Subsequent Event - Additional Information (Detail) - shares |
1 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
Jan. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Subsequent Event [Line Items] | ||||
| Number of Shares, Options granted | 1,399,522 | 664,100 | 1,471,142 | |
| Subsequent event [Member] | ||||
| Subsequent Event [Line Items] | ||||
| Number of Shares, Options granted | 1,207,240 | |||