Common Stock - Additional Information (Detail) - USD ($) |
9 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2018 |
Dec. 31, 2017 |
Mar. 10, 2017 |
Mar. 03, 2017 |
|
| Equity [Abstract] | ||||
| Common stock, shares authorized | 300,000,000 | 300,000,000 | 300,000,000 | 100,000,000 |
| Common stock, par value | $ 0.0001 | $ 0.0001 | $ 0.0001 | $ 0.0001 |
| Dividends common stock declared or paid | $ 0 | |||
| Warrants outstanding | 317,562 | 317,562 | ||
| Warrants exercise price per share | $ 5.00 | $ 5.00 | ||
| Warrants term | 3 years | 3 years | ||
| Warrants expiration date | Mar. 15, 2020 | Mar. 15, 2020 |