GEOGRAPHIC AND SEGMENT INFORMATION - REPORTABLE SEGMENT (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Sales	$ 5,629	$ 3,397
Operating income (loss)	(5,730)	(2,720)
Interest income	423	0
Interest expense	0	(34)
Other losses	(295)	0
Change in value of derivative liabilities	0	(26)
Income tax expense	(6)	(11)
Operating Segments | Advanced Energy
Segment Reporting Information [Line Items]
Sales	4,371	2,629
Operating income (loss)	(3,328)	(578)
Interest income	0
Interest expense		0
Other losses	0
Change in value of derivative liabilities		0
Income tax expense	0	0
Operating Segments | OEM
Segment Reporting Information [Line Items]
Sales	1,258	768
Operating income (loss)	591	406
Interest income	0
Interest expense		0
Other losses	0
Change in value of derivative liabilities		0
Income tax expense	0	0
Corporate (Other)
Segment Reporting Information [Line Items]
Sales	0	0
Operating income (loss)	(2,993)	(2,548)
Interest income	423
Interest expense		(34)
Other losses	(295)
Change in value of derivative liabilities		(26)
Income tax expense	$ (6)	$ (11)