Condensed Consolidated Statements of Changes in Stockholder's Equity (Deficit) (Unaudited) - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Additional Paid-In Capital [Member] Cumulative Effect, Period of Adoption, Adjustment [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]	Accumulated Deficit [Member] Cumulative Effect, Period of Adoption, Adjustment [Member]
Beginning balance at Dec. 31, 2020	$ 204,557	$ (149,734)	$ 8	$ 1,131,013	$ (165,747)	$ (117)	$ (926,347)	$ 16,013
Beginning balance, Shares at Dec. 31, 2020			76,130,000
Accounting Standards Update description	ASU 2020-06
Issuance of shares in exchange of 2019 Convertible Notes, including issuance costs	$ 162,258			162,258
Issuance of shares in exchange of 2019 Convertible Notes, including issuance costs, shares			3,976,000
Forfeiture of accrued interest in exchange of 2019 Convertible Notes	1,668			1,668
Issuance of common stock upon exercise of stock options	2,588			2,588
Issuance of common stock upon exercise of stock options, shares			285,000
Vesting of restricted stock units, net of shares withheld for taxes	(956)			(956)
Vesting of restricted stock units, net of shares withheld for taxes. shares			47,000
Share-based compensation expense	16,439			16,439
Unrealized gain (loss) on available-for-sale investments	79					79
Net loss	(183,659)						(183,659)
Foreign currency gain (loss)	(1,582)					(1,582)
Ending balance at Mar. 31, 2021	51,658		$ 8	1,147,263		(1,620)	(1,093,993)
Ending balance, Shares at Mar. 31, 2021			80,438,000
Beginning balance at Dec. 31, 2020	204,557	$ (149,734)	$ 8	1,131,013	$ (165,747)	(117)	(926,347)	$ 16,013
Beginning balance, Shares at Dec. 31, 2020			76,130,000
Unrealized gain (loss) on available-for-sale investments	44
Net loss	(402,850)
Foreign currency gain (loss)	(1,756)
Ending balance at Jun. 30, 2021	(141,493)		$ 8	1,173,512		(1,829)	(1,313,184)
Ending balance, Shares at Jun. 30, 2021			80,956,000
Beginning balance at Mar. 31, 2021	51,658		$ 8	1,147,263		(1,620)	(1,093,993)
Beginning balance, Shares at Mar. 31, 2021			80,438,000
Issuance of common stock upon exercise of stock options	7,062			7,062
Issuance of common stock upon exercise of stock options, shares			444,000
Vesting of restricted stock units, net of shares withheld for taxes	(233)			(233)
Vesting of restricted stock units, net of shares withheld for taxes. shares			11,000
Share-based compensation expense	17,722			17,722
Issuance of common stock to employee stock purchase plan	1,698			1,698
Issuance of common stock to employee stock purchase plan, shares			63,000
Unrealized gain (loss) on available-for-sale investments	(35)					(35)
Net loss	(219,191)						(219,191)
Foreign currency gain (loss)	(174)					(174)
Ending balance at Jun. 30, 2021	(141,493)		$ 8	1,173,512		(1,829)	(1,313,184)
Ending balance, Shares at Jun. 30, 2021			80,956,000
Beginning balance at Dec. 31, 2021	198,662		$ 10	1,857,430		(2,090)	(1,656,688)
Beginning balance, Shares at Dec. 31, 2021			97,524,000
Common Stock -follow-on-offering	380,120		$ 1	380,119
Common Stock -follow-on-offering, shares			8,564,000
Issuance of common stock upon exercise of stock options	4,000			4,000
Issuance of common stock upon exercise of stock options, shares			239,000
Vesting of restricted stock units, net of shares withheld for taxes	(2,416)			(2,416)
Vesting of restricted stock units, net of shares withheld for taxes. shares			113,000
Share-based compensation expense	20,773			20,773
Unrealized gain (loss) on available-for-sale investments	(52)					(52)
Net loss	(138,935)						(138,935)
Foreign currency gain (loss)	83					83
Ending balance at Mar. 31, 2022	462,235		$ 11	2,259,906		(2,059)	(1,795,623)
Ending balance, Shares at Mar. 31, 2022			106,440,000
Beginning balance at Dec. 31, 2021	198,662		$ 10	1,857,430		(2,090)	(1,656,688)
Beginning balance, Shares at Dec. 31, 2021			97,524,000
Unrealized gain (loss) on available-for-sale investments	(818)
Net loss	(294,912)
Foreign currency gain (loss)	(286)
Ending balance at Jun. 30, 2022	334,418		$ 11	2,289,201		(3,194)	(1,951,600)
Ending balance, Shares at Jun. 30, 2022			106,841,000
Beginning balance at Mar. 31, 2022	462,235		$ 11	2,259,906		(2,059)	(1,795,623)
Beginning balance, Shares at Mar. 31, 2022			106,440,000
Issuance of common stock upon exercise of stock options	4,770			4,770
Issuance of common stock upon exercise of stock options, shares			283,000
Vesting of restricted stock units, net of shares withheld for taxes	(536)			(536)
Vesting of restricted stock units, net of shares withheld for taxes. shares			26,000
Share-based compensation expense	22,530			22,530
Issuance of common stock to employee stock purchase plan	2,531			2,531
Issuance of common stock to employee stock purchase plan, shares			92,000
Unrealized gain (loss) on available-for-sale investments	(766)					(766)
Net loss	(155,977)						(155,977)
Foreign currency gain (loss)	(369)					(369)
Ending balance at Jun. 30, 2022	$ 334,418		$ 11	$ 2,289,201		$ (3,194)	$ (1,951,600)
Ending balance, Shares at Jun. 30, 2022			106,841,000