Bank Borrowings - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Line of Credit Facility [Line Items]
Line of credit amendment date	Mar. 05, 2012
Frequency of payments for commitment fees	Quarterly
Commitment fees	$ 154	$ 107	$ 51
Minimum
Line of Credit Facility [Line Items]
Commitment fees on unused line of credit, percentage	0.375%
Maximum
Line of Credit Facility [Line Items]
Commitment fees on unused line of credit, percentage	0.50%
Before Amendment
Line of Credit Facility [Line Items]
Line of credit maturity date	Jan. 29, 2013
Line of credit, maximum borrowing capacity	10,000
After Amendment
Line of Credit Facility [Line Items]
Line of credit maturity date	Jul. 29, 2013
Line of credit, maximum borrowing capacity	25,000
Second Amendment
Line of Credit Facility [Line Items]
Line of credit amendment date	Jul. 25, 2013
Line of credit maturity date	Jul. 25, 2018
Line of credit, maximum borrowing capacity	$ 50,000