401(k) Plan - Additional Information (Details)	12 Months Ended
Jan. 31, 2018
Compensation Related Costs [Abstract]
Maximum annual contributions per employee	100.00%

Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan.

No definition available.

Name:	us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration