Significant Accounting Policies - Additional Information (Detail)
|3 Months Ended|
Apr. 30, 2018
|Accounting Policies [Abstract]|
|Performance obligation, contracts expected duration||1 year|
Period in which remaining performance obligation is expected to be recognized as revenue, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.
Reference 1: http://www.xbrl.org/2003/role/presentationRef