Bank Borrowings - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended			1 Months Ended
	Jun. 30, 2013	Jun. 30, 2013 Before Amendment	Jun. 30, 2013 After Amendment	Jul. 25, 2013 Second Amendment Subsequent Event
Line of Credit Facility [Line Items]
Line of credit amendment date	Mar. 05, 2012			Jul. 25, 2013
Line of credit maturity date		Jan. 29, 2013	Jul. 29, 2013	Jul. 25, 2018
Line of credit, maximum borrowing capacity		$ 10,000	$ 25,000	$ 50,000
Commitment fees on unused line of credit, percentage	0.50%
Frequency of payments for commitment fees	Quarterly