SEGMENT INFORMATION - Segment Reporting Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024
Segment Reporting Information [Line Items]
Revenue	$ 26,637	$ 29,824
Cost of revenue	15,581	16,748
Other divisional costs	10,423	9,287
Division operating income (loss)	633	3,789
Amortization of acquired intangible assets	813	595
Restructuring costs	313	0
Corporate expenses	2,388	2,702
Operating (loss) income	(2,881)	492
Interest expense	(152)	(140)
Other income	244	435
(Loss) earnings before income tax expense	(2,789)	787
Depreciation	316	273
Amortization of deferred compensation related to stock-based awards	423	349
Capital expenditures	229	340
Total assets	148,027	159,527	$ 152,288
Corporate & Other
Segment Reporting Information [Line Items]
Amortization of acquired intangible assets	813	595
Restructuring costs	313
Corporate expenses	2,388	2,702
Operating (loss) income	(3,514)	(3,297)
Interest expense	(152)	(140)
Other income	244	435
(Loss) earnings before income tax expense	(3,422)	(3,002)
Depreciation	35	21
Amortization of deferred compensation related to stock-based awards	349	276
Capital expenditures	7	5
Total assets	1,572	9,580
Electronic Test | Operating Segments
Segment Reporting Information [Line Items]
Revenue	13,259	11,116
Cost of revenue	7,313	5,546
Other divisional costs	5,265	3,757
Division operating income (loss)	681	1,813
Operating (loss) income	681	1,813
(Loss) earnings before income tax expense	681	1,813
Depreciation	154	88
Amortization of deferred compensation related to stock-based awards	54	53
Capital expenditures	134	36
Total assets	73,322	75,508
Environmental Technologies | Operating Segments
Segment Reporting Information [Line Items]
Revenue	6,268	6,828
Cost of revenue	4,163	4,533
Other divisional costs	2,360	2,280
Division operating income (loss)	(255)	15
Operating (loss) income	(255)	15
(Loss) earnings before income tax expense	(255)	15
Depreciation	65	64
Amortization of deferred compensation related to stock-based awards	(32)	38
Capital expenditures	82	229
Total assets	21,666	16,624
Process Technologies | Operating Segments
Segment Reporting Information [Line Items]
Revenue	7,110	11,880
Cost of revenue	4,105	6,669
Other divisional costs	2,798	3,250
Division operating income (loss)	207	1,961
Operating (loss) income	207	1,961
(Loss) earnings before income tax expense	207	1,961
Depreciation	62	100
Amortization of deferred compensation related to stock-based awards	52	(18)
Capital expenditures	6	70
Total assets	$ 51,467	$ 57,815