Stock-Based Compensation - Summary of Activity Relating to Restricted Stock (Detail) - Restricted Stock Units [Member] - shares |
3 Months Ended | 6 Months Ended | |
---|---|---|---|
Jun. 30, 2018 |
Jun. 30, 2018 |
Jun. 30, 2017 |
|
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
Outstanding, Shares at beginning balance-Restricted stock | 29,100 | ||
Granted, Shares- Restricted stock | 71,400 | 32,500 | |
Vested, Shares-Restricted stock | 0 | (14,550) | 0 |
Forfeited, Shares-Restricted stock | (900) | ||
Outstanding, Shares at ending balance-Restricted stock | 85,050 | 85,050 |