Note 5 - Leases - Lease Cost and Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Operating lease cost	$ 59,000	$ 102,000	$ 265,000	$ 303,000
Sublease income	(30,000)	(43,000)	(129,000)	(129,000)
Total lease cost	29,000	59,000	136,000	174,000
Cash paid for amounts included in the measurement of lease liabilities - Operating leases	$ 59,000	$ 102,000	$ 265,000	$ 303,000
Weighted-average remaining lease term - Operating leases in years (Year)	10 months 20 days	1 year 3 months 18 days	10 months 20 days	1 year 3 months 18 days
Weighted-average discount rate - Operating leases	4.99%	5.71%	4.99%	5.71%