Income Taxes - Summary of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Apr. 30, 2015	Apr. 30, 2014
Deferred tax assets:
Accrued employee benefit expenses	$ 535	$ 462
Allowance for doubtful accounts	53	68
Deferred compensation	1,573	1,432
Tax credits	237	304
Unrecognized actuarial loss, defined benefit plans	4,206	3,486
Other	354	98
Total deferred tax assets	6,958	5,850
Deferred tax liabilities:
Book basis in excess of tax basis of property, plant and equipment	(1,594)	(1,826)
Prepaid pension	(2,164)	(2,098)
Other	134	155
Total deferred tax liabilities	(3,624)	(3,769)
Less: valuation allowance	(10)	(50)
Net deferred tax assets (liabilities)	3,324	2,031
Deferred tax assets classified in the balance sheet:
Current	856	646
Non-current	2,468	1,385
Net deferred tax assets (liabilities)	$ 3,324	$ 2,031

The cumulative amount of future tax effects arising from the unused tax credit carryforward attributable to some other tax carryforward (not otherwise stated) that cannot be utilized on the tax return during the period and that may be carried forward and are expected to more likely than not be used to reduce taxable income or taxes payable in future periods.

No definition available.