Note 7 - Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Net operating loss carryforwards	$ 12,567	$ 12,481
Tax credit carryforwards	2,239	2,070
Intangible assets	1,412	1,352
Accrued expenses, reserves and other	1,996	2,176
Research and development	1,999	984
Total deferred tax assets	20,213	19,063
Valuation allowance for deferred tax assets	(2,697)	(1,942)
Net deferred tax assets	17,516	17,121
Property, plant and equipment	(79)	(262)
Intangible assets	8,219	5,538
Total deferred tax liabilities	(8,298)	(5,800)
Net deferred tax assets	$ 9,218	$ 11,321