Net Income (Loss) Per Common Share - Schedule of Anti-Dilutive Shares Excluded from Computation of Diluted Net Loss Per Share (Detail) - shares
3 Months Ended 9 Months Ended
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2016
Sep. 30, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Total 4,955,422 8,435,765 6,713,810 7,405,976
Options to Purchase Common Stock        
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Total 4,736,258 6,778,265 6,447,978 5,498,476
Restricted Stock Awards, Including Participating Securities        
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Total 219,164 1,657,500 265,832 1,907,500