Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating Loss Carryforwards [Line Items]
Valuation allowance	$ 110,518	$ 92,789
Decrease in valuation allowance	(17,700)
Unrecognized tax benefits	3,730	2,466	$ 1,109	$ 0
Unrecognized tax benefits, amount netted against deferred tax assets	3,600	2,400
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	278,000
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards		$ 138,000
Germany | Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	21,000
United Kingdom | Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	$ 2,100