Marketable Securities - Schedule of Marketable Securities (Details) - USD ($) $ in Thousands	Jan. 31, 2025	Jan. 31, 2024
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 844,807	$ 818,246
Gross Unrealized Gains	56	29
Gross Unrealized Losses	(428)	(130)
Estimated Fair Value	844,435	818,145
Treasury bills & U.S. government securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	703,740	641,263
Gross Unrealized Gains	0	29
Gross Unrealized Losses	(421)	(100)
Estimated Fair Value	703,319	641,192
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	93,989	1,993
Gross Unrealized Gains	36	0
Gross Unrealized Losses	0	(2)
Estimated Fair Value	94,025	1,991
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	42,371
Gross Unrealized Gains	20
Gross Unrealized Losses	0
Estimated Fair Value	42,391
Yankee bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	4,707
Gross Unrealized Gains	0
Gross Unrealized Losses	(7)
Estimated Fair Value	$ 4,700
Agency bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		174,990
Gross Unrealized Gains		0
Gross Unrealized Losses		(28)
Estimated Fair Value		$ 174,962