Note 6 - Summary of Quantitative Attributes of Operating Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Lease cost
Operating lease cost	$ 618	$ 609
Total lease cost	618	609
Cash paid for amounts included in the measurement of lease liabilities:
Cashflows from operating leases	626	620	$ 631
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 369	$ 43	$ 698
Weighted average remaining lease terms:
Operating leases	13 years 1 month 6 days	13 years 9 months 18 days
Weighted average discount rates:
Operating leases	2.90%	2.78%