GEOGRAPHIC AND SEGMENT INFORMATION - Reportable Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Sales	$ 44,510	$ 48,517
(Loss) income from operations	(23,562)	(14,448)
Interest income	157	11
Interest expense	(15)	(10)
Other income (losses), net	509	(373)
Income tax expense	367	380
Operating Segments | Advanced Energy
Segment Reporting Information [Line Items]
Sales	36,803	42,985
(Loss) income from operations	(4,103)	2,784
Interest expense	0
Income tax expense	0	0
Operating Segments | OEM
Segment Reporting Information [Line Items]
Sales	7,707	5,532
(Loss) income from operations	1,641	1,033
Income tax expense	0	0
Corporate (Other)
Segment Reporting Information [Line Items]
(Loss) income from operations	(21,100)	(18,265)
Interest income	157	11
Interest expense	(15)	(10)
Other income (losses), net	509	(373)
Income tax expense	$ 367	$ 380