Note 14 - Income Taxes - Significant Portions of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Net operating loss carryforwards	$ 19,754	$ 16,905
Contribution and other carryforwards	197	218
Inventory and accounts receivable reserves	668	549
Other	578	676
Valuation allowance	(20,281)	(17,662)
Deferred tax assets after valuation allowance	916	686
Deferred tax liabilities
Intangible assets	(2,765)	(2,914)
Property, plant and equipment	(73)	(186)
Total deferred tax liabilities	(2,838)	(3,100)
Net deferred tax liabilities	$ (1,922)	$ (2,414)