Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Common Stock At The Market Offering	Additional Paid-in Capital	Additional Paid-in Capital At The Market Offering	Accumulated Other Comprehensive (Loss) Income	Accumulated Deficit
Beginning balance at Dec. 31, 2019	$ 290,781	$ 6		$ 1,108,516		$ 220	$ (817,961)
Beginning balance (in shares) at Dec. 31, 2019		56,806
Issuance of common stock and pre-funded warrants through underwritten offering, net of offering costs	353,588		$ 2		$ 353,586
Issuance of common stock and pre-funded warrants through underwritten offering, net of offering costs, shares			20,060
Issuance of common stock, net of commissions and offering costs, value	68,004			68,004
Issuance of common stock, net of commissions and offering costs, shares		4,786
Exercise of pre-funded warrants, shares		57
RSU settlements, net of shares withheld	(1,521)			(1,521)
RSU settlements, net of shares withheld, shares		1,112
Issuance of common stock pursuant to employee stock awards	6,680			6,680
Issuance of common stock pursuant to employee stock awards, shares		551
Stock-based compensation expense	51,351			51,351
Net loss	(306,620)						(306,620)
Unrealized (loss) gain on available-for-sale securities	76					76
Ending balance at Dec. 31, 2020	462,339	$ 8		1,586,616		296	(1,124,581)
Ending balance (in shares) at Dec. 31, 2020		83,372
Issuance of common stock, net of commissions and offering costs, value	98,697	$ 1		98,696
Issuance of common stock, net of commissions and offering costs, shares		6,241
RSU settlements, net of shares withheld	(1,244)			(1,244)
RSU settlements, net of shares withheld, shares		1,492
Issuance of common stock pursuant to employee stock awards	6,762			6,762
Issuance of common stock pursuant to employee stock awards, shares		566
Stock-based compensation expense	53,865			53,865
Net loss	(340,141)						(340,141)
Unrealized (loss) gain on available-for-sale securities	(664)					(664)
Ending balance at Dec. 31, 2021	279,614	$ 9		1,744,695		(368)	(1,464,722)
Ending balance (in shares) at Dec. 31, 2021		91,671
Issuance of common stock, net of commissions and offering costs, value	21,891			21,891
Issuance of common stock, net of commissions and offering costs, shares		1,619
RSU settlements, net of shares withheld	(623)	$ 1		(624)
RSU settlements, net of shares withheld, shares		2,204
Issuance of common stock pursuant to employee stock awards	1,921			1,921
Issuance of common stock pursuant to employee stock awards, shares		433
Stock-based compensation expense	53,838			53,838
Net loss	(228,302)						(228,302)
Unrealized (loss) gain on available-for-sale securities	(1,699)					(1,699)
Ending balance at Dec. 31, 2022	$ 126,640	$ 10		$ 1,821,721		$ (2,067)	$ (1,693,024)
Ending balance (in shares) at Dec. 31, 2022		95,927