Stock-Based Compensation - Summary of Stock-Based Compensation for all Options Granted and Restricted Stock Awards (Detail) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | ||
---|---|---|---|---|
Jun. 30, 2018 |
Jun. 30, 2017 |
Jun. 30, 2018 |
Jun. 30, 2017 |
|
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | ||||
Stock-based compensation expense | $ 408 | $ 371 | $ 810 | $ 864 |
Research and Development [Member] | ||||
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | ||||
Stock-based compensation expense | 120 | 129 | 594 | 240 |
General and Administrative [Member] | ||||
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] | ||||
Stock-based compensation expense | $ 288 | $ 242 | $ 216 | $ 624 |