Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
	Apr. 30, 2024	Apr. 30, 2025	Apr. 30, 2023
Tax Credit Carryforward [Line Items]
Deferred tax assets, valuation allowance	$ 252,682,000		$ 180,571,000
Deferred tax assets, increase in valuation allowance	72,100,000
Unrecognized tax benefits, if recognized, would impact effective income tax rate	100,000
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	599,300,000		487,600,000
Tax credit carryforwards, subject to expiration	1,000,000.0
Federal | Research Tax Credit Carryforward
Tax Credit Carryforward [Line Items]
Tax credit carryforwards	18,800,000
Federal | Charitable Contribution Carryforward
Tax Credit Carryforward [Line Items]
Tax credit carryforwards	25,600,000
State
Tax Credit Carryforward [Line Items]
Net operating loss carryforwards	249,300,000		$ 187,800,000
Tax credit carryforwards, subject to expiration	400,000
State | Research Tax Credit Carryforward
Tax Credit Carryforward [Line Items]
Tax credit carryforwards	$ 14,200,000