Warrants - Outstanding Warrants To Purchase Common Stock Warrants (Parenthetical) (Detail) - $ / shares |
12 Months Ended | |||
|---|---|---|---|---|
Dec. 31, 2016 |
Sep. 26, 2016 |
Sep. 25, 2016 |
Jan. 30, 2015 |
|
| Private Placement [Member] | ||||
| Class Of Warrant Or Right [Line Items] | ||||
| Exercise Price | $ 4.00 | $ 4.98 | ||
| Subsequent Financing [Member] | ||||
| Class Of Warrant Or Right [Line Items] | ||||
| Exercise Price | 4.00 | 4.98 | ||
| Common Stock [Member] | ||||
| Class Of Warrant Or Right [Line Items] | ||||
| Exercise Price | $ 6.96 | |||
| Common Stock [Member] | Private Placement [Member] | Accredited Investors [Member] | ||||
| Class Of Warrant Or Right [Line Items] | ||||
| Warrants, issued date | Apr. 14, 2016 | |||
| Exercise Price | 4.00 | 4.98 | ||
| Common Stock [Member] | Private Placement [Member] | Placement Agents [Member] | ||||
| Class Of Warrant Or Right [Line Items] | ||||
| Warrants, issued date | Apr. 14, 2016 | |||
| Common Stock [Member] | Subsequent Financing [Member] | ||||
| Class Of Warrant Or Right [Line Items] | ||||
| Warrants, issued date | Jun. 15, 2016 | |||
| Exercise Price | $ 4.00 | $ 4.98 |