Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
Apr. 30, 2022	Apr. 30, 2021
Income Tax Contingency [Line Items]
Increase in valuation allowance	$ 1,500,000
Research and development credits	5,299,000	$ 4,011,000
Valuation allowance	5,170,000	3,706,000
Undistributed foreign earnings	20,600,000
Foreign tax credit	0	0
Potential benefits	1,800,000	$ 1,200,000
Domestic Tax Authority
Income Tax Contingency [Line Items]
Research and development credits	3,800,000
State and Local Jurisdiction
Income Tax Contingency [Line Items]
Research and development credits	$ 4,000,000

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible foreign tax credit carryforwards.

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