Income Tax Expense (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Nov. 02, 2015
Operating Loss Carryforwards [Line Items]
U.S. Federal statutory rate to net income (loss) before taxes	34.00%
Deferred tax assets, valuation allowance	$ 67,172	$ 57,883
Change in valuation allowance	9,300
Net change in valuation allowance, recorded as tax expense	10,052	8,930	$ 2,417
Deferred tax asset related to compensation benefits as well as Federal and State net operating loss carryforwards	9,800
Undistributed earnings of foreign subsidiaries	108
Provision for income taxes	$ (9,337)	$ (62)	$ (10)
Effective tax rate	15.60%
Internal Revenue Service (IRS)
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards, domestic	$ 166,700
Internal Revenue Service (IRS) | Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Tax credit carryforward amount	8,000
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards, state and local	97,600
State and Local Jurisdiction | Research Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Tax credit carryforward amount	8,600
Income Tax Expense (Benefit)
Operating Loss Carryforwards [Line Items]
Net change in valuation allowance, recorded as tax expense	10,100
3.25% Convertible Senior Notes | Convertible Senior Notes
Operating Loss Carryforwards [Line Items]
Convertible notes, stated percentage				3.25%
Adjustments to Additional Paid in Capital, convertible debt	$ 9,600