Commitments and Contingencies - Leases (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Loss Contingencies [Line Items]
Rent expense under operating leases	$ 4,100,000	$ 3,200,000	$ 1,900,000
Future Minimum Lease Payments under Non-cancelable Capital Leases
2014	943,000
2015	217,000
2016	4,000
2017	0
2018	0
Thereafter	0
Total minimum lease payments	1,164,000
Less: Amounts representing interest	(41,000)
Present value of capital lease obligations	1,123,000
Less: Current portion	(905,000)	(1,643,000)
Long-term portion of capital lease obligations	218,000	1,227,000
Building lease and other commitments
Future Minimum Lease Payments under Non-cancelable Operating Leases
2014	4,938,000
2015	5,042,000
2016	5,365,000
2017	5,511,000
2018	5,512,000
Thereafter	410,000
Total minimum lease payments	$ 26,778,000