Leases - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2009 sqft
Leases [Line Items]
Percentage ceiling on rent increases, annually, capital lease	3.00%
San Carlos facility capital leases, termination date	Oct. 05, 2016
Future minimum rental receipts under the San Carlos facility subleases	$ 4.8
Book value of assets, gross	2.7	2.3
Net book value of assets	1.2	1.0
Operating Sublease term commenced start date	August 2010
Operating Sublease term commenced period	114 months
Operating Sublease term commenced end date	January 31, 2020
Rent expense for operating leases	$ 3.2	$ 2.9	$ 2.8
Pfizer, Inc. [Member]
Leases [Line Items]
Operating sublease				126,285