Collaboration Revenue - Summary of Deferred Revenue (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Deferred Revenue Arrangement [Line Items]
Current portion of deferred revenue	$ 16,522	$ 7,793
Long-term portion of deferred revenue	96,687	65,778
Deferred revenue	113,209	73,571
Upfront and milestone payments
Deferred Revenue Arrangement [Line Items]
Deferred revenue	107,228	72,207
Prepaid research and development services
Deferred Revenue Arrangement [Line Items]
Deferred revenue	1,045	1,319
Prepaid product and service revenues
Deferred Revenue Arrangement [Line Items]
Deferred revenue	4,365	0
Other
Deferred Revenue Arrangement [Line Items]
Deferred revenue	$ 571	$ 45