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Concentration of Credit Risk - Additional Information (Detail) - Customer
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Concentration Risk [Line Items]    
Number of major customers 3 3
Net Accounts Receivable | Three Largest Customers | Customer Concentration Risk    
Concentration Risk [Line Items]    
Percentage of net accounts receivable accounted for by three largest customers 56.20% 29.80%