Furniture, Equipment and Purchased Software (Detail) - USD ($) $ in Thousands	Apr. 30, 2017	Apr. 30, 2016
Property, Plant and Equipment [Line Items]
Gross property plant and equipment	$ 30,208	$ 35,833
Accumulated depreciation and amortization	(28,153)	(32,437)
Net property plant and equipment	2,055	3,396
Buildings and leasehold improvements
Property, Plant and Equipment [Line Items]
Gross property plant and equipment	14,704	20,975
Computer equipment and purchased software
Property, Plant and Equipment [Line Items]
Gross property plant and equipment	10,886	10,303
Office furniture and equipment
Property, Plant and Equipment [Line Items]
Gross property plant and equipment	$ 4,618	$ 4,555