Quarterly report pursuant to Section 13 or 15(d)

Common Stock - Summary of Share-Based Compensation Expense for Stock Options and Restricted Stock (Detail)

v3.8.0.1
Common Stock - Summary of Share-Based Compensation Expense for Stock Options and Restricted Stock (Detail)
$ in Thousands
3 Months Ended
Mar. 31, 2018
USD ($)
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]  
Total stock-based compensation $ 181
Research and development [Member]  
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]  
Total stock-based compensation 57
General and administrative [Member]  
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]  
Total stock-based compensation $ 124