Accrued Expenses (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Accrued Expenses
Employee compensation and benefits	$ 2,595	$ 2,379
Commercial manufacturing	815	229
Professional services	578	301
Other	904	610
Total accrued expenses	$ 4,892	$ 3,519