Note 5 - Leases - Lease Cost and Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Operating lease cost	$ 21,000	$ 103,000
Sublease income	0	(50,000)
Total lease cost	21,000	53,000
Cash paid for amounts included in the measurement of lease liabilities - Operating leases	$ 21,000	$ 103,000
Weighted-average remaining lease term - Operating leases in years (Year)	8 months 1 day	11 months 12 days
Weighted-average discount rate - Operating leases	4.42%	5.54%