Note 8 - Income Taxes (Details Textual) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	21.00%
Domestic Tax Authority [Member]
Operating Loss Carryforwards, Total	$ 71.7
Operating Loss Carryforwards that Do Not Expire	5.9
State and Local Jurisdiction [Member]
Operating Loss Carryforwards, Total	85.7
Operating Loss Carryforwards that Do Not Expire	$ 5.9