Income Taxes - Reconciliation of Effective Tax Rate to the Statutory Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Amount
Income tax benefit at federal statutory rate	$ (10,264)	$ (5,606)
State income tax, net of federal benefit	(2,185)	(1,979)
Other permanent differences	1	(185)
Research and development tax credits	(551)	(551)
Other tax credits	291	(555)
Tax reserve reassessment	157	(7)
Impact of CARES Act	0	(1,390)
Change in valuation allowance	12,361	6,348
Return adjustment	(278)	213
Stock-based compensation	74	104
Other, net	(12)	(105)
Total tax benefit	$ (406)	$ (3,713)
Percent
Income tax benefit at federal statutory rate	21.00%	21.00%
State income tax, net of federal benefit	4.50%	7.40%
Other permanent differences	0.00%	0.70%
Research and development tax credits	1.10%	2.10%
Other tax credits	(0.60%)	2.10%
Tax reserve reassessment	(0.30%)	0.00%
Impact of CARES Act	0.00%	5.20%
Change in valuation allowance	(25.30%)	(23.80%)
Return adjustment	0.60%	(0.80%)
Stock-based compensation	(0.20%)	(0.40%)
Other, net	0.00%	0.40%
Income tax benefit	0.80%	13.90%