Investments and Fair Value Measurements - Securities in Unrealized Loss Position (Details) - USD ($) $ in Thousands	Oct. 31, 2022	Jan. 31, 2022
Fair Value
Less than 12 Months	$ 911,964	$ 283,262
12 Months or Greater	12,332	0
Total	924,296	283,262
Unrealized Losses
Less than 12 Months	(10,454)	(405)
12 Months or Greater	(24)	0
Total	(10,478)	(405)
U.S. Government and Agency Securities
Fair Value
Less than 12 Months	669,567	8,024
12 Months or Greater	0	0
Total	669,567	8,024
Unrealized Losses
Less than 12 Months	(8,000)	(12)
12 Months or Greater	0	0
Total	(8,000)	(12)
Corporate Bonds
Fair Value
Less than 12 Months	73,075	130,007
12 Months or Greater	12,332	0
Total	85,407	130,007
Unrealized Losses
Less than 12 Months	(763)	(240)
12 Months or Greater	(24)	0
Total	(787)	(240)
Commercial Paper
Fair Value
Less than 12 Months	169,322	145,231
12 Months or Greater	0	0
Total	169,322	145,231
Unrealized Losses
Less than 12 Months	(1,691)	(153)
12 Months or Greater	0	0
Total	$ (1,691)	$ (153)