Note 13 - Segment Information - Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Net revenues	$ 31,919	$ 24,081
Earnings before income tax expense	3,394	655
Earnings before income tax expense	3,394	655
Acquired intangible amortization	(544)	(782)
Interest expense	182	137
Other income (expense)	58	(10)
Operating Segments [Member]
Net revenues	31,919	24,081
Earnings before income tax expense	6,267	3,419
Earnings before income tax expense	6,267	3,419
Operating Segments [Member] | Electronic Test [Member]
Net revenues	10,371	8,778
Earnings before income tax expense	2,578	1,887
Earnings before income tax expense	2,578	1,887
Operating Segments [Member] | Environmental Technologies [Member]
Net revenues	8,042	6,993
Earnings before income tax expense	1,013	802
Earnings before income tax expense	1,013	802
Operating Segments [Member] | Process Technologies [Member]
Net revenues	13,506	8,310
Earnings before income tax expense	2,676	730
Earnings before income tax expense	2,676	730
Corporate, Non-Segment [Member]
Earnings before income tax expense	(2,205)	(1,835)
Earnings before income tax expense	$ (2,205)	$ (1,835)