Build-to-Suit Lease Obligation - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended	3 Months Ended	6 Months Ended
	Jun. 30, 2014 sqft	Dec. 31, 2013 Laboratory space [Member] Y sqft	Jun. 30, 2014 Property and equipment [Member]	Jun. 30, 2014 Tenant improvements [Member]
Build To Suit Lease Obligation [Line Items]
Operating lease space, in square feet	127,000	52,000
Lease expiry period	June 2019	July 2024
Optional lease extension term, in years		5
Amounts capitalized under build-to-suit transactions	$ 16,800		$ 14,500	$ 2,300
Interest capitalized during construction period for build-to-suit transactions	450
Build-to-suit lease obligation current liability	645
Build-to-suit lease obligation non-current liability	$ 16,605