Note 7 - Leases - Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Operating lease cost	$ 370	$ 307	$ 1,106	$ 1,142
Short-term lease cost	$ 12	$ 14	$ 39	$ 41
Weighted average remaining lease term (in years) (Year)	5 years 219 days		5 years 219 days
Weighted average discount rate	5.00%		5.00%
Minimum [Member]
Range of remaining lease terms (in years) (Year)			1 year 36 days
Maximum [Member]
Range of remaining lease terms (in years) (Year)			8 years 255 days