COMMITMENTS AND CONTINGENCIES - LEASES (Details) $ in Thousands	1 Months Ended	3 Months Ended	12 Months Ended
	Apr. 30, 2012 ft²	Jun. 30, 2014	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Future minimum payments under operating leases for facilities
2018			$ 2,140
2019			2,096
2020			1,990
2021			1,752
2022			1,572
Total			9,550
Enterprise FM Trust
Future minimum payments under operating leases for facilities
Total			1,500
Enterprise FM Trust | Minimum
Future minimum payments under operating leases for facilities
Lessee Leasing Arrangements, Operating Leases, Term of Contract		18 months
Enterprise FM Trust | Maximum
Future minimum payments under operating leases for facilities
Lessee Leasing Arrangements, Operating Leases, Term of Contract		36 months
Office and laboratory
Future minimum payments under operating leases for facilities
Rent expense			300	$ 600	$ 600
Lease of cars
Future minimum payments under operating leases for facilities
Rent expense			3,200	3,200	$ 2,200
New lease Newark
Future minimum payments under operating leases for facilities
Total			8,000
Square feet agreed to lease | ft²	52,500
Additional square feet obligated lease | ft²	8,000
Deferred rent			$ 1,400	$ 1,600