Accounts Payable and Accrued Expenses (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accounts Payable and Accrued Expenses
Accrued research payables	$ 56,736	$ 52,015	$ 38,600
Accrued compensation and benefits	62,271	47,622
Trade payables	19,169	19,938
Accrued rent	19,547	15,222
Deferred revenue	13,836	12,533
Deferred compensation	3,918	4,552
Accrued restructuring	2,224	3,768
Accrued transaction processing	2,981	2,972
Other	18,529	17,309
Total	$ 199,211	$ 175,931