GEOGRAPHIC AND SEGMENT INFORMATION - REPORTABLE SEGMENT (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting Information [Line Items]
Sales	$ 6,568		$ 3,691	$ 12,391	$ 7,088
Income (loss) from continuing operations	(4,465)	$ (5,200)	(2,933)	(9,668)	(5,653)
Interest income	403		0	826	0
Interest expense	0		(38)	0	(72)
Other losses	(200)		0	(225)	0
Change in value of derivative liabilities	0		46	0	20
Income tax expense (benefit)	76		13	(48)	24
Operating Segments | Advanced Energy
Segment Reporting Information [Line Items]
Sales	5,269		3,113	9,640	5,742
Income (loss) from continuing operations	(1,011)	(3,400)	(792)	(4,399)	(1,370)
Interest income	0			0
Interest expense			0		0
Other losses	0			0
Change in value of derivative liabilities			0		0
Income tax expense (benefit)	0		0	0	0
Operating Segments | OEM
Segment Reporting Information [Line Items]
Sales	1,299		578	2,751	1,346
Income (loss) from continuing operations	136	800	302	921	708
Interest income	0			0
Interest expense			0		0
Other losses	0			0
Change in value of derivative liabilities			0		0
Income tax expense (benefit)	0		0	0	0
Corporate & Other
Segment Reporting Information [Line Items]
Sales	0		0	0	0
Income (loss) from continuing operations	(3,590)	$ (2,600)	(2,443)	(6,190)	(4,991)
Interest income	403			826
Interest expense			(38)		(72)
Other losses	(200)			(225)
Change in value of derivative liabilities			46		20
Income tax expense (benefit)	$ 76		$ 13	$ (48)	$ 24