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Segment Information, Significant Customers and Geographic Information - Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area (Parenthetical) (Detail)

v3.10.0.1
Segment Information, Significant Customers and Geographic Information - Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area (Parenthetical) (Detail) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jul. 31, 2018
Jul. 31, 2017
Jul. 31, 2018
Jul. 31, 2017
Segment Reporting Information [Line Items]        
Total revenues $ 11,901 $ 17,225 $ 26,836 $ 33,892
United States Revenue [Member]        
Segment Reporting Information [Line Items]        
Total revenues $ 5,102 $ 7,047 $ 10,889 $ 14,075
Total Revenues [Member] | Customer Concentration Risk [Member] | United States Revenue [Member]        
Segment Reporting Information [Line Items]        
% of total revenues 42.90% 40.90% 40.60% 41.50%