Note 4 - Fair Value Measurements - Change in Fair Value of Contingent Consideration Liability (Details) - Contingent Consideration Liability [Member] - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2017
Balance at beginning of period	$ 4,123
Contingent consideration liability established in connection with the acquisition of Ambrell		4,123
Fair value adjustment	(549)	(549)
Balance at end of period	$ 3,574	$ 3,574