Build-to-Suit Lease Obligation - Additional Information (Detail) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2016 USD ($) ft²	Jun. 30, 2015 ft²	Dec. 31, 2015 USD ($) ft²	Dec. 31, 2013 ft²
Build To Suit Lease Obligation [Line Items]
Build to suit lease | ft²	158,000
Area of property surrendered | ft²			8,000
Derecognized portion of build-to-suit asset			$ 3,200
Derecognized portion of build-to-suit lease obligation			3,200
Build-to-suit building, historical cost	$ 18,400
Total build-to-suit lease obligation, including current and non-current portions	17,400
Build-to-suit lease obligation, excluding current portion	$ 17,278		17,406
Laboratory Space [Member]
Build To Suit Lease Obligation [Line Items]
Build to suit lease | ft²		44,000		52,000
Lease expiry period	August 2024
Build to suit lease extension term		5 years
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			3,600
Capitalized Interest Cost [Member]
Build To Suit Lease Obligation [Line Items]
Amounts capitalized under build-to-suit lease transactions			$ 3,500