CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Convertible preferred stock	Class A and B common stock	Additional paid-in capital	Accumulated other comprehensive income (loss)	Accumulated deficit
Beginning balance (in shares) at Dec. 31, 2016		0	364,547,376
Beginning balance at Dec. 31, 2016	$ 576,153	$ 0	$ 0	$ 1,357,381	$ (1,989)	$ (779,239)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(62,813)					(62,813)
Shares issued in connection with:
Exercise of stock options (in shares)			24,510,745
Exercise of stock options	144,774			144,774
Vesting of early exercised stock options and other	661			661
Purchases under employee stock purchase plan (in shares)			1,670,045
Purchases under employee stock purchase plan	17,859			17,859
Vesting of restricted stock units (in shares)			5,964,153
Repurchase of common stock (in shares)			(24,209)
Change in other comprehensive loss	671				671
Share-based compensation	159,509			159,509
Tax withholding related to vesting of restricted stock units (in shares)			(1,474,035)
Tax withholding related to vesting of restricted stock units	(44,682)			(44,682)
Conversion feature of convertible senior notes, due 2022, net of allocated debt issuance costs	83,901			83,901
Purchase of bond hedges in conjunction with issuance of convertible senior notes, due 2022	(92,136)			(92,136)
Sale of warrants in conjunction with issuance of convertible senior notes, due 2022	57,244			57,244
Payment for termination of Starbucks warrant	(54,808)			(54,808)
Ending balance at Dec. 31, 2017	786,333	$ 0	$ 0	1,630,386	(1,318)	(842,735)
Ending balance (in shares) at Dec. 31, 2017		0	395,194,075
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(38,453)					(38,453)
Shares issued in connection with:
Exercise of stock options (in shares)			13,402,680
Exercise of stock options	106,962			106,962
Vesting of early exercised stock options and other	177			177
Purchases under employee stock purchase plan (in shares)			826,356
Purchases under employee stock purchase plan	26,888			26,888
Vesting of restricted stock units (in shares)			8,046,640
Issuance of common stock in connection with business combination (shares)			2,649,590
Issuance of common stock in connection with business combination	140,107			140,107
Replacement stock awards issued in connection with acquisition (in shares)			24,613
Replacement stock awards issued in connection with acquisition	899			899
Change in other comprehensive loss	(4,735)				(4,735)
Share-based compensation	226,182			226,182
Tax withholding related to vesting of restricted stock units (in shares)			(3,013,394)
Tax withholding related to vesting of restricted stock units	(189,124)			(189,124)
Conversion feature of convertible senior notes, due 2022, net of allocated debt issuance costs	154,019			154,019
Purchase of bond hedges in conjunction with issuance of convertible senior notes, due 2022	(172,586)			(172,586)
Sale of warrants in conjunction with issuance of convertible senior notes, due 2022	112,125			112,125
Issuance of common stock in conjunction with the conversion of senior notes, due 2022 (in shares)			7,288,907
Issuance of common stock in conjunction with the conversion of senior notes, due 2022	$ (20,962)			(20,962)
Exercise of bond hedges in conjunction with the conversion of senior notes, due 2022 (in shares)			(6,901,567)
Recovery of common stock in connection with indemnification settlement agreement (in shares)	(469,894)		(469,894)
Recovery of common stock in connection with indemnification settlement agreement	$ (2,745)			(2,745)
Ending balance at Dec. 31, 2018	1,120,501	$ 0	$ 0	2,012,328	(6,053)	(885,774)
Ending balance (in shares) at Dec. 31, 2018		0	417,048,006
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ 375,446					375,446
Shares issued in connection with:
Exercise of stock options (in shares)	10,176,170		10,176,170
Exercise of stock options	$ 82,340			82,340
Vesting of early exercised stock options and other (in shares)	426
Vesting of early exercised stock options and other	$ 36			36
Purchases under employee stock purchase plan (in shares)			673,661
Purchases under employee stock purchase plan	36,174			36,174
Vesting of restricted stock units (in shares)			8,338,035
Cancellation of restricted stock awards (in shares)			(90,342)
Change in other comprehensive loss	7,682				7,682
Share-based compensation	306,201			306,201
Tax withholding related to vesting of restricted stock units (in shares)			(3,077,807)
Tax withholding related to vesting of restricted stock units	(212,264)			(212,264)
Issuance of common stock in conjunction with the conversion of senior notes, due 2022 (in shares)			127
Issuance of common stock in conjunction with the conversion of senior notes, due 2022	$ 3			3
Exercise of bond hedges in conjunction with the conversion of senior notes, due 2022 (in shares)			(250,763)
Recovery of common stock in connection with indemnification settlement agreement (in shares)	(20,793)		(20,793)
Recovery of common stock in connection with indemnification settlement agreement	$ (1,069)			(1,069)
Ending balance at Dec. 31, 2019	$ 1,715,050	$ 0	$ 0	$ 2,223,749	$ 1,629	$ (510,328)
Ending balance (in shares) at Dec. 31, 2019		0	432,796,720