Notes Payable to Related Parties - Schedule of Notes Payable to Related Parties (Parenthetical) (Detail) - Notes Payable to Related Parties [Member] |
12 Months Ended | |
|---|---|---|
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| 0% Promissory Note Due 3/31/19 [Member] | ||
| Notes Payable to Related Parties [Line Items] | ||
| Notes payable, interest rate | 0.00% | 0.00% |
| Notes payable, maturity date | Mar. 31, 2019 | Mar. 31, 2019 |
| 8% Secured Promissory Notes Due 3/31/19 [Member] | ||
| Notes Payable to Related Parties [Line Items] | ||
| Notes payable, interest rate | 8.00% | 8.00% |
| Notes payable, maturity date | Mar. 31, 2019 | Mar. 31, 2019 |
| 8% Promissory Notes Due 3/31/19 [Member] | ||
| Notes Payable to Related Parties [Line Items] | ||
| Notes payable, interest rate | 8.00% | 8.00% |
| Notes payable, maturity date | Mar. 31, 2019 | Mar. 31, 2019 |