CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional paid-in capital	Accumulated other comprehensive income	Accumulated deficit
Balance at beginning of period (shares) at Dec. 31, 2018		32,538,857
Balance at beginning of period at Dec. 31, 2018	$ 201,576	$ 33	$ 751,109	$ 9,479	$ (559,045)
Increase (Decrease) in Stockholders' Equity
Net loss	(213,256)				(213,256)
Issuance of common stock and warrants, net of issuance costs (shares)		4,269,838
Issuance of common stock, net of issuance costs	327,830	$ 4	327,826
Share-based compensation expense	55,537		55,537
Issuance of common stock from ESPP (shares)		14,488
Issuance of common stock from ESPP	675		675
Issuance of common stock under equity incentive plans (shares)		569,146
Issuance of common stock under equity incentive plans	8,473	$ 1	8,472
Proceeds from disgorgement of shareholders’ short-swing profits	1,050
Net exercise of warrants (shares)		2,125,000
Net exercise of warrants	0	$ 2	(2)
Unrealized gain (loss) on investments	410			410
Balance at end of period (shares) at Dec. 31, 2019		39,517,329
Balance at end of period at Dec. 31, 2019	382,295	$ 40	1,144,667	9,889	(772,301)
Increase (Decrease) in Stockholders' Equity
Net loss	(357,937)				(357,937)
Issuance of common stock and warrants, net of issuance costs (shares)		8,124,168
Issuance of common stock, net of issuance costs	1,203,617	$ 8	1,203,609
Share-based compensation expense	85,847		85,847
Issuance of common stock from ESPP (shares)		14,436
Issuance of common stock from ESPP	1,206		1,206
Issuance of common stock under equity incentive plans (shares)		1,319,901
Issuance of common stock under equity incentive plans	$ 45,891	$ 1	45,890
Net exercise of warrants (shares)	1,400,000	1,463,235
Net exercise of warrants	$ 0	$ 1	(1)
Unrealized gain (loss) on investments	$ (130)			(130)
Balance at end of period (shares) at Dec. 31, 2020	50,439,069	50,439,069
Balance at end of period at Dec. 31, 2020	$ 1,360,789	$ 50	2,481,218	9,759	(1,130,238)
Increase (Decrease) in Stockholders' Equity
Net loss	(581,784)				(581,784)
Issuance of common stock and warrants, net of issuance costs (shares)		3,448,275
Issuance of common stock, net of issuance costs	474,697	$ 3	474,694
Share-based compensation expense	113,502		113,502
Issuance of common stock from ESPP (shares)		20,672
Issuance of common stock from ESPP	2,567		2,567
Issuance of common stock under equity incentive plans (shares)		825,074
Issuance of common stock under equity incentive plans	$ 27,958	$ 1	27,957
Net exercise of warrants (shares)	623,814	623,814
Net exercise of warrants	$ 0	$ 1	(1)
Unrealized gain (loss) on investments	$ (691)			(691)
Balance at end of period (shares) at Dec. 31, 2021	55,356,904	55,356,904
Balance at end of period at Dec. 31, 2021	$ 1,397,038	$ 55	$ 3,099,937	$ 9,068	$ (1,712,022)