Income Taxes - Irish statutory rate reconciliation (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
The differences between the U.S. federal statutory income tax rate to the Company's effective tax rate
Provision at statutory income tax rate (as a percent)	21.00%		35.00%
Effective tax rate (as a percent)	2.16%	4.67%	(5.04%)
Ireland
The differences between the U.S. federal statutory income tax rate to the Company's effective tax rate
Provision at statutory income tax rate (as a percent)	25.00%	25.00%	25.00%
Foreign rate differential (as a percent)	(6.96%)	(7.51%)	(18.17%)
Share-based compensation (as a percent)	(1.17%)	0.28%	1.52%
Non-deductible executive compensation (as a percent)	(0.51%)	(0.72%)	(1.03%)
Uncertain tax positions (as a percent)	(0.63%)	(4.00%)	(6.55%)
Research and development tax credit carryforwards (as a percent)	2.50%	1.79%	1.21%
Federal tax reforms - Tax rate change (as a percent)			(4.66%)
Foreign exchange loss (as a percent)		8.52%
Change in valuation allowance (as a percent)	(14.90%)	(18.82%)	(5.15%)
Other (as a percent)	(1.17%)	0.13%	2.79%
Effective tax rate (as a percent)	2.16%	4.67%	(5.04%)