Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Income Statement [Abstract]
Collaboration revenue	$ 72,649	$ 16,319	$ 107,249	$ 20,974
Operating expenses:
Research and development	40,477	29,002	81,617	50,442
General and administrative	11,921	8,601	22,738	16,060
Change in fair value of contingent consideration	4,242	15,347	(39,737)	5,895
Total operating expenses	56,640	52,950	64,618	72,397
Income (loss) from operations	16,009	(36,631)	42,631	(51,423)
Other income, net	154	343	308	853
Income (loss) before income taxes	16,163	(36,288)	42,939	(50,570)
Income tax benefits	981	0	727	0
Net income (loss)	$ 17,144	$ (36,288)	$ 43,666	$ (50,570)
Net income (loss) per share—basic	$ 0.23	$ (0.58)	$ 0.58	$ (0.83)
Weighted average common shares outstanding—basic	75,254,186	62,282,291	75,222,119	61,145,254
Net income (loss) per share—diluted	$ 0.21	$ (0.58)	$ 0.55	$ (0.83)
Weighted average common shares outstanding—diluted	80,026,488	62,282,291	79,994,422	61,145,254