401(k) Plan (Details) - USD ($)	12 Months Ended
	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2019
Defined Contribution Plan Disclosure [Line Items]
Total expense related defined benefit plan	$ 6,000,000	$ 4,000,000	$ 3,000,000
401(k) plan
Defined Contribution Plan Disclosure [Line Items]
Employer maximum matching contribution amount per employee per year	2,000
RRSP | CANADA
Defined Contribution Plan Disclosure [Line Items]
Employer maximum matching contribution amount per employee per year	$ 2,000