Fair Value Measurements - Marketable Securities (Details) - U.S. government treasury securities - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2024	Jan. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Amortized cost, due withen one year	$ 520,006	$ 1,383,226
Amortized cost, due after one year and withen three years	690,211	0
Amortized cost, total	1,210,217	1,383,226
Unrealized loss, due withen one year	543	(2,422)
Unrealized loss, due after one year and withen three years	(2,774)	0
Unrealized loss, total	2,231	2,422
Due within one year	519,463	1,380,804
Due after one year and within three years	692,985	0
Total short-term investments	$ 1,212,448	$ 1,380,804