Commitments, Collaborations and Contingencies (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Commitments, Collaborations and Contingencies
Rent expense per year	$ 401,000
Rent expense under operating leases associated with new office leases	379,000	265,000	180,000
Future minimum lease payments
2013	410,000
2014	23,000
Total future minimum lease payments	$ 433,000