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)					3,504,098
ESPP purchase (in shares)					696,036
ESPP purchase		6,916				6,916
Exercise of stock options (in shares)					328,026
Exercise of stock options		1,405				1,405
Stock-based compensation expense		114,361				114,361
Unrealized gain (loss) on available-for-sale securities	$ 26	26					26
Change in effective portion of interest rate swap agreement	(5,693)	(305)					(305)			(5,388)
Distributions to noncontrolling interests				(3,537)						(4,208)
Mandatory redemption of noncontrolling interests				(55,684)
Net income (loss)	(195,678)	(186,831)		2,465				(186,831)		(11,312)
Ending balance at Jun. 30, 2019		(224,904)		505	$ 11	2,604,034	(148)	(2,828,801)		104,072
Ending balance (in shares) at Jun. 30, 2019					113,949,343
Beginning balance at Mar. 31, 2019		(194,863)		58,802	$ 11	2,552,011	5	(2,746,890)		114,664
Beginning balance (in shares) at Mar. 31, 2019					113,214,063
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of restricted stock awards (in shares)					543,636
Issuance of restricted stock awards		0			$ 0
Exercise of stock options (in shares)					191,644
Exercise of stock options		828				828
Stock-based compensation expense		51,195				51,195
Unrealized gain (loss) on available-for-sale securities	9	9					9
Change in effective portion of interest rate swap agreement	(3,502)	(162)					(162)			(3,340)
Distributions to noncontrolling interests				(3,255)						(1,595)
Mandatory redemption of noncontrolling interests				(55,684)
Net income (loss)	(86,926)	(81,911)		642				(81,911)		(5,657)
Ending balance at Jun. 30, 2019		(224,904)		505	$ 11	2,604,034	(148)	(2,828,801)		104,072
Ending balance (in shares) at Jun. 30, 2019					113,949,343
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)					4,718,128
Conversion of notes		41,130			$ 1	41,129
Adjustment of embedded derivative for debt modification		(24,071)				(24,071)
Issuance of restricted stock awards (in shares)					3,320,153
ESPP purchase (in shares)					992,846
ESPP purchase		4,177				4,177
Exercise of stock options (in shares)					170,873
Exercise of stock options		1,008				1,008
Stock-based compensation expense		38,888				38,888
Unrealized gain (loss) on available-for-sale securities	(23)	(23)					(23)
Change in effective portion of interest rate swap agreement	(8,717)	(5)					(5)			(8,712)
Distributions to noncontrolling interests				(17)						(5,427)
Net income (loss)	(129,620)	(118,461)		(308)				(118,461)		(10,850)
Ending balance at Jun. 30, 2020		(316,951)		118	$ 13	2,747,890	(9)	(3,064,845)		66,302
Ending balance (in shares) at Jun. 30, 2020					130,238,289
Beginning balance at Mar. 31, 2020		(333,099)		67	$ 12	2,689,208	14	(3,022,333)		73,867
Beginning balance (in shares) at Mar. 31, 2020					125,150,690
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of notes (in shares)					4,718,128
Conversion of notes		41,130			$ 1	41,129
Issuance of restricted stock awards (in shares)					309,547
Issuance of restricted stock awards		0			$ 0
Exercise of stock options (in shares)					59,924
Exercise of stock options		341				341
Stock-based compensation expense		17,212				17,212
Unrealized gain (loss) on available-for-sale securities	(23)	(23)					(23)
Change in effective portion of interest rate swap agreement	(503)									(503)
Distributions to noncontrolling interests				(16)						(1,530)
Net income (loss)	$ (47,978)	(42,512)		67				(42,512)		(5,532)
Ending balance at Jun. 30, 2020		$ (316,951)		$ 118	$ 13	$ 2,747,890	$ (9)	$ (3,064,845)		$ 66,302
Ending balance (in shares) at Jun. 30, 2020					130,238,289