Note 3 - Acquisition - Purchase Price (Details) - USD ($) $ in Thousands		9 Months Ended
	May 24, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Goodwill, Ending Balance		$ 13,738		$ 13,738
Ambrell [Member]
Cash paid to acquire the capital stock of Ambrell	$ 22,610
Estimated fair value of contingent consideration	4,123		$ 4,123
Total purchase price	26,733
Goodwill, Ending Balance	12,032
Identifiable intangible assets	16,300
Cash	648
Trade accounts receivable	3,621
Inventories	1,917
Other current assets	200
Property and equipment	614
Accounts payable	(1,420)
Accrued expenses	(1,280)
Customer advances	(554)
Deferred tax liability	(5,345)
Total purchase price	$ 26,733