Fair Value Measurements - Marketable Securities (Details) - U.S. government treasury securities - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Apr. 30, 2023	Oct. 31, 2023	Jan. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized cost, due withen one year		$ 638,309	$ 1,383,226
Amortized cost, due after one year and withen three years		818,757	0
Amortized cost, total		1,457,066	1,383,226
Unrealized loss, due withen one year	$ (2,422)	(1,553)
Unrealized loss, due after one year and withen three years	0	(8,478)
Unrealized loss, total	$ 2,422	10,031
Short-term investments		636,756	1,380,804
Marketable securities, non-current		810,279	0
Total short-term investments		$ 1,447,035	$ 1,380,804