Annual report pursuant to Section 13 and 15(d)

Net Income (Loss) Per Share - Effect of Anti-dilutive Securities (Detail)

v3.19.1
Net Income (Loss) Per Share - Effect of Anti-dilutive Securities (Detail) - shares
12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Effect of Anti-dilutive Securities 9,857,822 4,268,984
Employee Stock Option and Restricted Stock Units [Member]    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Effect of Anti-dilutive Securities 8,625,088 3,148,931
Warrant [Member]    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Effect of Anti-dilutive Securities 1,232,734 1,120,053