Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Cumulative Effect, Period Of Adoption, Adjustment	Cumulative Effect, Period Of Adoption, Adjustment Accumulated Deficit
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative affect adjustment for Topic 842 adoption	$ 1,111,199	$ 180	$ 2,093,834	$ (978,780)	$ (4,035)	$ (162)	$ (162)
Beginning balance (in shares) at Dec. 31, 2018		180,175,000
Beginning balance at Dec. 31, 2018	1,111,199	$ 180	2,093,834	(978,780)	(4,035)	(162)	(162)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative affect adjustment for Topic 842 adoption	$ 1,111,199	$ 188	2,238,782	(978,780)	(4,035)	$ (162)	$ (162)
Common stock issued under employee stock plans (in shares)	3,000,000.0	3,003,000
Common stock issued under employee stock plans	$ 63,309	$ 3	63,306
Taxes paid related to net share settlement of equity awards	(247,620)		(247,620)
Stock-based compensation	329,267		329,267
Settlement of 2018 Warrants (in shares)		4,283,000
Settlement of 2018 Warrants		$ 5	(5)
Other comprehensive income (loss), net	17,577				17,577
Net income (loss)	(12,624)			(12,624)
Ending balance (in shares) at Jun. 30, 2019		187,461,000
Ending balance at Jun. 30, 2019	$ 1,260,946	$ 188	2,238,782	(991,566)	13,542
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201602Member
Cumulative affect adjustment for Topic 842 adoption	$ 1,194,951	$ 185	2,164,930	(980,487)	10,323
Beginning balance (in shares) at Mar. 31, 2019		184,739,000
Beginning balance at Mar. 31, 2019	1,194,951	$ 185	2,164,930	(980,487)	10,323
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative affect adjustment for Topic 842 adoption	1,260,946	$ 188	2,238,782	(991,566)	13,542
Common stock issued under employee stock plans (in shares)		1,120,000
Common stock issued under employee stock plans	10,207	$ 1	10,206
Taxes paid related to net share settlement of equity awards	(108,150)		(108,150)
Stock-based compensation	171,798		171,798
Settlement of 2018 Warrants (in shares)		1,602,000
Settlement of 2018 Warrants		$ 2	(2)
Other comprehensive income (loss), net	3,219				3,219
Net income (loss)	(11,079)			(11,079)
Ending balance (in shares) at Jun. 30, 2019		187,461,000
Ending balance at Jun. 30, 2019	1,260,946	$ 188	2,238,782	(991,566)	13,542
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative affect adjustment for Topic 842 adoption	1,260,946	188	2,238,782	(991,566)	13,542
Cumulative affect adjustment for Topic 842 adoption	2,127,941	$ 189	2,454,741	(352,244)	25,255
Beginning balance (in shares) at Dec. 31, 2019		189,461,000
Beginning balance at Dec. 31, 2019	2,127,941	$ 189	2,454,741	(352,244)	25,255
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative affect adjustment for Topic 842 adoption	$ 2,478,806	$ 191	2,454,741	(352,244)	29,772
Common stock issued under employee stock plans (in shares)	2,300,000	2,340,000
Common stock issued under employee stock plans	$ 91,054	$ 2	91,052
Taxes paid related to net share settlement of equity awards	(238,551)		(238,551)
Stock-based compensation	405,739		405,739
Settlement of 2022 Notes conversion feature	(22,755)		(22,755)
Benefit from exercise of 2022 Note Hedge	21,864		21,864
Other comprehensive income (loss), net	4,517				4,517
Net income (loss)	88,997			88,997
Ending balance (in shares) at Jun. 30, 2020		191,801,000
Ending balance at Jun. 30, 2020	2,478,806	$ 191	2,712,090	(263,247)	29,772
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative affect adjustment for Topic 842 adoption	2,266,095	$ 190	2,584,298	(304,013)	(14,380)
Beginning balance (in shares) at Mar. 31, 2020		190,700,000
Beginning balance at Mar. 31, 2020	2,266,095	$ 190	2,584,298	(304,013)	(14,380)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative affect adjustment for Topic 842 adoption	2,478,806	$ 191	2,712,090	(263,247)	29,772
Common stock issued under employee stock plans (in shares)		1,101,000
Common stock issued under employee stock plans	24,179	$ 1	24,178
Taxes paid related to net share settlement of equity awards	(112,845)		(112,845)
Stock-based compensation	217,174		217,174
Settlement of 2018 Warrants	0
Settlement of 2022 Notes conversion feature	(19,027)		(19,027)
Benefit from exercise of 2022 Note Hedge	18,312		18,312
Other comprehensive income (loss), net	44,152				44,152
Net income (loss)	40,766			40,766
Ending balance (in shares) at Jun. 30, 2020		191,801,000
Ending balance at Jun. 30, 2020	2,478,806	$ 191	2,712,090	(263,247)	29,772
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative affect adjustment for Topic 842 adoption	$ 2,478,806	$ 191	$ 2,712,090	$ (263,247)	$ 29,772