4. PROPERTY, PLANT AND EQUIPMENT (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 14,525	$ 20,033
Less: Accumulated depreciation and amortization	(11,921)	(12,069)
Property, plant and equipment, net	2,604	7,964
Building and improvements [Member]
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 285	285
Range of Asset Lives	7 to 36 years
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 906	896
Range of Asset Lives	2 to 5 years
Equipment [Member]
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 12,343	17,887
Range of Asset Lives	2 to 30 years
Furniture, computers and office equipment [Member]
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 907	901
Range of Asset Lives	2 to 8 years
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 84	$ 64