Note 13 - Commitments and Contingencies (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Leases, Rent Expense, Net	$ 1,500	$ 1,700	$ 1,800
Indemnification Agreement [Member]
Loss Contingency Accrual	$ 0	$ 0	$ 0