Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Class A,B, and C Common Stock [Member]	Additional Paid-In Capital [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]
Beginning balance, Value at Dec. 31, 2016	$ 1,580,664	$ 6	$ 3,349,708		$ (128,694)	$ (1,640,356)
Beginning balance, Shares at Dec. 31, 2016		886,850,000
Exercise of stock options and ESPP	8,769		8,769
Exercise of stock options and ESPP, Shares		5,365,000
Vesting of ZSUs, net of tax withholdings	(21,719)		(427)	$ (21,292)
Vesting of ZSUs, net of tax withholdings, Shares		14,768,000
Stock-based compensation expense	64,515		64,515
Repurchases of common stock, Value	(101,036)	$ (1)		(101,035)
Repurchases of common stock, Shares		(36,323,000)
Retirements of treasury stock				122,327		(122,327)
Adoption of ASU | 2016-09	48,211		3,935			44,276
Net income (loss)	26,639					26,639
Other comprehensive income (loss)	35,197				35,197
Ending balance, Value at Dec. 31, 2017	1,641,240	$ 5	3,426,500		(93,497)	(1,691,768)
Ending balance, Shares at Dec. 31, 2017		870,660,000
Exercise of stock options and ESPP	9,969		9,969
Exercise of stock options and ESPP, Shares		5,090,000
Vesting of ZSUs, net of tax withholdings	(25,807)			(25,807)
Vesting of ZSUs, net of tax withholdings, Shares		10,618,000
Stock-based compensation expense	68,239		68,239
Repurchases of common stock, Value	(91,570)			(91,570)
Repurchases of common stock, Shares		(25,257,000)
Retirements of treasury stock				117,377		(117,377)
Adoption of ASU | 2014-09	4,024					4,024
Net income (loss)	15,457					15,457
Other comprehensive income (loss)	(24,942)				(24,942)
Ending balance, Value at Dec. 31, 2018	1,596,610	$ 5	3,504,708		(118,439)	(1,789,664)
Ending balance, Shares at Dec. 31, 2018		861,111,000
Exercise of stock options and ESPP	17,488		17,488
Exercise of stock options and ESPP, Shares		12,007,000
Vesting of ZSUs, net of tax withholdings	(49,591)			(49,591)
Vesting of ZSUs, net of tax withholdings, Shares		13,129,000
Acquisition-related common stockissuance	253,904	$ 1	253,903
Acquisition-related common stock issuance, Shares		63,795,000
Stock-based compensation expense	81,482		81,482
Retirements of treasury stock				$ 49,591		(49,591)
Equity component of convertible senior notes	114,938		114,938
Purchase of capped calls related toissuance of convertible senior notes	(73,830)		(73,830)
Net income (loss)	41,925					41,925
Other comprehensive income (loss)	(7,496)				(7,496)
Ending balance, Value at Dec. 31, 2019	$ 1,975,430	$ 6	$ 3,898,689		$ (125,935)	$ (1,797,330)
Ending balance, Shares at Dec. 31, 2019		950,042,000