Note 1 - Business and Basis of Presentation (Details Textual) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Jan. 01, 2019	Dec. 31, 2018
Operating Lease, Expense	$ 400	$ 300
Operating Lease, Weighted Average Remaining Lease Term	5 years 333 days
Operating Lease, Right-of-Use Asset	$ 6,027
Operating Lease, Liability, Total	$ 6,192
Accounting Standards Update 2016-02 [Member]
Operating Lease, Right-of-Use Asset			$ 6,200
Operating Lease, Liability, Total			$ 6,200