Income Taxes - Schedule of Income Tax Reconciliation (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Apr. 30, 2014	Apr. 30, 2013	Apr. 30, 2012
Income Tax Disclosure [Abstract]
Income tax expense at statutory rate	$ 2,035	$ 1,775	$ 863
State and local taxes, net of federal income tax benefit (expense)	165	128	3
Tax credits (state, net of federal benefit)	(134)	(118)	(76)
Effects of differing US and foreign tax rates	(30)	(106)	(61)
(Decrease) increase in valuation allowance	(9)	(14)	73
Other items, net	(44)	(125)	(63)
Net income tax expense	$ 1,983	$ 1,540	$ 739