Build-to-Suit Lease Obligation - Additional Information (Detail) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2015 USD ($) ft²	Jun. 30, 2015 USD ($) ft²	Jun. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 ft²
Build To Suit Lease Obligation [Line Items]
Build to suit lease | ft²	143,000	143,000
Amounts capitalized under build-to-suit transactions		$ 283	$ 16,800
Area of surrender property | ft²	8,007	8,007
Derecognized portion of build-to-suit asset	$ 3,200
Derecognized portion of build-to-suit lease obligation	3,100
Build-to-suit lease obligation current liability	196	$ 196		$ 698
Build-to-suit lease obligation non-current liability	$ 16,920	16,920		$ 18,711
Build-to-suit Lease 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		3,900
Capitalized Interest Cost [Member]
Build To Suit Lease Obligation [Line Items]
Amounts capitalized under build-to-suit transactions		$ 2,500
Laboratory Space [Member]
Build To Suit Lease Obligation [Line Items]
Build to suit lease | ft²	43,625	43,625			51,632
Lease expiry period		August 2024
Build to suit lease extension term	5 years