Income Taxes Income Tax Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Expected income tax benefit	$ (1,997)	$ (1,393)	$ (697)
State income taxes, net of federal tax effect	(168)	(219)	455
Effect of deferred rate change	0	0	8
Foreign tax	76	27	38
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Payment Arrangement, Amount	258	15	13
Non-deductible stock issuance costs	(82)	3	85
Federal R&D credit	(67)	(54)	(32)
Effective Income Tax Rate Reconciliation, Tax Credit, Other, Amount	0	0	(12)
Foreign unremitted earnings	0	0	130
Change in valuation allowance	1,655	1,379	408
Other, net	19	48	(98)
Income tax expense (benefit)	$ (306)	$ (194)	$ 298