Note 3 - Acquisition (Details Textual) - USD ($) $ in Thousands		3 Months Ended		4 Months Ended	9 Months Ended
	May 24, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2017	Sep. 30, 2016
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability		$ (549)	$ 0		$ (549)
Ambrell [Member]
Payments to Acquire Businesses, Gross	$ 22,610
Business Acquisition, Transaction Costs	880
Business Combination, Consideration Transferred	26,733
Business Combination, Contingent Consideration, Liability	4,123
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual				$ 6,925
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual				$ 336
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability		$ (549)
Ambrell [Member] | Aggregate Total Payout [Member]
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High	$ 18,000