Note 5 - Income Taxes - Components of Net Deferred Tax Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred Tax Assets
Allowance for doubtful accounts	$ 21	$ 9
Accrued expenses	129	112
Stock-based compensation	325	265
R&D tax credits	1,083	1,005
Operating lease	944	1,130
PPP Loan expenses	0	9
NOL carryforward	219	97
Gross Deferred Tax Assets	2,721	2,627
Valuation Allowance	(414)	0
Deferred Tax Assets After Valuation Allowance	2,307	2,627
Deferred Tax Liabilities
Excess of tax over book depreciation and amortization	(1,249)	(1,775)
Prepaid expenses	(61)	(48)
Operating lease	(837)	(1,015)
Gross Deferred Tax Liabilities	(2,147)	(2,838)
Net Deferred Tax Assets/(Liabilities)	$ 160
Net Deferred Tax Assets/(Liabilities)		$ (211)