Annual report pursuant to Section 13 and 15(d)

Segment Information, Significant Customers and Geographic Information - Schedule of Revenue by Major Customers by Reporting Segments (Detail)

v3.8.0.1
Segment Information, Significant Customers and Geographic Information - Schedule of Revenue by Major Customers by Reporting Segments (Detail) - Customer Concentration Risk [Member] - Total Revenues [Member]
 12 Months Ended
Jan. 31, 2018
Jan. 31, 2017
Jan. 31, 2016
Revenue, Major Customer [Line Items]      
% of total revenues 10.00% 10.00% 10.00%
Customer A [Member]      
Revenue, Major Customer [Line Items]      
% of total revenues 37.00% 30.00% 28.00%
Customer B [Member]      
Revenue, Major Customer [Line Items]      
% of total revenues     10.00%