financial Instruments
Bank time deposits	$ 591,269	$ 791,730
Available-for-sale equity securities / Equity securities with readily determinable market value		4,279
Financial instruments measured on a recurring basis
Fair Value of Financial Instruments
Bank time deposits	591,269	791,730
Available-for-sale equity securities / Equity securities with readily determinable market value	1,476	4,279
Total	592,745	796,009
Financial instruments measured on a recurring basis \| Quoted Prices in Active Market for Identical Assets (Level 1)
Fair Value of Financial Instruments
Available-for-sale equity securities / Equity securities with readily determinable market value	1,476	4,279
Total	1,476	4,279
Financial instruments measured on a recurring basis \| Significant Other Observable Inputs (Level 2)
Fair Value of Financial Instruments
Bank time deposits	591,269	791,730
Total	$ 591,269	$ 791,730

Fair Value Measurement - Recurring Basis (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financial instruments measured on a recurring basis
Key inputs used in investor option liability valuation
Impairment loss for available-for-sale investments	$ 0	$ 0	$ 4,800,000

Fair Value Measurement - Non-recurring Basis (Details)	12 Months Ended
Fair Value Measurement - Non-recurring Basis (Details)	Dec. 31, 2018 USD ($) item	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Reconciliation of the fair value measurements using significant unobservable inputs
Investment related impairment	$ 24,074,000	$ 4,747,000	$ 40,161,000
Write-down of goodwill	10,600,000	0	0
Non-recurring
Reconciliation of the fair value measurements using significant unobservable inputs
Write-down of goodwill	$ 10,600,000	0	0
Significant Unobservable Inputs (Level 3)
Reconciliation of the fair value measurements using significant unobservable inputs
Valuation technique	us-gaap:ValuationTechniqueDiscountedCashFlowMember
Measurement input	us-gaap:MeasurementInputMarketInterestRatesMember
Significant Unobservable Inputs (Level 3) \| Non-recurring \| Minimum
Reconciliation of the fair value measurements using significant unobservable inputs
Discount rate (as a percent) \| item	0.12
Significant Unobservable Inputs (Level 3) \| Non-recurring \| Maximum
Reconciliation of the fair value measurements using significant unobservable inputs
Discount rate (as a percent) \| item	0.20
Significant Unobservable Inputs (Level 3) \| Non-recurring \| Certain investments under cost method and equity method were measured using significant unobservable inputs
Reconciliation of the fair value measurements using significant unobservable inputs
Investment related impairment	$ 23,600,000	$ 4,700,000	$ 35,400,000

Convertible Debt (Details) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Oct. 31, 2017 USD ($) $ / shares	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Convertible Debt
Net proceeds from issuance of the Notes			$ 879,293
2022 Notes
Convertible Debt
Aggregate principal amount	$ 900,000	$ 900,000
Coupon interest (as a percent)	1.25%	1.25%
Due date of the Notes	Nov. 15, 2022
Initial conversion price (in dollars per ADS) \| $ / shares	$ 133.27
Net proceeds from issuance of the Notes		$ 879,300
Issuance cost		20,700
Interest expense		$ 15,400	$ 2,700
Class A ordinary shares \| 2022 Notes
Convertible Debt
Conversion ratio per ADS	1

Commitments and Contingencies (Details) $ in Thousands		3 Months Ended	12 Months Ended
Commitments and Contingencies (Details) $ in Thousands	Jan. 26, 2018 defendant	Aug. 31, 2017 action	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Oct. 31, 2017 USD ($)
Commitments and Contingencies
Lease expense			$ 11,200	$ 9,200	$ 14,400
Operating lease commitments
Total			31,751
Less than One Year			10,214
One to Three Years			19,544
Three to Five Years			1,993
Purchase commitments
Total			568,852
Less than One Year			564,339
One to Three Years			4,394
Three to Five Years			119
2022 Notes
Total			945,000
Less than One Year			12,750
One to Three Years			22,500
Three to Five Years			909,750
Two putative securities class actions
Contingency
Number of putative securities class actions filed in June and August 2017 \| action		2
Number of individual defendants filed motion to dismiss the amended complaint \| defendant	1
2022 Notes
2022 Notes
Aggregate principal amount			$ 900,000			$ 900,000
Interest rate (as a percent)			1.25%			1.25%