Commitments and Contingencies - Operating Leases - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2015 USD ($) Option	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Operating Leased Assets [Line Items]
Rent expenses, net of sublease income	$ 1,828,000	$ 1,953,000	$ 2,286,000
Rental income from the sublease agreement	$ 0	$ 0	$ 0
2091 Building [Member]
Operating Leased Assets [Line Items]
Expiry of lease of 2091 Building	Mar. 31, 2018
Operating leases renewal term, duration	5 years
Operating leases options | Option	2