Investments and Fair Value Measurements - Securities in Unrealized Loss Position (Details) - USD ($) $ in Thousands	Jul. 31, 2023	Jan. 31, 2023
Fair Value
Less than 12 Months	$ 1,019,490	$ 1,353,843
12 Months or Greater	7,407	9,846
Total	1,026,897	1,363,689
Unrealized Losses
Less than 12 Months	(948)	(5,560)
12 Months or Greater	(12)	(56)
Total	(960)	(5,616)
U.S. Government and Agency Securities
Fair Value
Less than 12 Months	355,851	1,162,226
12 Months or Greater	0	7,959
Total	355,851	1,170,185
Unrealized Losses
Less than 12 Months	(282)	(4,530)
12 Months or Greater	0	(42)
Total	(282)	(4,572)
Corporate Bonds
Fair Value
Less than 12 Months	26,906	50,258
12 Months or Greater	7,407	1,887
Total	34,313	52,145
Unrealized Losses
Less than 12 Months	(50)	(328)
12 Months or Greater	(12)	(14)
Total	(62)	(342)
Commercial Paper
Fair Value
Less than 12 Months	636,733	141,359
12 Months or Greater	0	0
Total	636,733	141,359
Unrealized Losses
Less than 12 Months	(616)	(702)
12 Months or Greater	0	0
Total	$ (616)	$ (702)