Note 6 - Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Reserves and accruals	$ 603	$ 183
Amortization	60	53
Capital losses and other	12	13
Non-qualified stock option expense	2	194
Loss carryforwards	8,700	7,066
Total deferred tax assets	9,377	7,509
Valuation allowance	(7,649)	(4,757)
Net deferred tax assets	1,728	2,752
Depreciation	(2,001)	(2,752)
Total deferred tax liabilities	(2,001)	(2,752)
Net deferred tax liabilities	$ (273)	$ 0