Commitments and Contingencies (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Future minimum lease payments under non-cancelable operating leases
2013	$ 3,378,000
2014	3,286,000
2015	3,264,000
2016	3,031,000
2017	2,751,000
Thereafter	2,424,000
Total	18,134,000
Total rent expense	3,600,000	4,600,000	2,700,000
Future milestone payments under Assignment and License Agreements
2013	1,280,000
2014	2,010,000
2016	5,910,000
2017	10,074,000
Thereafter	8,593,000
Total	$ 27,867,000