Accounts Payable and Accrued Expenses (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Accounts Payable and Accrued Expenses [Abstract]
Accrued consulting and clinical trial costs	$ 1,593	$ 2,672
Accrued payroll and related costs	875	2,123
Restructuring accrual	212	0
Legal and professional fees	880	608
Accounts payable	307	793
Other	114	316
Total	$ 3,981	$ 6,512