Note 4 - Leases - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Operating lease expense	$ 311	$ 299	$ 922	$ 890
Financing lease expense	8	8	24	24
Short Term lease expense	4	35	17	104
Total lease expense	$ 323	$ 342	$ 963	$ 1,018
Weighted Average Remaining Lease Term (Years) - operating leases (Year)	7 years 4 months 17 days	8 years 4 months 28 days	7 years 4 months 17 days	8 years 4 months 28 days
Weighted Average Remaining Lease Term (Years) - financing leases (Year)	2 years 3 months 29 days	3 years 29 days	2 years 3 months 29 days	3 years 29 days
Weighted Average Discount Rate - operating leases	3.23%	3.23%	3.23%	3.23%
Weighted Average Discount Rate - financing leases	5.00%	5.00%	5.00%	5.00%
Operating cash flows from operating leases			$ 980	$ 983
Operating cash flows from financing lease			4	4
Financing cash flows from financing lease			13	13
Right-of-use assets obtained in exchange for new operating lease liabilities			$ 121	$ 699