Note 7 - Commitments and Contingencies - Lease Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Weighted-average remaining lease term (Year)	4 years 6 months 3 days	5 years 5 months 4 days
Weighted-average discount rate	6.20%	6.10%
Operating lease cost	$ 1,779	$ 1,796
Cash paid for amounts included in the measurement of lease liabilities	1,753	1,707
Right-of-use assets obtained in exchange for lease obligations	$ 0	$ 18