Equity Incentive Plans and Employee Stock Purchase Plan - Stock Options (Details) - Employee Stock Option	6 Months Ended
Jul. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	4 years
One Year Anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting rights percentage	25.00%
13 to 36 Months
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting rights percentage	75.00%

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration