Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Revenue:
Collaboration revenue - related party	$ 1,216	$ 5,263	$ 2,709	$ 9,911
Type of Revenue [Extensible List]	us-gaap:LicenseAndServiceMember	us-gaap:LicenseAndServiceMember	us-gaap:LicenseAndServiceMember	us-gaap:LicenseAndServiceMember
Grant revenue	$ 0	$ 0	$ 0	$ 1,070
Total revenue	1,216	5,263	2,709	10,981
Operating expenses:
Research and development expenses	43,935	35,954	83,584	65,257
General and administrative expenses	20,335	17,451	38,906	29,192
Collaboration (profit) loss sharing - related party	271	0	(705)	0
Total operating expenses	64,541	53,405	121,785	94,449
Loss from operations	(63,325)	(48,142)	(119,076)	(83,468)
Other (expense) income:
Interest income	395	829	779	1,795
Interest expense	(1,501)	(732)	(2,413)	(1,428)
Other expense	(304)	(285)	(649)	(694)
Total other (expense) income, net	(1,410)	(188)	(2,283)	(327)
Net loss	$ (64,735)	$ (48,330)	$ (121,359)	$ (83,795)
Net loss per share attributable to common stockholders, basic	$ (0.70)	$ (0.53)	$ (1.32)	$ (0.91)
Net loss per share attributable to common stockholders, diluted	$ (0.70)	$ (0.53)	$ (1.32)	$ (0.91)
Weighted average common shares outstanding, basic	92,255,416	91,659,829	92,224,382	91,593,845
Weighted average common shares outstanding, diluted	92,255,416	91,659,829	92,224,382	91,593,845
Other comprehensive income (loss):
Unrealized (loss) gain on investments, net of tax of $0	$ (41)	$ 27	$ (196)	$ 59
Total other comprehensive (loss) income	(41)	27	(196)	59
Comprehensive loss	$ (64,776)	$ (48,303)	$ (121,555)	$ (83,736)