Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2016		167,431
Beginning balance at Dec. 31, 2016	$ 541,093	$ 167	$ 1,405,317	$ (841,718)	$ (22,673)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under employee stock plans (in shares)		7,386
Common stock issued under employee stock plans	82,559	$ 7	82,552
Repurchases and retirement of common stock (in shares)		(541)
Repurchases and retirement of common stock	(55,000)		(55,000)
Taxes paid related to net share settlement of equity awards	(182,127)		(182,127)
Stock-based compensation	394,680		394,680
Equity component of the convertible notes, net	159,891		159,891
Purchase of convertible note hedge	(128,017)		(128,017)
Issuance of warrants	54,071		54,071
Other comprehensive income (loss), net of tax	28,440				28,440
Net loss	(116,846)			(116,846)
Ending balance (in shares) at Dec. 31, 2017		174,276
Ending balance at Dec. 31, 2017	778,744	$ 174	1,731,367	(958,564)	5,767
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment for ASU adoption | Accounting Standards Update 2016-01				7,234	(7,234)
Cumulative effect adjustment for ASU adoption | Accounting Standards Update 2016-16	(746)			(746)
Common stock issued under employee stock plans (in shares)		5,899
Common stock issued under employee stock plans	104,173	$ 6	104,167
Taxes paid related to net share settlement of equity awards	(281,061)		(281,061)
Stock-based compensation	545,805		545,805
Settlement of 2018 Notes conversion feature (in shares)		1,314
Settlement of 2018 Notes conversion feature	$ (773,301)	$ 1	(773,302)
Benefit from exercise of 2018 Note Hedges (in shares)	1,300	(1,314)
Benefit from exercise of 2018 Note Hedges	$ 766,857	$ (1)	766,858
Other comprehensive income (loss), net of tax	(2,568)				(2,568)
Net loss	(26,704)			(26,704)
Ending balance (in shares) at Dec. 31, 2018		180,175
Ending balance at Dec. 31, 2018	1,111,199	$ 180	2,093,834	(978,780)	(4,035)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment for ASU adoption | Accounting Standards Update 2016-02	(162)			(162)
Common stock issued under employee stock plans (in shares)		5,003
Common stock issued under employee stock plans	107,909	$ 4	107,905
Taxes paid related to net share settlement of equity awards	(409,703)		(409,703)
Stock-based compensation	662,710		662,710
Stock Issued During Period, Shares, Settlement Of Warrants		4,283
Settlement of 2018 Warrants		$ 5	(5)
Other comprehensive income (loss), net of tax	29,290				29,290
Net loss	626,698			626,698
Ending balance (in shares) at Dec. 31, 2019		189,461
Ending balance at Dec. 31, 2019	$ 2,127,941	$ 189	$ 2,454,741	$ (352,244)	$ 25,255