Note 13 - Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Operating lease liabilities	$ 1,407	$ 1,601
Inventories	387	321
Accrued vacation pay and stock-based compensation	354	252
Net operating loss (state and foreign)	205	241
Allowance for doubtful accounts	45	44
Accrued warranty	31	13
Acquisition costs	9	10
Tax credit carryforwards	17	5
Other	49	71
Total	2,504	2,558
Valuation allowance	(64)	(169)
Deferred tax assets	2,440	2,389
Deferred tax liabilities:
Net intangible assets	(2,381)	(2,697)
Right-of-use assets	(1,245)	(1,400)
Depreciation of property and equipment	(193)	(214)
Deferred tax liabilities	(3,819)	(4,311)
Net deferred tax liabilities	$ (1,379)	$ (1,922)