Build-to-Suit Lease Obligation - Additional Information (Detail) $ in Thousands	3 Months Ended	9 Months Ended
	Jun. 30, 2015 USD ($) ft²	Sep. 30, 2015 USD ($) ft²	Sep. 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
Amounts capitalized under build-to-suit lease transactions		$ 283	$ 18,085
Area of property surrendered | ft²		8,007
Derecognized portion of build-to-suit asset	$ 3,241	$ 3,241
Derecognized portion of build-to-suit lease obligation	$ 3,176	3,176
Current portion of build-to-suit lease obligation		235		$ 698
Build-to-suit lease obligation non-current liability		16,905		$ 18,711
Build-to-suit Lease Property and Equipment [Member]
Build To Suit Lease Obligation [Line Items]
Amounts capitalized under build-to-suit lease transactions		14,500
Tenant Improvements [Member]
Build To Suit Lease Obligation [Line Items]
Amounts capitalized under build-to-suit lease transactions		3,900
Capitalized Interest Cost [Member]
Build To Suit Lease Obligation [Line Items]
Amounts capitalized under build-to-suit lease transactions		$ 3,000
Laboratory Space [Member]
Build To Suit Lease Obligation [Line Items]
Build to suit lease | ft²	43,625				51,632
Lease expiry period		August 2024
Build to suit lease extension term	5 years