Note 5 - Leases - Lease Cost and Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Operating lease cost	$ 103,000	$ 100,000
Sublease income	(50,000)	(43,000)
Total lease cost	53,000	57,000
Cash paid for amounts included in the measurement of lease liabilities - Operating leases	$ 103,000	$ 100,000
Weighted-average remaining lease term - Operating leases in years (Year)	11 months 12 days	1 year 9 months
Weighted-average discount rate - Operating leases	5.54%	5.78%