ACCRUED EXPENSES (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
ACCRUED EXPENSES.
Accrued Payroll and Employee Benefits	$ 5,601	$ 4,284
Accrued Research and Development Contract Costs	14,548	12,696
Accrued Professional Fees	399	490
Other Accrued Expenses	3,768	1,826
Accrued Expenses	$ 24,316	$ 19,296