Concentrations of Risk - Additional Information (Detail) (USD $)	Aug. 31, 2013	Feb. 28, 2013	Aug. 31, 2012	Feb. 29, 2012
Concentration Risk [Line Items]
Minimum Insurance available to depositors under the FDIC's general deposit insurance rules	$ 250,000
Cash balances not federally insured	14,200,000
Cash in bank accounts	17,681,000	6,232,000	13,205,000	10,410,000
Canada [Member]
Concentration Risk [Line Items]
Cash in bank accounts	1,000,000
Mexico [Member]
Concentration Risk [Line Items]
Cash in bank accounts	$ 900,000