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

Summary of Significant Accounting Policies - Schedule of Potentially Dilutive Securities Excluded from Computation of Diluted Weighted-Average Shares Outstanding (Details) - shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computation of diluted weighted-average shares outstanding	1,258,302	7,807,964
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	1,091,238	248,128
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		7,396,313
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	60,250	163,523
Unvested Restricted Share 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 Performance Restricted Share Units
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from computation of diluted weighted-average shares outstanding	50,000
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

Quarterly report pursuant to Section 13 or 15(d)

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