Build-to-Suit Lease Obligation - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
	Dec. 31, 2013 sqft	Sep. 30, 2014
Build To Suit Lease Obligation [Line Items]
Operating lease space, in square feet		127,000
Lease expiry period		June 2019
Amounts capitalized under build-to-suit transactions		$ 18,085
Interest capitalized during construction period for build-to-suit transactions		945
Build-to-suit lease obligation current liability		781
Build-to-suit lease obligation non-current liability		18,249
Laboratory Space [Member]
Build To Suit Lease Obligation [Line Items]
Operating lease space, in square feet	52,000
Lease expiry period		July 2024
Optional lease extension term, in years	5 years
Property and equipment [Member]
Build To Suit Lease Obligation [Line Items]
Amounts capitalized under build-to-suit transactions		14,500
Tenant Improvements [Member]
Build To Suit Lease Obligation [Line Items]
Amounts capitalized under build-to-suit transactions		$ 3,600