Cash Equivalents and Marketable Securities - Available-for Sale Debt Securities by Contractual Maturity (Details) - Debt Securities, Available-For-Sale, Excluding Money Market Accounts - USD ($) $ in Thousands	Oct. 31, 2025	Apr. 30, 2025
Debt Securities, Available-for-sale, Amortized Cost, Fiscal Year Maturity [Abstract]
AFS debt maturities, within one year, amortized cost	$ 435,300	$ 455,613
AFS debt maturities, after one year through five years, amortized cost	135,744	122,194
Amortized Cost	571,044	577,807
Debt Securities, Available-for-sale, Fair Value, Fiscal Year Maturity [Abstract]
AFS debt maturities, within one year, fair value	435,671	455,956
AFS debt maturities, after one year through five years, fair value	136,158	122,374
AFS debt maturities, total fair value	$ 571,829	$ 578,330