Income Taxes - Components of Company's Deferred Tax Asset (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Deferred Tax Assets, Net of Valuation Allowance [Abstract]
Accrued bonuses	$ 63	$ 63
Accrued vacation	28	26
Net operating loss (NOL) carryover	15,818	14,975
Research & development tax credits	2,509	3,353
Share based expense	671	572
Other	3	4
Right of use lease liability	46	49
Fixed asset depreciation	44	43
Total deferred tax asset	19,182	19,085
Less: valuation allowance	(19,140)	(19,042)
Net deferred tax asset	42	43
Right of use asset	(42)	(43)
Net deferred tax asset	$ 0	$ 0