Quarterly report pursuant to Section 13 or 15(d)

Net Income (Loss) Per Share of Common Stock - Schedule of Antidilutive Securities Excluded from Computation of Diluted Weighted Average Shares Outstanding (Detail)

v3.19.1
Net Income (Loss) Per Share of Common Stock - Schedule of Antidilutive Securities Excluded from Computation of Diluted Weighted Average Shares Outstanding (Detail) - shares
3 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Potentially antidilutive securities outstanding excluded from the computation of diluted weighted average shares 40,071,858 43,742,709
Employee Stock Options [Member]    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Potentially antidilutive securities outstanding excluded from the computation of diluted weighted average shares 9,084,744 7,475,106
Warrants [Member]    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Potentially antidilutive securities outstanding excluded from the computation of diluted weighted average shares 30,987,114 36,267,603