Concentrations of Risk - Additional Information (Detail) - USD ($)	May. 31, 2015	Feb. 28, 2015	May. 31, 2014	Feb. 28, 2014
Concentration Risk [Line Items]
Minimum Insurance available to depositors under the FDIC's general deposit insurance rules	$ 250,000
Cash balances not federally insured	15,000,000
Cash in bank accounts	19,047,000	$ 15,346,000	$ 13,266,000	$ 5,316,000
Canada [Member]
Concentration Risk [Line Items]
Cash in bank accounts	1,000,000
Mexico [Member]
Concentration Risk [Line Items]
Cash in bank accounts	$ 1,500,000