Note 15 - Segment Information - Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Net revenues	$ 24,081	$ 19,556
Earnings before income tax expense	655	2,578
Acquired intangible amortization	(782)	(304)
Other income (expense)	(147)	(2)
Operating Segments [Member]
Net revenues	24,081	19,556
Earnings before income tax expense	3,419	4,366
Operating Segments [Member] | Electronic Test [Member]
Net revenues	8,778	8,501
Earnings before income tax expense	1,887	2,987
Operating Segments [Member] | Environmental Technologies [Member]
Net revenues	6,993	6,198
Earnings before income tax expense	802	923
Operating Segments [Member] | Process Technologies [Member]
Net revenues	8,310	4,857
Earnings before income tax expense	730	456
Corporate, Non-Segment [Member]
Earnings before income tax expense	$ (1,835)	$ (1,482)