Note 7 - Income Taxes - Reconciliation of the Income Tax Benefit to the Statutory Federal Income Tax Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Expected federal income tax benefit at 21%	$ (6,560)	$ (7,940)
Increase (decrease) in valuation allowance	(8,530)	3,617
State income tax	10	7
Expiring carryforwards	14,260	1,547
Non-deductible expenses and other	830	2,776
Income tax expense	$ 10	$ 7