Note 10 - Income Taxes (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2021
Operating Loss Carryforwards, Total		$ 18,400
Deferred Tax Assets, Operating Loss Carryforwards, Total	$ 10,880	8,732
Deferred Tax Assets, Tax Credit Carryforwards, Other		7,500
Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax		1,000
Income Taxes Receivable	$ 19,500	41,100
Domestic Tax Authority [Member]
Deferred Tax Assets, Operating Loss Carryforwards, Total		3,870
Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member]
Open Tax Year	2017 2018 2019 2020 2021
State and Local Jurisdiction [Member] | California Franchise Tax Board [Member]
Operating Loss Carryforwards, Total		45,900
Deferred Tax Assets, Operating Loss Carryforwards, Total		$ 4,500