PROPERTY AND EQUIPMENT (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 54,471		$ 54,060
Less accumulated depreciation	(38,960)		(38,079)
Total property and equipment, net	15,511		15,981
Depreciation and amortization	1,000	$ 1,100
Operating leases, gross	11,000		10,800
Operating leases, accumulated depreciation	6,400		6,100
Land
Property, Plant and Equipment [Line Items]
Property and equipment, gross	377		377
Building
Property, Plant and Equipment [Line Items]
Property and equipment, gross	2,978		2,978
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	33,591		33,087
Office furniture and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,767		1,687
Computer hardware and software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	4,725		4,704
Leasehold and building improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	10,086		9,953
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 947		$ 1,274
Machinery and equipment | Minimum
Property, Plant and Equipment [Line Items]
Property plant and equipment, useful life	5 years
Machinery and equipment | Maximum
Property, Plant and Equipment [Line Items]
Property plant and equipment, useful life	7 years