Condensed Consolidated Statements of Redeemable Noncontrolling Interest, Total Stockholders' Deficit and Noncontrolling Interest (Unaudited) - USD ($) $ in Thousands	Total	Total Stockholders' Deficit	Total Stockholders' Deficit Cumulative effect upon adoption of new accounting standard	Redeemable Noncontrolling  Interest	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Accumulated Deficit Cumulative effect upon adoption of new accounting standard	Noncontrolling Interest	Noncontrolling Interest Cumulative effect upon adoption of new accounting standard
Beginning balance at Dec. 31, 2018		$ (142,610)		$ 57,261	$ 11	$ 2,481,352	$ 131	$ (2,624,104)		$ 125,110
Beginning balance (Accounting Standards Update 2017-12) at Dec. 31, 2018			$ 130						$ 130		$ (130)
Beginning balance (Accounting Standards Update 2014-09) at Dec. 31, 2018			$ (17,996)						$ (17,996)
Beginning balance (in shares) at Dec. 31, 2018					109,421,183
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of restricted stock awards (in shares)					6,341,441
Issuance of restricted stock awards		1			$ 1
ESPP purchase (in shares)					1,718,433
ESPP purchase		11,183				11,183
Exercise of stock options (in shares)					336,572
Exercise of stock options		1,440				1,440
Stock-based compensation expense		153,898				153,898
Unrealized gain (loss) on available-for-sale securities	$ 14	14					14
Change in effective portion of interest rate swap agreement	(8,137)	(292)					(292)			(7,845)
Distributions to noncontrolling interests				(3,825)						(5,250)
Mandatory redemption of noncontrolling interests				(55,684)
Net income (loss)	(252,455)	(238,581)		2,805				(238,581)		(16,679)
Ending balance at Sep. 30, 2019		(232,812)		557	$ 12	2,647,873	(147)	(2,880,551)		95,206
Ending balance (in shares) at Sep. 30, 2019					117,817,629
Beginning balance at Jun. 30, 2019		(224,904)		505	$ 11	2,604,034	(148)	(2,828,801)		104,072
Beginning balance (in shares) at Jun. 30, 2019					113,949,343
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of restricted stock awards (in shares)					2,837,343
Issuance of restricted stock awards		1			$ 1
ESPP purchase (in shares)					1,022,397
ESPP purchase		4,267				4,267
Exercise of stock options (in shares)					8,546
Exercise of stock options		35				35
Stock-based compensation expense		39,537				39,537
Unrealized gain (loss) on available-for-sale securities	(12)	(12)					(12)
Change in effective portion of interest rate swap agreement	(2,444)	13					13			(2,457)
Distributions to noncontrolling interests				(288)						(1,042)
Net income (loss)	(56,777)	(51,750)		340				(51,750)		(5,367)
Ending balance at Sep. 30, 2019		(232,812)		557	$ 12	2,647,873	(147)	(2,880,551)		95,206
Ending balance (in shares) at Sep. 30, 2019					117,817,629
Beginning balance at Dec. 31, 2019		(259,594)		443	$ 12	2,686,759	19	(2,946,384)		91,291
Beginning balance (in shares) at Dec. 31, 2019					121,036,289
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of notes (in shares)					23,854,441
Conversion of notes		201,472			$ 2	201,470
Issuance of convertible note		124,050				124,050
Adjustment of embedded derivative for debt modification		(24,071)				(24,071)
Issuance of restricted stock awards (in shares)					6,524,088
Issuance of restricted stock awards		1			$ 1
ESPP purchase (in shares)					1,937,825
ESPP purchase		8,500				8,500
Exercise of stock options (in shares)					443,929
Exercise of stock options		4,243				4,243
Stock-based compensation expense		53,425				53,425
Unrealized gain (loss) on available-for-sale securities	(23)	(23)					(23)
Change in effective portion of interest rate swap agreement	(8,144)	(5)					(5)			(8,139)
Distributions to noncontrolling interests				(35)						(5,696)
Proceeds from noncontrolling interest										4,314
Net income (loss)	(147,496)	(130,415)		(219)				(130,415)		(16,861)
Ending balance at Sep. 30, 2020		(22,418)		189	$ 15	3,054,376	(9)	(3,076,800)		64,909
Ending balance (in shares) at Sep. 30, 2020					153,796,572
Beginning balance at Jun. 30, 2020		(316,951)		118	$ 13	2,747,890	(9)	(3,064,846)		66,302
Beginning balance (in shares) at Jun. 30, 2020					130,238,289
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of notes (in shares)					19,136,313
Conversion of notes		160,342			$ 1	160,341
Issuance of convertible note	124,050
Issuance of restricted stock awards (in shares)					3,203,935
Issuance of restricted stock awards		1			$ 1
ESPP purchase (in shares)					944,979
ESPP purchase		4,323				4,323
Exercise of stock options (in shares)					273,056
Exercise of stock options		3,235				3,235
Stock-based compensation expense		14,537				14,537
Unrealized gain (loss) on available-for-sale securities	0
Change in effective portion of interest rate swap agreement	573									573
Distributions to noncontrolling interests				(18)						(269)
Proceeds from noncontrolling interest										4,314
Net income (loss)	$ (17,876)	(11,954)		89				(11,954)		(6,011)
Ending balance at Sep. 30, 2020		$ (22,418)		$ 189	$ 15	$ 3,054,376	$ (9)	$ (3,076,800)		$ 64,909
Ending balance (in shares) at Sep. 30, 2020					153,796,572