Tax Effects of Temporary Differences That Give Rise to Significant Portions of Deferred Tax Assets and Deferred Tax Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Apr. 30, 2014	Apr. 30, 2013
Deferred tax assets:
Accruals and expenses not deducted for tax purposes	$ 1,024	$ 1,018
State net operating loss carryforwards	389	358
Intangible assets and fixed asset basis differences	1,347	1,191
Nonqualified stock options	1,154	1,287
Total gross deferred tax assets	3,914	3,854
Less valuation allowance	466	421
Net deferred tax assets	3,448	3,433
Deferred tax liabilities:
Capitalized computer software development costs	(4,109)	(3,334)
Net gains/losses on trading securities	(566)	(458)
Goodwill	(598)	(511)
Other	(529)	(528)
Total gross deferred tax liabilities	(5,802)	(4,831)
Net deferred tax liabilities	$ (2,354)	$ (1,398)