Quarterly report pursuant to Section 13 or 15(d)

Organization and Basis of Presentation - Additional Information (Detail)

v3.10.0.1
Organization and Basis of Presentation - Additional Information (Detail) - USD ($)
$ in Thousands
6 Months Ended
Jun. 30, 2018
Dec. 31, 2017
Organization Consolidation And Presentation Of Financial Statements [Abstract]    
Date of incorporation Jul. 13, 2005  
Accumulated deficit $ 178,133 $ 168,007