Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenue:
Collaboration revenue - related party	$ 4,648	$ 5,462
Type of Revenue [Extensible List]	us-gaap:LicenseAndServiceMember	us-gaap:LicenseAndServiceMember
Grant revenue	$ 1,070	$ 739
Collaboration revenue		1,988
Total revenue	5,718	8,189
Operating expenses:
Research and development expenses	29,303	21,743
General and administrative expenses	11,741	6,138
Total operating expenses	41,044	27,881
Loss from operations	(35,326)	(19,692)
Other (expense) income:
Interest income	966	159
Interest expense	(696)	(716)
Other (expense) income	(409)	368
Total other (expense) income, net	(139)	(189)
Net loss	$ (35,465)	$ (19,881)
Net loss per share attributable to common stockholders, basic and diluted	$ (0.39)	$ (0.28)
Weighted average common shares outstanding, basic and diluted	91,527,800	70,821,514
Net loss	$ (35,465)	$ (19,881)
Other comprehensive income (loss):
Unrealized gain (loss) on investments, net of tax of $0	32	(10)
Total other comprehensive income (loss)	32	(10)
Comprehensive loss	$ (35,433)	$ (19,891)