Note 18 - Quarterly Consolidated Financial Data (Unaudited) (Details Textual) - USD ($) $ in Thousands	3 Months Ended						12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2018	Dec. 31, 2017
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability	$ 2,828	$ 3,057	$ (710)	$ 1,726	$ 7,525	$ (549)	$ (5,744)	$ 1,621