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, 2020	Dec. 31, 2019
Expected federal income tax benefit at 21%	$ (7,940)	$ (6,200)
Loss with no tax benefit provided	3,617	2,508
State income tax	7	6
Expiring carryforwards	1,547	2,427
Non-deductible expenses and other	2,776	1,265
Income tax expense	$ 7	$ 6