ACCOUNTS PAYABLE AND ACCRUED EXPENSES - Summary of accounts payable and accrued expenses (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Payables and Accruals [Abstract]
Accounts payable	$ 313	$ 186
Accrued payroll	1,288	1,956
Accrued outsourced pre-clinical and clinical fees	4,098	3,273
Accrued professional fees	307	516
Other accrued expenses	229	303
Accounts payable and accrued expenses, Total	$ 6,235	$ 6,234