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, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Accounts Receivable	94.00%	95.00%
Customer A [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Accounts Receivable	47.00%	47.00%
Customer B [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Accounts Receivable	22.00%	22.00%
Customer C [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Accounts Receivable	25.00%	26.00%