Note 17 - Segment Information - Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2024	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2024	Dec. 31, 2023
Revenue	$ 36,603	$ 30,272	$ 33,991	$ 29,824	$ 27,884	$ 30,941	$ 32,558	$ 31,919	$ 130,690	$ 123,302
Cost of revenue									75,266	66,324
Division operating income									3,394	10,439
Acquired intangible amortization									2,545	2,094
Corporate expenses									9,881	10,273
Interest expense									(846)	(679)
Other income									906	1,288
Earnings before income tax expense	1,802	$ 569	$ 296	$ 787	1,566	$ 2,723	$ 3,365	$ 3,394	3,454	11,048
Depreciation									1,399	1,022
Stock-based compensation									1,857	2,047
Capital expenditures									1,324	1,291
Total assets	152,288				134,829				152,288	134,829
Operating Segments [Member]
Revenue									130,690	123,302
Cost of revenue									75,266	66,324
Other divisional costs									39,604	34,172
Division operating income									15,820	22,806
Operating Segments [Member] | Electronic Test [Member]
Revenue									63,878	41,016
Cost of revenue									35,843	18,076
Other divisional costs									19,303	12,751
Division operating income									8,732	10,189
Interest expense									0	0
Other income									0	0
Earnings before income tax expense									8,732	10,189
Depreciation									596	283
Stock-based compensation									217	150
Capital expenditures									347	599
Total assets	75,671				32,505				75,671	32,505
Operating Segments [Member] | Environmental Technologies [Member]
Revenue									28,898	30,801
Cost of revenue									17,780	18,631
Other divisional costs									9,002	9,097
Division operating income									2,116	3,073
Interest expense									0	0
Other income									0	0
Earnings before income tax expense									2,116	3,073
Depreciation									301	251
Stock-based compensation									182	85
Capital expenditures									561	495
Total assets	21,163				16,772				21,163	16,772
Operating Segments [Member] | Process Technologies [Member]
Revenue									37,914	51,485
Cost of revenue									21,643	29,617
Other divisional costs									11,299	12,324
Division operating income									4,972	9,544
Interest expense									0	0
Other income									0	0
Earnings before income tax expense									4,972	9,544
Depreciation									387	399
Stock-based compensation									140	209
Capital expenditures									176	170
Total assets	50,921				56,842				50,921	56,842
Segment Reporting, Reconciling Item, Corporate Nonsegment [Member]
Division operating income									(12,426)	(12,367)
Acquired intangible amortization									2,545	2,094
Corporate expenses									9,881	10,273
Interest expense									(846)	(679)
Other income									906	1,288
Earnings before income tax expense									(12,366)	(11,758)
Depreciation									115	89
Stock-based compensation									1,318	1,603
Capital expenditures									240	27
Total assets	$ 4,533				$ 28,710				$ 4,533	$ 28,710