CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Statement Of Income And Comprehensive Income [Abstract]
Collaboration revenue	$ 2,702	$ 1,666
Operating expenses:
Research and development	100,392	89,398
General and administrative	32,573	22,211
Total operating expenses	132,965	111,609
Loss from operations	(130,263)	(109,943)
Other income:
Interest income	1,569	6,027
Total other income	1,569	6,027
Net loss	$ (128,694)	$ (103,916)
Net loss per share-basic and diluted	$ (2.80)	$ (2.47)
Weighted average common shares outstanding-basic and diluted	45,910,787	42,117,690