Note 5 - Income Taxes (Details Textual) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($)
Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards	$ 0
Tax Credit Carryforward, Amount	0
State and Local Jurisdiction [Member]
Operating Loss Carryforwards	1,300
Operating Loss Carryforwards, Subject to Expiration	1,200
Operating Loss Carryforwards, Not Subject to Expiration	100
State and Local Jurisdiction [Member] | California Franchise Tax Board [Member]
Tax Credit Carryforward, Amount	$ 1,400
Effective Income Tax Rate Reconciliation, Tax Credit, Percent, Total	12.00%
Effective Income Tax Rate Reconciliation, Tax Credit, Research, Percent	8.30%