Note 6 - Leases - Lease Cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Weighted-average remaining lease term (Year)	4 years 8 months 26 days		4 years 8 months 26 days
Weighted-average discount rate	6.15%		6.15%
Operating lease cost	$ 444	$ 447	$ 1,335	$ 1,349
Cash paid for amounts included in the measurement of lease liabilities	$ 440	$ 433	$ 1,313	$ 1,274