Investments - Summary of Marketable Securities (Details) - USD ($) $ in Thousands	Apr. 30, 2026	Jan. 31, 2026
Marketable Securities [Line Items]
Amortized Cost	$ 6,841,552	$ 6,533,457
Gross Unrealized Gains	3,884	12,131
Gross Unrealized Losses	(15,399)	(1,557)
Estimated Fair Value	6,830,037	6,544,031
U.S. government agency securities
Marketable Securities [Line Items]
Amortized Cost	5,598,728	5,373,782
Gross Unrealized Gains	3,650	11,094
Gross Unrealized Losses	(11,962)	(989)
Estimated Fair Value	5,590,416	5,383,887
Agency bonds
Marketable Securities [Line Items]
Amortized Cost	1,198,350	1,095,004
Gross Unrealized Gains	234	1,032
Gross Unrealized Losses	(3,431)	(565)
Estimated Fair Value	1,195,153	1,095,471
Treasury bills
Marketable Securities [Line Items]
Amortized Cost	44,474	64,671
Gross Unrealized Gains	0	5
Gross Unrealized Losses	(6)	(3)
Estimated Fair Value	$ 44,468	$ 64,673

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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+ Details

- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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+ Details