Note 8 - Leases - Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Operating lease cost	$ 393	$ 370	$ 1,174	$ 1,106
Short-term lease cost	$ 13	$ 12	$ 35	$ 39
Weighted average remaining lease term (in years) (Year)	6 years 219 days		6 years 219 days
Weighted average discount rate	4.40%		4.40%
Minimum [Member]
Range of remaining lease terms (in years) (Year)			109 days
Maximum [Member]
Range of remaining lease terms (in years) (Year)			10 years