Commitments (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Commitments (Textual) [Abstract]
Total rental expense	$ 1,400,000	$ 1,400,000
Regents of University of California [Member]
Commitments (Textual) [Abstract]
Payment of non-refundable initial license fee	$ 10,000
Period for the payment of initial license fees	30 days
Massachusetts Institute of Technology [Member]
Commitments (Textual) [Abstract]
Agreement termination period	June 2015