Note 7 - Leases - Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating lease cost	$ 392	$ 366
Short-term lease cost	$ 12	$ 13
Weighted average remaining lease term (in years) (Year)	5 years 182 days
Weighted average discount rate	4.80%
Minimum [Member]
Range of remaining lease terms (in years) (Year)	292 days
Maximum [Member]
Range of remaining lease terms (in years) (Year)	8 years 36 days