Commitments and Contingencies - Facility Leases (Details) (USD $)	12 Months Ended				24 Months Ended		12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Facilities - Buildings A and B	Dec. 31, 2010 Facilities - Buildings A and B	Dec. 31, 2010 Facilities - Buildings A and B	Dec. 31, 2011 Facilities - Buildings A and B	Dec. 31, 2012 Facilities - Building C	Dec. 31, 2010 Facilities - Building C	Dec. 31, 2011 Facilities - Building C
Facility lease obligations [Abstract]
Capitalized costs of constructing the new facility				$ 58,400,000	$ 58,400,000			$ 27,800,000
Reimbursements recognized as additional facility lease obligation					56,900,000			14,200,000
Imputed interest rate applicable to facility lease obligation			11.00%				9.00%
Interest expense in connection with facility lease obligation	16,000,000	15,600,000		9,100,000
Facility lease obligation, including reimbursements			112,000,000			113,000,000	48,800,000		47,500,000
Commitments under facility leases [Abstract]
2013	17,462,000		13,092,000				4,370,000
2014	17,833,000		13,343,000				4,490,000
2015	18,214,000		13,600,000				4,614,000
2016	18,604,000		13,864,000				4,740,000
2017	19,004,000		14,134,000				4,870,000
Thereafter	133,935,000		98,906,000				35,029,000
Total	$ 225,052,000		$ 166,939,000				$ 58,113,000