Accounts Payable and Accrued Expenses (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Accounts Payable and Accrued Expenses
Accrued research payables	$ 59,165	$ 52,015
Accrued compensation and benefits	45,795	47,622
Accrued rent	19,516	19,938
Trade payables	20,153	15,222
Deferred revenue	13,323	12,533
Deferred compensation	4,081	4,552
Accrued restructuring	2,411	3,768
Accrued transaction processing	3,001	2,972
Other	18,700	17,309
Total	$ 186,145	$ 175,931