Significant Components of Deferred Income Tax (Benefit) Expense Attributable to Income from Continuing Operations before Income Taxes (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Apr. 30, 2014	Apr. 30, 2013	Apr. 30, 2012
Significant Components Of Deferred Income Tax Expense [Line Items]
Deferred tax expense (benefit)	$ 582	$ 351	$ (126)
(Decrease) increase in the valuation allowance for deferred tax assets	45	(187)	34
Deferred Income Tax Expense (Benefit), Net of Valuation Allowance, Total	$ 627	$ 164	$ (92)