CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating expenses:
Research and development	$ 24,468	$ 29,115	$ 31,830
General and administrative	8,097	9,515	11,930
Total operating expenses	32,565	38,630	43,760
Loss from operations	(32,565)	(38,630)	(43,760)
Interest income and other expense, net	654	(15)	540
Gain on sale of property and equipment	22
Gain on deconsolidation of Angel Pharmaceuticals			37,459
Sublease income - related party	587	235
Loss from equity method investment	(10,005)	(4,831)	(234)
Net loss	$ (41,307)	$ (43,241)	$ (5,995)
Net loss per share, basic	$ (0.89)	$ (1.03)	$ (0.20)
Net loss per share, diluted	$ (0.89)	$ (1.03)	$ (0.20)
Shares used to compute net loss per share, basic	46,553,511	41,854,110	29,478,878
Shares used to compute net loss per share, diluted	46,553,511	41,854,110	29,478,878
Other comprehensive loss:
Unrealized gain (loss) on marketable securities	$ (48)	$ (7)	$ (25)
Cumulative foreign currency translation adjustment	(2,384)	1,872
Comprehensive loss	$ (43,739)	$ (41,376)	$ (6,020)