Accrued Expenses (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Accrued Expenses [Abstract]
Accrued clinical trial expenses	$ 1,460	$ 675
Liability for stock based compensation awards	1,204	0
Accrued professional fees	185	110
Accrued interest payable	80	0
Other accrued expenses	4	15
Total accrued expenses	$ 2,933	$ 800