Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Taxes
Loss before income taxes	$ (180,559)	$ (181,268)	$ (230,674)
Provision for income taxes
Current	10,110	951	6,364
Deferred	0	0	0
Total	$ 10,110	$ 951	$ 6,364
Effective tax rate (as a percent)	(5.60%)	(0.52%)	(2.76%)
Provision for income taxes on undistributed earnings	$ 0
Undistributed earnings	0
Deferred tax assets:
Net operating loss carryforwards	2,239	$ 4,541
Research and development tax credit carryforwards	3,955	2,405
Fixed assets and acquired intangibles	6,839	7,275
Share-based compensation	13,208	10,895
Accruals	2,109	2,285
Other	476	21
Subtotal	28,826	27,422
Valuation allowance	(28,465)	(26,822)
Total deferred tax assets	361	600
Deferred tax liabilities:
Prepaid assets	(361)	(600)
Total deferred tax liabilities	(361)	(600)
Net deferred tax assets/liabilities	$ 0	$ 0
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%	0.00%
Foreign rate differential (as a percent)	(23.11%)	(14.62%)	(0.99%)
Change in valuation allowance (as a percent)	(0.89%)	(4.42%)	(2.42%)
Share-based compensation (as a percent)	(0.27%)	(4.15%)	0.00%
Non-deductible executive compensation (as a percent)	(1.07%)	(1.09%)	0.00%
Uncertain tax positions (as a percent)	(8.55%)	(3.88%)	(0.25%)
Research and development tax credit carryforwards (as a percent)	1.93%	2.05%	1.00%
Other (as a percent)	1.36%	0.59%	(0.10%)
Effective tax rate (as a percent)	(5.60%)	(0.52%)	(2.76%)
Cayman Islands
Income Taxes
Loss before income taxes	$ (185,099)	$ (107,074)	$ (235,306)
Provision for income taxes
Current	0	0	$ 0
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)			0.00%
United States
Income Taxes
Loss before income taxes	(18,441)	(45,960)	$ 5,189
Provision for income taxes
Current	9,859	883	6,223
Ireland
Income Taxes
Loss before income taxes	23,323	(27,013)	0
Provision for income taxes
Current	$ 219	45	0
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%
Other
Income Taxes
Loss before income taxes	$ (342)	(1,221)	(557)
Provision for income taxes
Current	$ 32	$ 23	$ 141