Debt - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	1 Months Ended				1 Months Ended
	Nov. 30, 2008	Nov. 30, 2008 Standby Letters of Credit	Jan. 31, 2013 Revolving Credit Facility Amendment Five	Jan. 31, 2013 Combined Letter Of Credit And Credit Card Services Subfacility	Jul. 31, 2007 Revolving Line of Credit
Debt Instrument [Line Items]
Revolving line of credit with a borrowing capacity			$ 30.00	$ 2.65
Line of credit facility current borrowing capacity percentage			100.00%
Loan and security agreement, issue date					Jul. 18, 2007
Loan and security agreement, expiration date					Jan. 31, 2015
Standby letter of credit in favor of its landlord	$ 0.5	$ 0.1