Fair Value Measurements (Details) - USD ($) $ in Thousands	Jul. 31, 2025	Jan. 31, 2025
Financial Assets:
Marketable securities	$ 6,580,073	$ 6,442,329
Privately held debt securities included in strategic investments	3,946	4,450
U.S. government agency securities
Financial Assets:
Marketable securities	4,789,387	4,415,930
Agency bonds
Financial Assets:
Marketable securities	991,578	1,174,484
Corporate and other debt securities
Financial Assets:
Marketable securities	730,731	720,795
Treasury bills
Financial Assets:
Marketable securities	65,414	110,279
Commercial paper
Financial Assets:
Marketable securities	2,963	20,841
Fair Value, Recurring Basis
Financial Assets:
Cash equivalents	752,345	867,001
Marketable securities	6,580,073	6,442,329
Publicly held equity securities included in strategic investments	82,755	35,280
Privately held debt securities included in strategic investments	3,946	4,450
Total financial assets	7,419,119	7,349,060
Fair Value, Recurring Basis | U.S. government agency securities
Financial Assets:
Marketable securities	4,789,387	4,415,930
Fair Value, Recurring Basis | Agency bonds
Financial Assets:
Marketable securities	991,578	1,174,484
Fair Value, Recurring Basis | Corporate and other debt securities
Financial Assets:
Marketable securities	730,731	720,795
Fair Value, Recurring Basis | Treasury bills
Financial Assets:
Marketable securities	65,414	110,279
Fair Value, Recurring Basis | Commercial paper
Financial Assets:
Marketable securities	2,963	20,841
Fair Value, Recurring Basis | Money market funds
Financial Assets:
Cash equivalents	693,125	825,044
Fair Value, Recurring Basis | Treasury bills
Financial Assets:
Cash equivalents	59,220	17,965
Fair Value, Recurring Basis | Agency bonds
Financial Assets:
Cash equivalents		23,992
Fair Value, Recurring Basis | Level 1
Financial Assets:
Cash equivalents	693,125	825,044
Marketable securities	0	0
Publicly held equity securities included in strategic investments	82,755	35,280
Privately held debt securities included in strategic investments	0	0
Total financial assets	775,880	860,324
Fair Value, Recurring Basis | Level 1 | U.S. government agency securities
Financial Assets:
Marketable securities	0	0
Fair Value, Recurring Basis | Level 1 | Agency bonds
Financial Assets:
Marketable securities	0	0
Fair Value, Recurring Basis | Level 1 | Corporate and other debt securities
Financial Assets:
Marketable securities	0	0
Fair Value, Recurring Basis | Level 1 | Treasury bills
Financial Assets:
Marketable securities	0	0
Fair Value, Recurring Basis | Level 1 | Commercial paper
Financial Assets:
Marketable securities	0	0
Fair Value, Recurring Basis | Level 1 | Money market funds
Financial Assets:
Cash equivalents	693,125	825,044
Fair Value, Recurring Basis | Level 1 | Treasury bills
Financial Assets:
Cash equivalents	0	0
Fair Value, Recurring Basis | Level 1 | Agency bonds
Financial Assets:
Cash equivalents		0
Fair Value, Recurring Basis | Level 2
Financial Assets:
Cash equivalents	59,220	41,957
Marketable securities	6,580,073	6,442,329
Publicly held equity securities included in strategic investments	0	0
Privately held debt securities included in strategic investments	0	0
Total financial assets	6,639,293	6,484,286
Fair Value, Recurring Basis | Level 2 | U.S. government agency securities
Financial Assets:
Marketable securities	4,789,387	4,415,930
Fair Value, Recurring Basis | Level 2 | Agency bonds
Financial Assets:
Marketable securities	991,578	1,174,484
Fair Value, Recurring Basis | Level 2 | Corporate and other debt securities
Financial Assets:
Marketable securities	730,731	720,795
Fair Value, Recurring Basis | Level 2 | Treasury bills
Financial Assets:
Marketable securities	65,414	110,279
Fair Value, Recurring Basis | Level 2 | Commercial paper
Financial Assets:
Marketable securities	2,963	20,841
Fair Value, Recurring Basis | Level 2 | Money market funds
Financial Assets:
Cash equivalents	0	0
Fair Value, Recurring Basis | Level 2 | Treasury bills
Financial Assets:
Cash equivalents	59,220	17,965
Fair Value, Recurring Basis | Level 2 | Agency bonds
Financial Assets:
Cash equivalents		23,992
Fair Value, Recurring Basis | Level 3
Financial Assets:
Cash equivalents	0	0
Marketable securities	0	0
Publicly held equity securities included in strategic investments	0	0
Privately held debt securities included in strategic investments	3,946	4,450
Total financial assets	3,946	4,450
Fair Value, Recurring Basis | Level 3 | U.S. government agency securities
Financial Assets:
Marketable securities	0	0
Fair Value, Recurring Basis | Level 3 | Agency bonds
Financial Assets:
Marketable securities	0	0
Fair Value, Recurring Basis | Level 3 | Corporate and other debt securities
Financial Assets:
Marketable securities	0	0
Fair Value, Recurring Basis | Level 3 | Treasury bills
Financial Assets:
Marketable securities	0	0
Fair Value, Recurring Basis | Level 3 | Commercial paper
Financial Assets:
Marketable securities	0	0
Fair Value, Recurring Basis | Level 3 | Money market funds
Financial Assets:
Cash equivalents	0	0
Fair Value, Recurring Basis | Level 3 | Treasury bills
Financial Assets:
Cash equivalents	$ 0	0
Fair Value, Recurring Basis | Level 3 | Agency bonds
Financial Assets:
Cash equivalents		$ 0