Note 7 - Income Taxes (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Tax Credit Carryforward, Amount	$ 2,300
Period Of Increase In Ownership (Year)	3 years
Unrecognized Tax Benefits, Ending Balance	$ 0	$ 0
Domestic Tax Authority [Member]
Operating Loss Carryforwards	73,700
Operating Loss Carryforwards Subject to Expiration	50,900
Operating Loss Carry Forwards Indefinite	22,800
Foreign Tax Authority [Member]
Operating Loss Carryforwards	$ 14,100