Quarterly report pursuant to Section 13 or 15(d)

Organization and Basis of Presentation - Additional Information (Detail)

v3.19.1
Organization and Basis of Presentation - Additional Information (Detail) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2019
Dec. 31, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]    
Date of incorporation Jul. 13, 2005  
Accumulated deficit $ 191,376 $ 186,629