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Balance Sheet Components - Additional Information (Details) - USD ($)
 1 Months Ended 3 Months Ended
Dec. 31, 2018
Apr. 30, 2019
Apr. 30, 2018
Jan. 31, 2019
Balance Sheet Components [Line Items]        
Amortization expense for deferred sales commissions   $ 400,000    
Impairment loss in relation to deferred commission costs capitalized   0    
Global Telecomm Corporation        
Balance Sheet Components [Line Items]        
Procured raw material from related party   200,000    
Prepaid inventory deposits   $ 300,000   $ 0
Global Telecomm Corporation | Convertible Promissory Note        
Balance Sheet Components [Line Items]        
Investment in privately-held company $ 1,300,000      
Convertible promissory note, maturity period 18 months      
Convertible promissory note, interest rate 10.00%      
Maximum        
Balance Sheet Components [Line Items]        
Amortization expense for deferred sales commissions     $ 100,000  
Customer relationships        
Balance Sheet Components [Line Items]        
Estimated life (in years)   5 years