Income Taxes - Income (Loss) Before Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Taxes [Line Items]
Total income before income taxes	$ (6,824)	$ (3,780)	$ (20,216)	$ (18,343)
Ireland
Income Taxes [Line Items]
Total income before income taxes	(12,089)	(10,962)	(22,323)	(15,889)
United States
Income Taxes [Line Items]
Total income before income taxes	9,800	7,019	6,357	(2,816)
France
Income Taxes [Line Items]
Total income before income taxes	$ (4,535)	$ 163	$ (4,250)	$ 362