Accounts Payable and Accrued Expenses (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Accounts Payable and Accrued Expenses
Accrued research payables	$ 62,299	$ 52,015
Accrued compensation and benefits	35,523	47,622
Accrued rent	19,639	19,938
Trade payables	18,301	15,222
Deferred revenue	13,348	12,533
Deferred compensation	4,321	4,552
Accrued restructuring	3,071	3,768
Accrued transaction processing	2,779	2,972
Other	16,601	17,309
Total	$ 175,882	$ 175,931