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	$ 2,308	$ 2,362	$ 2,252
Financial Grants in Support of Research and Development, Royalty Obligation	5.00%
Loss Contingency Accrual	$ 9,388