Condensed Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Income Statement [Abstract]
Revenue	$ 25,205
Operating expenses:
Research and development	41,263	$ 22,769
General and administrative	19,991	39,857
Total operating expenses	61,254	62,626
Loss from operations	(36,049)	(62,626)
Other income, net	545	1,908
Net loss	(35,504)	(60,718)
Unrealized loss on marketable securities	(186)	(316)
Comprehensive loss	$ (35,690)	$ (61,034)
Net loss per share, basic and diluted	$ (0.73)	$ (1.69)
Weighted-average common shares outstanding, basic and diluted	48,920,403	35,919,358