Nature of Business and Summary of Significant Accounting Policies - Summary of Company's Customers Accounts Receivable (Detail) - Customer Concentration Risk [Member] - Accounts Receivable [Member]	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Accounts Receivable	95.00%	92.00%
Customer A [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Accounts Receivable	47.00%	36.00%
Customer B [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Accounts Receivable	22.00%	28.00%
Customer C [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Accounts Receivable	26.00%	28.00%