Note 5 - Leases - Leases Cost (Details) - USD ($) $ in Thousands		3 Months Ended				6 Months Ended
	Jan. 01, 2019	Jun. 30, 2020		Jun. 30, 2019		Jun. 30, 2020		Jun. 30, 2019		Dec. 31, 2019
Operating lease costs		$ 363		$ 332		$ 729		$ 637
Short-term and other lease costs		71		84		148		182
Total lease costs		434		416		877		819
Operating cash flows from operating leases		330		423		703		727
ROU assets obtained in exchange for new operating lease liabilities (1)	$ 2,200	$ 1,467	[1]	$ 317	[1]	$ 1,744	[1]	$ 2,581	[1]
Weighted-average remaining lease term (in years) (Year)		2 years 8 months 12 days				2 years 8 months 12 days				2 years 1 month 6 days
Weighted-average discount rate		3.00%				3.00%				3.70%

[1] For the six months ended June 30, 2019, the amount includes $2.2 million for operating leases existing on January 1, 2019.