Quarterly report pursuant to Section 13 or 15(d)

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

v3.19.3
Net Loss Per Share of Common Stock - Schedule of Antidilutive Securities Excluded from Computation of Diluted Weighted Average Shares Outstanding (Detail) - shares
9 Months Ended
Sep. 30, 2019
Sep. 30, 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 42,804,865 38,513,380
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 12,465,806 7,248,198
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 30,339,059 31,265,182