Shareholders' Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		3 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Class Of Stock [Line Items]
Ordinary shares, shares authorized			100,000,000		100,000,000
Ordinary shares, issued			20,758,348		16,214,883
Ordinary shares, outstanding			20,758,348		16,214,883
Issuance of ordinary shares, consideration received net of underwriting discounts and commissions and issuance costs			$ 161,447	$ 64,193
Underwritten Public Offering
Class Of Stock [Line Items]
Issuance of ordinary shares, shares	4,207,317	1,682,926
Additional ordinary shares exercised under underwriters option to purchase at the public offering price	548,780	219,512
Issuance of ordinary shares, price per share	$ 41.00	$ 41.00
Issuance of ordinary shares, consideration received net of underwriting discounts and commissions and issuance costs	$ 161,400	$ 64,200