Furniture, Equipment and Purchased Software (Detail) - USD ($) $ in Thousands	Apr. 30, 2015	Apr. 30, 2014
Property, Plant and Equipment [Line Items]
Gross property plant and equipment	$ 35,180	$ 34,226
Accumulated depreciation and amortization	(31,632)	(30,545)
Net property plant and equipment	3,548	3,681
Buildings and leasehold improvements
Property, Plant and Equipment [Line Items]
Gross property plant and equipment	20,716	20,011
Computer equipment and purchased software
Property, Plant and Equipment [Line Items]
Gross property plant and equipment	10,049	9,842
Office furniture and equipment
Property, Plant and Equipment [Line Items]
Gross property plant and equipment	$ 4,415	$ 4,373