CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Treasury Stock	Other Comprehensive Income (Loss)
Balance beginning (in shares) at Dec. 31, 2019		32,399,352
Balance beginning at Dec. 31, 2019	$ (186,017)	$ 324	$ 1,260,551	$ (1,431,801)	$ (2,583)	$ (12,508)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Non-cash stock-based compensation	77,602		77,602
Preferred stock beneficial conversion feature	0		24,139	(24,139)
Stock issued under incentive programs (in shares)		1,884,399
Stock issued under incentive programs	(2,916)	$ 19	35,689		(38,624)
Issuance of common stock, net of issuance costs (in shares)		29,035,137
Issuance of common stock, net of issuance costs	450,953	$ 290	450,663
Unrealized loss on marketable securities	18					18
Foreign currency translation adjustment	7,495					7,495
Net loss	(240,695)			(240,695)
Balance ending (in shares) at Sep. 30, 2020		63,318,888
Balance ending at Sep. 30, 2020	106,440	$ 633	1,848,644	(1,696,635)	(41,207)	(4,995)
Balance beginning (in shares) at Jun. 30, 2020		61,262,632
Balance beginning at Jun. 30, 2020	184,526	$ 612	1,699,072	(1,499,325)	(2,638)	(13,195)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Non-cash stock-based compensation	65,705		65,705
Stock issued under incentive programs (in shares)		1,534,345
Stock issued under incentive programs	(11,871)	$ 16	26,682		(38,569)
Issuance of common stock, net of issuance costs (in shares)		521,911
Issuance of common stock, net of issuance costs	57,190	$ 5	57,185
Unrealized loss on marketable securities	(26)					(26)
Foreign currency translation adjustment	8,226					8,226
Net loss	(197,310)			(197,310)
Balance ending (in shares) at Sep. 30, 2020		63,318,888
Balance ending at Sep. 30, 2020	106,440	$ 633	1,848,644	(1,696,635)	(41,207)	(4,995)
Balance beginning (in shares) at Dec. 31, 2020		71,350,365
Balance beginning at Dec. 31, 2020	627,209	$ 714	2,535,476	(1,874,199)	(41,806)	7,024
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Non-cash stock-based compensation	151,457		151,457
Stock issued under incentive programs (in shares)		2,044,191
Stock issued under incentive programs	21,441	$ 20	58,747		(37,326)
Issuance of common stock, net of issuance costs (in shares)		2,578,967
Issuance of common stock, net of issuance costs	564,859	$ 26	564,833
Unrealized loss on marketable securities	(9)					(9)
Foreign currency translation adjustment	(6,154)					(6,154)
Net loss	(897,467)			(897,467)
Balance ending (in shares) at Sep. 30, 2021		75,973,523
Balance ending at Sep. 30, 2021	461,336	$ 760	3,310,513	(2,771,666)	(79,132)	861
Balance beginning (in shares) at Jun. 30, 2021		74,672,351
Balance beginning at Jun. 30, 2021	745,562	$ 747	3,237,085	(2,449,235)	(47,205)	4,170
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Non-cash stock-based compensation	45,274		45,274
Stock issued under incentive programs (in shares)		1,301,172
Stock issued under incentive programs	(3,760)	$ 13	28,154		(31,927)
Foreign currency translation adjustment	(3,309)					(3,309)
Net loss	(322,431)			(322,431)
Balance ending (in shares) at Sep. 30, 2021		75,973,523
Balance ending at Sep. 30, 2021	$ 461,336	$ 760	$ 3,310,513	$ (2,771,666)	$ (79,132)	$ 861