Commitments and Contingencies - Facility Leases (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Schedule of Facility Leases [Line Items]
2015	$ 18,107,000
2016	18,497,000
2017	18,897,000
2018	19,307,000
2019	19,728,000
Thereafter	192,014,000
Total	286,550,000
Facility lease obligations [Abstract]
Interest expense in connection with facility lease obligation	14,500,000	16,200,000	16,000,000
Facilities - Buildings A and B and C
Schedule of Facility Leases [Line Items]
2015	13,545,000
2016	13,809,000
2017	14,079,000
2018	14,356,000
2019	14,640,000
Thereafter	132,027,000
Total	202,456,000
Facility lease obligations [Abstract]
Imputed interest rate applicable to facility lease obligation	11.00%
Facility lease obligation, including reimbursements	110,200,000	111,200,000
Facilities - Building C
Schedule of Facility Leases [Line Items]
2015	4,562,000
2016	4,688,000
2017	4,818,000
2018	4,951,000
2019	5,088,000
Thereafter	59,987,000
Total	84,094,000
Facility lease obligations [Abstract]
Imputed interest rate applicable to facility lease obligation	9.00%
Facility lease obligation, including reimbursements	49,300,000	49,100,000
Facilities Building D and E
Facility lease obligations [Abstract]
Facility lease obligation, including reimbursements	$ 152,800,000	$ 25,000,000