Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2022	Apr. 30, 2021	Apr. 30, 2020
Income Tax Disclosure [Line Items]
Effective income tax rate	7.60%	8.60%	1.00%
Tax benefits realized from the recognition of stock option deductions	$ 2,067	$ 763	$ 878
Foreign net operating loss carryforwards	3,873	3,141
Unrecognized tax benefits that, if recognized, would impact effective tax rate	18	25	34
Liability for potential penalties and interest	11	15
Research and development state tax credits	522	640	703
United Kingdom and New Zealand
Income Tax Disclosure [Line Items]
Foreign net operating loss carryforwards	3,700
State and Local Jurisdiction
Income Tax Disclosure [Line Items]
Operating loss carryforwards	$ 1,200
Operating loss carryforwards expiration year	2037
Research and development state tax credits	$ 561	$ 555	$ 427
Foreign Tax Authority
Income Tax Disclosure [Line Items]
Operating loss carryforwards	$ 19,000