Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share (Detail)

v3.19.3
Summary of Significant Accounting Policies - Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share (Detail) - shares
 3 Months Ended 9 Months Ended
Sep. 30, 2019
Sep. 30, 2018
Sep. 30, 2019
Sep. 30, 2018
Summary Of Significant Accounting Policies [Line Items]        
Total potentially dilutive securities 6,876,595 6,840,737 6,876,595 6,840,737
Warrant Issued to Private Investors [Member]        
Summary Of Significant Accounting Policies [Line Items]        
Total potentially dilutive securities 4,702,354 3,035,688 4,702,354 3,035,688
Employee Stock Option [Member]        
Summary Of Significant Accounting Policies [Line Items]        
Total potentially dilutive securities 566,753 656,494 566,753 656,494
Restricted Stock Units (RSUs) [Member]        
Summary Of Significant Accounting Policies [Line Items]        
Total potentially dilutive securities 1,607,488 2,276,996 1,607,488 2,276,996
Performance Share Units [Member]        
Summary Of Significant Accounting Policies [Line Items]        
Total potentially dilutive securities   871,559   871,559