Quarterly report pursuant to Section 13 or 15(d)

Concentrations - Additional Information (Detail)

v3.19.3
Concentrations - Additional Information (Detail) - Product Concentration Risk - Customer
3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Sep. 30, 2019
Sep. 30, 2018
Dec. 31, 2018
Concentration Risk [Line Items]          
Number of customers which represented more than 10% of the Company's accounts receivable     0   1
Sales Revenue, Net          
Concentration Risk [Line Items]          
Number of customers which represented more than 10% of the Company's revenue 0 0 0 0  
Concentration Risk Percentage 100.00% 100.00% 100.00% 100.00%  
Account Receivable          
Concentration Risk [Line Items]          
Concentration Risk Percentage     10.00%   10.00%
Minimum | Sales Revenue, Net          
Concentration Risk [Line Items]          
Concentration Risk Percentage 10.00% 10.00% 10.00% 10.00%