Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
	Apr. 30, 2025	Apr. 30, 2026	Apr. 30, 2024
Tax Credit Carryforward [Line Items]
Deferred tax assets, valuation allowance	$ 320,939,000		$ 252,682,000
Deferred tax assets, increase in valuation allowance	68,200,000
Unrecognized tax benefits, if recognized, would impact effective income tax rate	200,000
Unrecognized tax benefits, cumulative interest and penalties	0		0
Unrecognized tax benefits, anticipated significant change over the next 12 months	0
Forecast
Tax Credit Carryforward [Line Items]
Unrecognized tax benefits, if recognized, would impact effective income tax rate		$ 0
Federal
Tax Credit Carryforward [Line Items]
Net operating loss carryforwards	764,700,000		599,300,000
Tax credit carryforwards, subject to expiration	1,000,000.0
Federal | Research Tax Credit Carryforward
Tax Credit Carryforward [Line Items]
Tax credit carryforwards	25,900,000
Federal | Charitable Contribution Carryforward
Tax Credit Carryforward [Line Items]
Tax credit carryforwards	14,200,000
State
Tax Credit Carryforward [Line Items]
Net operating loss carryforwards	310,700,000		$ 249,300,000
Tax credit carryforwards, subject to expiration	400,000
State | Research Tax Credit Carryforward
Tax Credit Carryforward [Line Items]
Tax credit carryforwards	$ 18,900,000