Geographic Information Narrative (Details) - customer	3 Months Ended		9 Months Ended		12 Months Ended
	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2017	Oct. 31, 2016	Jan. 31, 2017
Customer concentration risk | Accounts receivable
Concentration Risk [Line Items]
Number of customers accounting for 10 percent or more of the AR concentration risk	2		2		1
Customer concentration risk | Revenues
Concentration Risk [Line Items]
Number of customers accounting for 10 percent or more of the revenue concentration risk	2	2	2	2
Geographic concentration | Property and equipment | United States
Concentration Risk [Line Items]
Concentration risk, percentage			10.00%		10.00%
Customer One | Customer concentration risk | Accounts receivable
Concentration Risk [Line Items]
Concentration risk, percentage			30.00%		30.00%
Customer One | Customer concentration risk | Revenues
Concentration Risk [Line Items]
Concentration risk, percentage	29.00%	27.00%	28.00%	25.00%
Customer Two | Customer concentration risk | Accounts receivable
Concentration Risk [Line Items]
Concentration risk, percentage			27.00%
Customer Two | Customer concentration risk | Revenues
Concentration Risk [Line Items]
Concentration risk, percentage	24.00%	21.00%	20.00%	18.00%