ACCOUNTS PAYABLE AND ACCRUED EXPENSES - Summary of accounts payable and accrued expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Payables and Accruals [Abstract]
Accounts payable	$ 357	$ 186
Accrued payroll	914	1,956
Accrued outsourced pre-clinical and clinical fees	3,644	3,273
Accrued professional fees	247	516
Other accrued expenses	229	303
Accounts payable and accrued expenses, Total	$ 5,391	$ 6,234