Income Taxes - Deferred tax assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Deferred tax assets
Net operating loss carryforwards	$ 80,136	$ 75,849
Tax credit carryforwards	12,073	10,063
Capitalized research and development	8,094	139
Capitalized legal expenses	964	1,048
Lease liability	257	99
Other differences	2,365	1,977
Total gross deferred tax assets	103,889	89,175
Less valuation allowance	(103,630)	(89,068)
Net deferred tax assets	259	107
Deferred tax liabilities
ROU asset	(259)	(107)
Net deferred taxes	0	0
Deferred tax assets research and development	8,100
Increase in valuation allowance	$ 14,600	$ 11,200