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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)

v3.8.0.1
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, 2017
Oct. 31, 2016
Oct. 31, 2017
Oct. 31, 2016
Segment Reporting Information [Line Items]        
Total revenues $ 23,430 $ 19,961 $ 57,322 $ 59,983
United States Revenue [Member]        
Segment Reporting Information [Line Items]        
Total revenues $ 6,105 $ 6,905 $ 20,180 $ 22,040
Total Revenues [Member] | Customer Concentration Risk [Member]        
Segment Reporting Information [Line Items]        
% of total revenues 10.00% 10.00% 10.00% 10.00%
Total Revenues [Member] | Customer Concentration Risk [Member] | United States Revenue [Member]        
Segment Reporting Information [Line Items]        
% of total revenues 26.10% 34.60% 35.20% 36.70%