Commitments and Contingencies - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	May 13, 2011	May 12, 2011
Commitments and Contingencies Disclosure [Line Items]
Irrevocable letter of credit delivered as a security for lease obligation				$ 2,400,000.0
Letter of credit amount					2,600,000.0
Irrevocable letter of credit, maturity date					2012-05
Irrevocable letter of credit, additional amount for potential market fluctuation					200,000
Rent expense	2,900,000	2,900,000	2,900,000
Future minimum lease payments under non-cancelable operating leases
2013	3,771,000
2014	3,429,000
2015	2,846,000
2016	2,778,000
2017	2,900,000
Thereafter	9,561,000
Total	25,285,000
On the fifth anniversary of the lease commencement date
Commitments and Contingencies Disclosure [Line Items]
Irrevocable letter of credit delivered as a security for lease obligation				$ 1,200,000.0