Quarterly report pursuant to Section 13 or 15(d)

Condensed Financial Statements - Summary of Certain Statements of Operations Amounts (Detail)

v3.19.1
Condensed Financial Statements - Summary of Certain Statements of Operations Amounts (Detail) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]    
Stock compensation expense $ 1,556 $ (68)
Research and Development [Member]    
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]    
Stock compensation expense 240 (437)
General and Administrative Expense [Member]    
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]    
Stock compensation expense $ 1,316 $ 369