PROPERTY AND EQUIPMENT (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 34,304	$ 33,547
Less - accumulated depreciation and amortization	(25,601)	(23,803)
Property, Plant and Equipment, Net	8,703	9,744
Depreciation	1,983	2,370	$ 3,140
Laboratory Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	16,265	15,493
Furniture And Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	2,342	2,244
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	15,678	15,635
Equipment Under Construction [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 19	$ 175