Accrued Expenses (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Accrued Expenses [Abstract]
Accrued compensation	$ 1,206	$ 957
Accrued manufacturing	926	917
Accrued research and development	734	461
Accrued accounting and legal fees	428	315
Accrued sales and marketing	279	0
All other accrued expenses	586	322
Total accrued expenses	$ 4,159	$ 2,972