Warrants - Summary of Warrants Outstanding (Detail) - $ / shares |
6 Months Ended | |||
|---|---|---|---|---|
Jun. 30, 2018 |
Apr. 06, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Class of Warrant or Right [Line Items] | ||||
| Exercise Price | $ 2.00 | |||
| Warrants Outstanding | 3,077,425 | 2,177,425 | 17,559 | |
| Class One [Member] | ||||
| Class of Warrant or Right [Line Items] | ||||
| Exercise Price | $ 3.10 | |||
| Warrants Outstanding | 48,387 | |||
| Expiration Date | Sep. 19, 2022 | |||
| Class Two [Member] | ||||
| Class of Warrant or Right [Line Items] | ||||
| Exercise Price | $ 3.10 | |||
| Warrants Outstanding | 462,106 | |||
| Expiration Date | May 10, 2024 | |||
| Class Three [Member] | ||||
| Class of Warrant or Right [Line Items] | ||||
| Exercise Price | $ 3.10 | |||
| Warrants Outstanding | 602,414 | |||
| Expiration Date | Jul. 25, 2024 | |||
| Class Four [Member] | ||||
| Class of Warrant or Right [Line Items] | ||||
| Exercise Price | $ 3.10 | |||
| Warrants Outstanding | 1,064,518 | |||
| Expiration Date | Nov. 08, 2024 | |||
| Class Five [Member] | ||||
| Class of Warrant or Right [Line Items] | ||||
| Exercise Price | $ 2.00 | |||
| Warrants Outstanding | 900,000 | |||
| Expiration Date | Apr. 10, 2023 |