Note 16 - Segment Information - Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Net revenues	$ 29,571	$ 21,820	$ 53,652	$ 41,376
Earnings before income tax expense	2,570	3,056	3,225	5,634
Acquired intangible amortization	(765)	(305)	(1,547)	(609)
Other income (expense)	(158)	21	(305)	19
Operating Segments [Member]
Net revenues	29,571	21,820	53,652	41,376
Earnings before income tax expense	5,832	5,511	9,251	9,877
Operating Segments [Member] | Electronic Test [Member]
Net revenues	9,797	9,054	18,575	17,555
Earnings before income tax expense	2,193	3,237	4,080	6,224
Operating Segments [Member] | Environmental Technologies [Member]
Net revenues	7,507	6,647	14,500	12,845
Earnings before income tax expense	1,070	1,113	1,872	2,036
Operating Segments [Member] | Process Technologies [Member]
Net revenues	12,267	6,119	20,577	10,976
Earnings before income tax expense	2,569	1,161	3,299	1,617
Corporate, Non-Segment [Member]
Earnings before income tax expense	$ (2,339)	$ (2,171)	$ (4,174)	$ (3,653)