ACCOUNTS PAYABLE AND ACCRUED EXPENSES - Summary (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Payables and Accruals [Abstract]
Accounts payable	$ 163	$ 560
Accrued payroll	1,334	2,872
Accrued outsourced pre-clinical and clinical fees	4,877	5,501
Accrued professional fees	418	641
Other accrued expenses	690	589
Accounts payable and accrued expenses, Total	$ 7,482	$ 10,163