Fair Value Measurement (Details) - USD ($) $ in Thousands	Jan. 31, 2024	Jan. 31, 2023
Financial Assets:
Total marketable securities	$ 818,145	$ 357,716
Treasury bills
Financial Assets:
Total cash equivalents		10,000
Commercial paper
Financial Assets:
Total marketable securities		62,470
Treasury bills & U.S. government securities
Financial Assets:
Total marketable securities	641,192	234,540
Corporate bonds
Financial Assets:
Total marketable securities	1,991	46,486
Municipal bonds
Financial Assets:
Total marketable securities		6,308
Agency bonds
Financial Assets:
Total marketable securities	174,962	7,912
Recurring
Financial Assets:
Total cash equivalents	509,053	329,769
Total marketable securities	818,145	357,716
Total	1,327,198	687,485
Recurring | Money market funds
Financial Assets:
Total cash equivalents	509,053	319,801
Recurring | Treasury bills
Financial Assets:
Total cash equivalents		9,968
Recurring | Commercial paper
Financial Assets:
Total marketable securities		62,470
Recurring | Treasury bills & U.S. government securities
Financial Assets:
Total marketable securities	641,192	234,540
Recurring | Corporate bonds
Financial Assets:
Total marketable securities	1,991	46,486
Recurring | Municipal bonds
Financial Assets:
Total marketable securities		6,308
Recurring | Agency bonds
Financial Assets:
Total marketable securities	174,962	7,912
Recurring | Level 1
Financial Assets:
Total cash equivalents	509,053	329,769
Total marketable securities	816,154	242,452
Total	1,325,207	572,221
Recurring | Level 1 | Money market funds
Financial Assets:
Total cash equivalents	509,053	319,801
Recurring | Level 1 | Treasury bills
Financial Assets:
Total cash equivalents		9,968
Recurring | Level 1 | Commercial paper
Financial Assets:
Total marketable securities		0
Recurring | Level 1 | Treasury bills & U.S. government securities
Financial Assets:
Total marketable securities	641,192	234,540
Recurring | Level 1 | Corporate bonds
Financial Assets:
Total marketable securities	0	0
Recurring | Level 1 | Municipal bonds
Financial Assets:
Total marketable securities		0
Recurring | Level 1 | Agency bonds
Financial Assets:
Total marketable securities	174,962	7,912
Recurring | Level 2
Financial Assets:
Total cash equivalents	0	0
Total marketable securities	1,991	115,264
Total	1,991	115,264
Recurring | Level 2 | Money market funds
Financial Assets:
Total cash equivalents	0	0
Recurring | Level 2 | Treasury bills
Financial Assets:
Total cash equivalents		0
Recurring | Level 2 | Commercial paper
Financial Assets:
Total marketable securities		62,470
Recurring | Level 2 | Treasury bills & U.S. government securities
Financial Assets:
Total marketable securities	0	0
Recurring | Level 2 | Corporate bonds
Financial Assets:
Total marketable securities	1,991	46,486
Recurring | Level 2 | Municipal bonds
Financial Assets:
Total marketable securities		6,308
Recurring | Level 2 | Agency bonds
Financial Assets:
Total marketable securities	0	0
Recurring | Level 3
Financial Assets:
Total	$ 0	$ 0