Income Taxes - Summary of reconciliation of U.K. statutory income tax rate and effective income tax rates (Details 2)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Effects of:
State income taxes, net of federal benefit	(5.30%)	11.00%	(16.60%)
U.S. domestic manufacturing deduction	0.00%	(0.90%)	(12.00%)
Facilitative transaction costs	0.00%	54.20%	22.00%
Research and development tax credits	(35.20%)	(119.70%)	(90.60%)
Withholding taxes (U.K. entities)	4.20%	12.40%	245.50%
U.K. stamp duty	0.50%	0.00%	9.40%
Subpart F income	3.20%	0.00%	4.00%
Changes in valuation allowance	0.00%	35.10%	6.00%
Foreign tax credits	9.80%	29.50%	(14.00%)
Non-deductible officer compensation	5.50%	4.90%	0.00%
Benefit of other foreign tax regimes	(42.80%)	(170.60%)	(135.40%)
Accrual of outside basis differences	7.90%	(0.30%)	0.90%
Impacts of internal restructuring	(4.60%)	0.00%	0.00%
Gain on sale of Taiwan factory	(5.20%)	(0.00%)	(0.00%)
Change in tax rate	1.80%	(105.00%)	0.00%
Uncertain tax positions	5.30%	(13.10%)	88.90%
Other, net	2.20%	5.30%	(14.40%)
Effective income tax rate	(29.40%)	(211.85%)	62.80%
Other Foreign
Effects of:
Non-U.K. tax rate differential	4.40%	26.10%	(50.90%)
U.K.
Reconciliation Of Statutory Federal Tax Rate [Line Items]
Statutory income tax rate	19.00%	19.25%	20.00%