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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 9 Months Ended
Oct. 31, 2018
Oct. 31, 2017
Oct. 31, 2018
Oct. 31, 2017
Segment Reporting Information [Line Items]        
Total revenues $ 18,611 $ 23,430 $ 45,447 $ 57,322
United States Revenue [Member]        
Segment Reporting Information [Line Items]        
Total revenues $ 8,124 $ 6,105 $ 19,013 $ 20,180
Total Revenues [Member] | Customer Concentration Risk [Member] | United States Revenue [Member]        
Segment Reporting Information [Line Items]        
% of total revenues 43.70% 26.10% 41.80% 35.20%