Significant Customers and Geographic Information - Additional Information (Details) - Customer	Jul. 31, 2017	Jan. 31, 2017	Jul. 31, 2016
Accounts Receivable | Customer
Concentration Risk [Line Items]
Number of customers comprising 10% or more of total accounts receivable	0	0
Revenue | Customer
Concentration Risk [Line Items]
Number of customers comprising more than 10% of revenues	0		0
Revenue | Geographic Concentration Risk | Foreign Countries
Concentration Risk [Line Items]
Number of customers comprising more than 10% of revenues	0		0