Reconciliation of Net Income (Loss) Amounts and Weighted Average Number of Common and Common Equivalent Shares Used to Determine Basic and Diluted Earnings (Loss) per Common Share (Parenthetical) (Detail) (Convertible Debt Securities, USD $)	12 Months Ended
	Apr. 30, 2013
Convertible Debt Securities
Diluted earnings related to the effect of conversion of convertible debt	$ 499,000