Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Schedule of Potentially Dilutive Securities Excluded from Computation of Diluted Weighted-Average Shares Outstanding (Details)

v3.19.1
Summary of Significant Accounting Policies - Schedule of Potentially Dilutive Securities Excluded from Computation of Diluted Weighted-Average Shares Outstanding (Details) - shares
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]      
Potentially dilutive securities excluded from computation of diluted weighted-average shares outstanding 808,101 6,124,133 3,374,407
Options to Purchase Ordinary Shares      
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]      
Potentially dilutive securities excluded from computation of diluted weighted-average shares outstanding 665,219 248,128 49,330
Preferred Shares Convertible into Ordinary Shares      
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]      
Potentially dilutive securities excluded from computation of diluted weighted-average shares outstanding   5,686,663 3,032,457
Unvested Restricted Stock Units      
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]      
Potentially dilutive securities excluded from computation of diluted weighted-average shares outstanding 36,924    
Unvested Restricted Ordinary Shares      
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]      
Potentially dilutive securities excluded from computation of diluted weighted-average shares outstanding 86,068 189,342 292,620
Warrants      
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]      
Potentially dilutive securities excluded from computation of diluted weighted-average shares outstanding 19,890