CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Statement Of Income And Comprehensive Income [Abstract]
Collaboration revenue	$ 29,305	$ 588
Operating expenses:
Research and development	21,755	29,310
General and administrative	8,661	7,770
Total operating expenses	30,416	37,080
Loss from operations	(1,111)	(36,492)
Other income:
Interest income	38	1,161
Total other income	38	1,161
Net loss	$ (1,073)	$ (35,331)
Net loss per share-basic and diluted	$ (0.02)	$ (0.78)
Weighted-average common shares outstanding-basic and diluted	50,363,579	45,151,265