Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue:
Total revenue	$ 135,082	$ 19,886	$ 13,469
Operating expenses:
Research and development	107,851	113,820	75,531
General and administrative	21,846	17,745	15,320
Total operating expenses	129,697	131,565	90,851
Operating income (loss)	5,385	(111,679)	(77,382)
Other income, net	2,334	4,490	2,980
Income (loss) before benefit from income taxes	7,719	(107,189)	(74,402)
Benefit from income taxes	691	816	389
Net income (loss)	$ 8,410	$ (106,373)	$ (74,013)
Net income (loss) per share:
Basic	$ 0.18	$ (2.49)	$ (2.06)
Diluted	$ 0.18	$ (2.49)	$ (2.06)
Weighted average shares:
Basic	47,413,250	42,669,333	35,892,786
Diluted	47,915,030	42,669,333	35,892,786
Other comprehensive income (loss), net of tax of $0:
Change in unrealized gains (losses) on available-for-sale marketable securities	$ (97)	$ 284	$ (44)
Total comprehensive income (loss)	8,313	(106,089)	(74,057)
License and Milestone Fees
Revenue:
Total revenue	134,439	19,746	13,436
Clinical Compound Revenue
Revenue:
Total revenue	$ 643	$ 140	$ 33