Note 16 - Segment Information - Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Net revenues	$ 30,771	$ 21,144	$ 84,423	$ 62,520
Earnings before income tax expense	3,039	2,532	6,264	8,166
Acquired intangible amortization	(595)	(309)	(2,142)	(918)
Other income (expense)	(120)	(17)	(425)	2
Operating Segments [Member]
Net revenues	30,771	21,144	84,423	62,520
Earnings before income tax expense	5,892	4,802	15,143	14,679
Operating Segments [Member] | Electronic Test [Member]
Net revenues	10,408	8,103	28,983	25,658
Earnings before income tax expense	2,406	2,634	6,486	8,858
Operating Segments [Member] | Environmental Technologies [Member]
Net revenues	7,631	6,875	22,131	19,720
Earnings before income tax expense	1,021	1,090	2,893	3,126
Operating Segments [Member] | Process Technologies [Member]
Net revenues	12,732	6,166	33,309	17,142
Earnings before income tax expense	2,465	1,078	5,764	2,695
Corporate, Non-Segment [Member]
Earnings before income tax expense	$ (2,138)	$ (1,944)	$ (6,312)	$ (5,597)