CONSOLIDATED AND CONDENSED STATEMENTS OF STOCKHOLDERS' DEFICIT - USD ($) shares in Thousands, $ in Thousands	Total	Class A and Class B Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Loss
Balance (in shares) at Dec. 31, 2017		88,209
Balance at Dec. 31, 2017	$ (48,329)	$ 88	$ 537,212	$ (583,266)	$ (2,363)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(360,235)			(360,235)
Other comprehensive income	296				296
Exercise of options to purchase common stock (in shares)		35
Exercise of options to purchase common stock	104		104
Issuance of common stock upon vesting of RSUs (in shares)		1,893
Issuance of common stock upon vesting of RSUs	2	$ 2
Shares withheld related to net settlement of RSUs (in shares)		(10)
Shares withheld related to net settlement of RSUs	(1,097)		(1,097)
Equity compensation expense	92,381		92,381
Balance (in shares) at Sep. 30, 2018		90,127
Balance at Sep. 30, 2018	(312,221)	$ 90	628,600	(938,844)	(2,067)
Balance (in shares) at Jun. 30, 2018		89,477
Balance at Jun. 30, 2018	(195,478)	$ 89	593,460	(787,118)	(1,909)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(151,726)			(151,726)
Other comprehensive income	(158)				(158)
Exercise of options to purchase common stock (in shares)		10
Exercise of options to purchase common stock	30		30
Issuance of common stock upon vesting of RSUs (in shares)		642
Issuance of common stock upon vesting of RSUs	1	$ 1
Shares withheld related to net settlement of RSUs (in shares)		(2)
Shares withheld related to net settlement of RSUs	(462)		(462)
Equity compensation expense	35,572		35,572
Balance (in shares) at Sep. 30, 2018		90,127
Balance at Sep. 30, 2018	(312,221)	$ 90	628,600	(938,844)	(2,067)
Balance (in shares) at Dec. 31, 2018		90,748
Balance at Dec. 31, 2018	(330,721)	$ 91	753,657	(1,082,689)	(1,780)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(654,362)			(654,362)
Other comprehensive income	324				324
Exercise of options to purchase common stock (in shares)		28
Exercise of options to purchase common stock	90		90
Issuance of common stock upon vesting of RSUs (in shares)		2,109
Issuance of common stock upon vesting of RSUs	2	$ 2
Shares withheld related to net settlement of RSUs (in shares)		(11)
Shares withheld related to net settlement of RSUs	(1,510)		(1,510)
Equity compensation expense	171,332		171,332
Equity component of issuance of convertible notes and capped calls, net (Note 14)	130,566		130,566
Balance (in shares) at Sep. 30, 2019		92,874
Balance at Sep. 30, 2019	(682,429)	$ 93	1,054,135	(1,735,201)	(1,456)
Balance (in shares) at Jun. 30, 2019		92,098
Balance at Jun. 30, 2019	(605,357)	$ 93	859,092	(1,463,166)	(1,376)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(272,035)			(272,035)
Other comprehensive income	(80)				(80)
Exercise of options to purchase common stock (in shares)		3
Exercise of options to purchase common stock	10		10
Issuance of common stock upon vesting of RSUs (in shares)		781
Issuance of common stock upon vesting of RSUs	0
Shares withheld related to net settlement of RSUs (in shares)		(8)
Shares withheld related to net settlement of RSUs	(1,086)		(1,086)
Equity compensation expense	65,553		65,553
Equity component of issuance of convertible notes and capped calls, net (Note 14)	130,566		130,566
Balance (in shares) at Sep. 30, 2019		92,874
Balance at Sep. 30, 2019	$ (682,429)	$ 93	$ 1,054,135	$ (1,735,201)	$ (1,456)