Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Apr. 30, 2023	Apr. 30, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 81,352	$ 98,459
U.S. Treasury securities	7,305	0
Marketable securities	16,632	16,826
Total	105,289	115,285
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	81,352	98,459
U.S. Treasury securities		0
Marketable securities		16,826
Total	105,289	115,285
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
U.S. Treasury securities	0	0
Marketable securities	0	0
Total	0	0
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
U.S. Treasury securities	0	0
Marketable securities	0	0
Total	$ 0	$ 0