Fair Value Measurement (Details) - USD ($)	Jan. 31, 2022	Jan. 31, 2021
Financial Assets:
Total marketable securities	$ 115,940,000	$ 102,828,000
Commercial paper
Financial Assets:
Total marketable securities	15,343,000	23,171,000
Corporate bonds
Financial Assets:
Total marketable securities	91,432,000	79,657,000
Municipal bonds
Financial Assets:
Total marketable securities	9,165,000
Recurring
Financial Assets:
Total cash equivalents	1,056,555,000	219,999,000
Total marketable securities	115,940,000	102,828,000
Total	1,172,495,000	322,827,000
Financial Liabilities:
Foreign currency derivative		571,000
Total		571,000
Recurring | Commercial paper
Financial Assets:
Total marketable securities	15,343,000	23,171,000
Recurring | Corporate bonds
Financial Assets:
Total marketable securities	91,432,000	79,657,000
Recurring | Municipal bonds
Financial Assets:
Total marketable securities	9,165,000
Recurring | Corporate bonds
Financial Assets:
Total cash equivalents		1,477,000
Recurring | Money market
Financial Assets:
Total cash equivalents	1,056,555,000	198,523,000
Recurring | Commercial paper
Financial Assets:
Total cash equivalents		19,999,000
Recurring | Level 1
Financial Assets:
Total cash equivalents	1,056,555,000	198,523,000
Total marketable securities	0	0
Total	1,056,555,000	198,523,000
Financial Liabilities:
Foreign currency derivative		0
Total		0
Recurring | Level 1 | Commercial paper
Financial Assets:
Total marketable securities	0	0
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 | Corporate bonds
Financial Assets:
Total cash equivalents		0
Recurring | Level 1 | Money market
Financial Assets:
Total cash equivalents	1,056,555,000	198,523,000
Recurring | Level 1 | Commercial paper
Financial Assets:
Total cash equivalents		0
Recurring | Level 2
Financial Assets:
Total cash equivalents	0	21,476,000
Total marketable securities	115,940,000	102,828,000
Total	115,940,000	124,304,000
Financial Liabilities:
Foreign currency derivative		571,000
Total		571,000
Recurring | Level 2 | Commercial paper
Financial Assets:
Total marketable securities	15,343,000	23,171,000
Recurring | Level 2 | Corporate bonds
Financial Assets:
Total marketable securities	91,432,000	79,657,000
Recurring | Level 2 | Municipal bonds
Financial Assets:
Total marketable securities	9,165,000
Recurring | Level 2 | Corporate bonds
Financial Assets:
Total cash equivalents		1,477,000
Recurring | Level 2 | Money market
Financial Assets:
Total cash equivalents	0	0
Recurring | Level 2 | Commercial paper
Financial Assets:
Total cash equivalents		19,999,000
Recurring | Level 3
Financial Assets:
Total cash equivalents	0	0
Total marketable securities	0	0
Total	0	0
Financial Liabilities:
Foreign currency derivative		0
Total	0	0
Recurring | Level 3 | Commercial paper
Financial Assets:
Total marketable securities	0	0
Recurring | Level 3 | Corporate bonds
Financial Assets:
Total marketable securities	0	0
Recurring | Level 3 | Municipal bonds
Financial Assets:
Total marketable securities	0
Recurring | Level 3 | Corporate bonds
Financial Assets:
Total cash equivalents		0
Recurring | Level 3 | Money market
Financial Assets:
Total cash equivalents	$ 0	0
Recurring | Level 3 | Commercial paper
Financial Assets:
Total cash equivalents		$ 0