Note 10 - Income Taxes (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Operating Loss Carryforwards, Subject to Expiration	$ 59,809,000
Operating Loss Carryforwards, Not Subject to Expiration	$ 36,604,000
Open Tax Year	2017 2018 2019 2020 2021
Unrecognized Tax Benefits, Ending Balance	$ 0	$ 0
State and Local Jurisdiction [Member] | California Franchise Tax Board [Member]
Operating Loss Carryforwards, Total	$ 76,295,000