Property and Equipment (Details) - USD ($) $ in Thousands	Apr. 30, 2022	Apr. 30, 2021
Property, Plant and Equipment [Line Items]
Gross property plant and equipment	$ 34,894	$ 34,009
Accumulated depreciation and amortization	(31,240)	(30,581)
Net property plant and equipment	3,654	3,428
Buildings and leasehold improvements
Property, Plant and Equipment [Line Items]
Gross property plant and equipment	17,448	16,944
Computer equipment and purchased software
Property, Plant and Equipment [Line Items]
Gross property plant and equipment	12,443	12,089
Office furniture and equipment
Property, Plant and Equipment [Line Items]
Gross property plant and equipment	$ 5,003	$ 4,976