Fair Value Measurements - Marketable Securities (Details) - U.S. government treasury securities - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Apr. 30, 2024	Oct. 31, 2023	Jan. 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized cost, due withen one year	$ 676,643		$ 520,006
Amortized cost, due after one year and withen three years	588,959		690,211
Amortized cost, total	1,265,602		1,210,217
Unrealized loss, due withen one year	1,758	$ (543)
Unrealized loss, due after one year and withen three years	5,552	2,774
Unrealized loss, total	7,310	$ 2,231	2,200
Short-term investments	674,885		519,463
Marketable securities, non-current	583,407		692,985
Total short-term investments	$ 1,258,292		$ 1,212,448