Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Additional Information (Details)

v3.10.0.1
Summary of Significant Accounting Policies - Additional Information (Details)
3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2018
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Customer
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Sep. 30, 2017
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Customer
Sep. 30, 2018
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Customer
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Sep. 30, 2017
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Customer
Dec. 31, 2017
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Customer
Jun. 30, 2018
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Jan. 01, 2018
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Jun. 12, 2017
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Mar. 27, 2017
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Accounting Policies [Line Items]                  
Number of authorized shares of common stock | shares 500,000,000   500,000,000            
Percentage of contract value invoiced to customer on contract fully executed     50.00%            
Percentage of contract value invoiced to customer on subscription service operational and ready to go live     50.00%            
Percentage of contract value invoiced subscription service renewals on renewal contract executed     100.00%            
Deferred revenue         $ 18,500,000 $ 17,400,000      
Deferred revenue added from new billings $ 12,100,000   $ 27,900,000            
Revenues 9,211,000 $ 6,846,000 25,045,000 $ 17,244,000          
Allowance for potential credit losses 0   0   0        
Accumulated deficit $ (97,598,000)   $ (97,598,000)   $ (97,595,000)        
Customer Concentration Risk | Accounts Receivable                  
Accounting Policies [Line Items]                  
Number of customers | Customer     1   3        
Customer Concentration Risk | Revenues                  
Accounting Policies [Line Items]                  
Number of customers | Customer 2 2 2 2          
Customer One | Customer Concentration Risk | Accounts Receivable                  
Accounting Policies [Line Items]                  
Concentration risk percentage     58.00%   18.00%        
Customer One | Customer Concentration Risk | Revenues                  
Accounting Policies [Line Items]                  
Concentration risk percentage 23.00% 17.00% 22.00% 18.00%          
Customer Two | Customer Concentration Risk | Accounts Receivable                  
Accounting Policies [Line Items]                  
Concentration risk percentage         18.00%        
Customer Two | Customer Concentration Risk | Revenues                  
Accounting Policies [Line Items]                  
Concentration risk percentage 15.00% 14.00% 15.00% 10.00%          
Customer Three | Customer Concentration Risk | Accounts Receivable                  
Accounting Policies [Line Items]                  
Concentration risk percentage         14.00%        
United States                  
Accounting Policies [Line Items]                  
Revenues $ 9,000,000   $ 24,300,000            
South Africa                  
Accounting Policies [Line Items]                  
Revenues 200,000   700,000            
Recognition from Beginning Deferred Revenue                  
Accounting Policies [Line Items]                  
Deferred revenue recognized 5,900,000   13,900,000            
Recognition from New Billings of Deferred Revenue                  
Accounting Policies [Line Items]                  
Deferred revenue recognized 3,100,000   $ 10,800,000            
Adoption of Topic 606                  
Accounting Policies [Line Items]                  
Revenues material right recognition period     3 years            
Subscription renewal fees recognition period     1 year            
Deferred revenue             $ 17,300,000    
Capitalized commissions, amortization period     5 years            
Adoption of Topic 606 | Effect of Change Increase/(Decrease)                  
Accounting Policies [Line Items]                  
Deferred revenue             (1,200,000)    
Revenues $ 174,000   $ 296,000            
Accumulated deficit             3,000,000    
Capitalization of commissions             $ 1,800,000    
Minimum                  
Accounting Policies [Line Items]                  
Subscription services initial contract period     1 year            
Maximum                  
Accounting Policies [Line Items]                  
Subscription services initial contract period     5 years            
Expected customer relationship period     5 years            
Amended and Restated Certificate of Incorporation                  
Accounting Policies [Line Items]                  
Number of authorized shares of common stock | shares               500,000,000 8,600,000
Total number of authorized shares | shares                 14,550,000
Amended and Restated Certificate of Incorporation | Series A-2 Convertible Preferred Stock                  
Accounting Policies [Line Items]                  
Convertible preferred stock, terms of conversion     to provide, among other changes, that each share of Series A-2 convertible preferred stock would automatically convert into 0.715548 shares of common stock upon the consummation of an initial public offering of the Company’s capital stock.            
Conversion of preferred stock into common stock | shares                 0.715548