Note 3 - Income Taxes - Deferred Income Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Net operating loss carry forwards	$ 7,734	$ 7,675
Engineering credit carry forwards	1,920	1,919
Inventory reserves	503	558
Capital loss and other credit carry forwards	6
Allowance for bad debts and returns	13	16
Stock compensation	330	287
Capitalized inventory costs, stock compensation and other accuals	389	233
Total gross deferred tax assets	10,895	10,688
Less valuation allowance on deferred tax assets	(10,686)	(10,688)
Net deferred tax assets	209
Deferred tax liabilities:
Depreciation and other
Right to use property	(179)
Total deferred tax liabilities	(179)
Net deferred taxes	$ 30