Note 10 - Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Operating lease liabilities	$ 1,123
Net operating loss (state and foreign)	280	299
Inventories	247	212
Accrued vacation pay and stock-based compensation	279	184
Tax credit carryforwards	112	81
Allowance for doubtful accounts	44	46
Accrued warranty	19	20
Acquisition costs	12	13
Other	13	18
Total	2,129	873
Valuation allowance	(234)	(241)
Deferred tax assets	1,895	632
Deferred tax liabilities:
Net intangible assets	(2,923)	(3,167)
Right of use assets	(1,066)
Depreciation of property and equipment	(169)	(154)
Deferred tax liabilities	(4,158)	(3,321)
Net deferred tax liabilities	$ (2,263)	$ (2,689)