Restructuring (Details) $ in Thousands			3 Months Ended	12 Months Ended
	Jun. 19, 2017 USD ($) position	Jun. 21, 2016 USD ($) Employee	Jun. 30, 2017 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Restructuring Cost and Reserve [Line Items]
Asset impairment charges				$ 392,097	$ 0	$ 0
Severance costs	$ 5,800
Other restructuring costs	$ 3,000
Employee serverance and other personnel benefits:
Balance				1,854	0
Expenses, Net				5,897	17,162
Cash				(6,806)	(14,697)
Noncash				(945)	(611)
Balance				0	1,854	0
Reorganization Plan 2017 [Member] | Workforce reduction [Member]
Employee serverance and other personnel benefits:
Balance				0
Expenses, Net				5,897
Cash				(5,768)
Noncash				(129)
Balance				0	0
2016 Reorganization Plan [Member]
Restructuring Cost and Reserve [Line Items]
Number of positions eliminated due to restructuring | Employee		162
Stock option term		1 year
Expected restructuring costs		$ 17,200
2016 Reorganization Plan [Member] | Workforce reduction [Member]
Employee serverance and other personnel benefits:
Balance				1,854	0
Expenses, Net				0	17,162
Cash				(1,038)	(14,697)
Noncash				(816)	(611)
Balance				$ 0	$ 1,854	$ 0
Ionsys [Member] | Disposal Group, Disposed of by Means Other than Sale, Not Discontinued Operations, Abandonment [Member]
Restructuring Cost and Reserve [Line Items]
Number of positions eliminated due to restructuring | position	57
Pre-tax restructuring charge			$ 276,900
Percentage of positions eliminated	15.00%
Asset impairment charges			268,100
Severance costs			$ 8,800