Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Revenue:
Total revenue	$ 94	$ 2,030	$ 2,705	$ 4,368
Costs and expenses:
Cost of product revenue	2	292	262	580
Research and development:
Noncash compensation	3,249	4,534	7,471	19,061
Other research and development	17,552	47,433	88,246	140,872
Total research and development	20,801	51,967	95,717	159,933
Selling, general and administrative:
Noncash compensation	3,740	9,463	663	27,857
Other selling, general and administrative	10,514	25,436	46,840	67,821
Total selling, general and administrative	14,254	34,899	47,503	95,678
Total costs and expenses	35,057	87,158	143,482	256,191
Operating loss	(34,963)	(85,128)	(140,777)	(251,823)
Other expense (income):
Interest expense	1,648	1,038	7,329	4,559
Other income	(793)	(529)	(2,765)	(1,619)
Total other expense (income), net	855	509	4,564	2,940
Net loss	$ (35,818)	$ (85,637)	$ (145,341)	$ (254,763)
Basic net loss per common share (in dollars per share)	$ (0.26)	$ (0.65)	$ (1.08)	$ (1.93)
Diluted net loss per common share (in dollars per share)	$ (0.26)	$ (0.65)	$ (1.08)	$ (1.93)
Weighted-average shares used in computing basic net loss per common share (in shares)	135,327,035	132,353,119	134,839,207	132,109,912
Weighted-average shares used in computing diluted net loss per common share (in shares)	135,327,035	132,353,119	134,839,207	132,109,912
Product revenue, net [Member]
Revenue:
Total revenue	$ 56	$ 1,992	$ 2,591	$ 4,254
License revenue [Member]
Revenue:
Total revenue	$ 38	$ 38	$ 114	$ 114