Commitments and Contingencies (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Future minimum lease payments under non-cancelable operating leases
2015	$ 3,839,000
2016	3,409,000
2017	3,271,000
2018	2,695,000
2019	643,000
Thereafter	128,000
Total	13,985,000
Total rent expense	3,600,000	3,500,000	3,600,000
Future milestone payments under Assignment and License Agreements
2015	2,311,000
2016	1,383,000
2017	1,339,000
2018	12,491,000
2019	2,568,000
Thereafter	7,777,000
Total	$ 27,869,000