Income Taxes - Principal Components of Net Deferred Tax Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Deferred Tax Assets
Net operating loss carryforwards	$ 64,080	$ 59,314	$ 56,030
Tax credit carryforwards	11,953	10,752	9,888
Capitalized tax assets	118	138	155
Accruals	135	116	124
Stock compensation	5,898	5,883	5,487
Operating lease liability	314	384	728
IRC 174 capitalization	8,387	6,713	4,518
Other			21
Total deferred tax assets	90,885	83,300	76,951
Deferred Tax Liabilities
Operating lease right-of-use asset	(330)	(322)	(620)
Other	(22)
Valuation allowance	(90,533)	(82,978)	(76,331)
Net deferred tax assets	0	0	0
Period increase in DTA valuation allowance	$ 7,600	$ 6,600	$ 9,200