Note 14 - Segment Information - Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Net revenues	$ 30,272	$ 30,941	$ 94,087	$ 95,418
Identifiable Assets	158,367		158,367		$ 134,829
Earnings before income tax expense	569	2,723	1,652	9,482
Acquired intangible amortization	(944)	(515)	(2,436)	(1,582)
Interest expense	(219)	(168)	(612)	(526)
Other income	301	423	949	678
Operating Segments [Member]
Net revenues	30,272	30,941	94,087	95,418
Earnings before income tax expense	3,807	5,885	11,302	18,328
Segment Reporting, Reconciling Item, Corporate Nonsegment [Member]
Earnings before income tax expense	(2,376)	(2,902)	(7,551)	(7,416)
Electronic Test [Member]
Identifiable Assets	81,592		81,592		32,505
Electronic Test [Member] | Operating Segments [Member]
Net revenues	15,481	11,547	42,756	32,911
Earnings before income tax expense	2,311	3,268	5,867	8,487
Environmental Technologies [Member]
Identifiable Assets	21,335		21,335		16,772
Environmental Technologies [Member] | Operating Segments [Member]
Net revenues	6,734	7,000	21,835	23,178
Earnings before income tax expense	426	523	1,434	2,479
Process Technologies [Member]
Identifiable Assets	53,596		53,596		56,842
Process Technologies [Member] | Operating Segments [Member]
Net revenues	8,057	12,394	29,496	39,329
Earnings before income tax expense	1,070	$ 2,094	4,001	$ 7,362
Corporate Segment [Member]
Identifiable Assets	$ 1,844		$ 1,844		$ 28,710