Income Taxes - Effective Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2025	Apr. 30, 2024	Apr. 30, 2023
Income Tax Disclosure [Abstract]
Expected benefit at federal statutory rate	$ (60,422)	$ (58,570)	$ (56,314)
State tax expense—net of federal benefit	272	292	306
Impact of foreign operations	(156)	(158)	(75)
Federal research and development credit	(3,562)	(3,087)	(2,489)
Change in valuation allowance	64,770	66,556	32,481
Stock-based compensation	(1,072)	(5,001)	25,806
Meals and entertainment	228	207	95
Other permanent items	918	553	865
Provision for income taxes	$ 976	$ 792	$ 675