Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Revenue recognized	$ 0	$ 3,000	$ 0
Operating Expenses [Abstract]
Research and development	50,647	41,932	30,163
General and administrative	24,702	20,942	17,640
Goodwill impairment	9,758	0	0
Loss on transfer of nonfinancial assets	0	0	3,900
Total operating expenses	85,107	62,874	51,703
Loss from operations	(85,107)	(59,874)	(51,703)
Nonoperating Income (Expense) [Abstract]
Interest income	10	273	1,197
Interest expense	(3,642)	(2,688)	(2,147)
Change in fair value of preferred stock warrant liability	0	0	(288)
Change in fair value of derivative liability	(366)	(437)	183
Loss on extinguishment of debt	0	(162)	(566)
Other income	426	905	517
Total other expense, net	(3,572)	(2,109)	(1,104)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	(88,679)	(61,983)	(52,807)
Income Tax Expense (Benefit)	17	148	0
Net loss	(88,696)	(62,131)	(52,807)
Accruing dividends on Series A convertible preferred stock	0	0	(592)
Temporary Equity Repurchase Of Convertible Preferred Stock	(13,943)	0	0
Net loss attributable to common stockholders	$ (102,639)	$ (62,131)	$ (53,399)
Net loss per share attributable to common stockholders - basic and diluted (in dollars per share)	$ (3.99)	$ (3.09)	$ (4.63)
Weighted average shares of common stock outstanding - basic and diluted (in shares)	25,749	20,077	11,530
Currency translation adjustments	$ 0	$ 0	$ (119)
Total comprehensive loss	$ (88,696)	$ (62,131)	$ (52,926)