GEOGRAPHIC AND SEGMENT INFORMATION - REPORTABLE SEGMENT (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Sales	$ 3,672	$ 2,651	$ 10,760	$ 6,576
(Loss) income from operations	(2,796)	(2,833)	(8,449)	(10,648)
Interest income (expense), net	105	(36)	33	(103)
Change in fair value of derivative liabilities	0	(69)	20	57
Income tax (benefit) expense	(2,408)	6	(2,384)	15
Depreciation and amortization	58	171	429	527
Operating Segments | Advanced Energy
Segment Reporting Information [Line Items]
Sales	2,985	2,126	8,727	4,546
(Loss) income from operations	(1,155)	(718)	(2,525)	(3,821)
Interest income (expense), net	0	0	0	0
Change in fair value of derivative liabilities		0	0	0
Income tax (benefit) expense	0	0	0	0
Depreciation and amortization	0	0	0	0
Operating Segments | OEM
Segment Reporting Information [Line Items]
Sales	687	525	2,033	2,030
(Loss) income from operations	368	323	1,076	1,031
Interest income (expense), net	0	0	0	0
Change in fair value of derivative liabilities		0	0	0
Income tax (benefit) expense	0	0	0	0
Depreciation and amortization	0	0	0	0
Corporate (Other)
Segment Reporting Information [Line Items]
Sales	0	0	0	0
(Loss) income from operations	(2,009)	(2,438)	(7,000)	(7,858)
Interest income (expense), net	105	(36)	33	(103)
Change in fair value of derivative liabilities		(69)	20	57
Income tax (benefit) expense	(2,408)	6	(2,384)	15
Depreciation and amortization	$ 58	$ 171	$ 429	$ 527