Effective Income Tax Rate Reconciliation, Tax Cuts And Jobs Act Of 2017, Impact, Percent

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards that are subject to expiration dates.

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Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying domestic federal statutory income tax rate to pretax income (loss) from continuing operation, attributable to excess tax benefit for share-based compensation cost.

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Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The amount of the tax credit carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

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Amount of unrecognized tax benefits.

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The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate.

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Amount of increase (decrease) in the valuation allowance for a specified deferred tax asset.

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Income Taxes - Narrative (Details) $ in Thousands		12 Months Ended
Income Taxes - Narrative (Details) $ in Thousands	Jan. 01, 2018 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Income Tax Disclosure [Abstract]
Effective tax rate		(0.07%)	0.53%	0.01%
Deferred tax assets, valuation allowance		$ 49,439	$ 45,364	$ 64,300
Decrease in deferred tax asset, valuation allowance			22,600
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards expiration		900
Unrecognized excess tax benefit	$ 1,600
Unrecognized tax benefits		10,973	10,200	$ 17,370	$ 14,130
Unrecognized tax benefits that impact effective tax rate		0
Federal
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards		172,300	172,900
Tax credit carryforwards		$ 8,800	7,100
State
Operating Loss Carryforwards [Line Items]
Impact of Tax Act in income tax rate (less than)		0.01
Operating loss carryforwards		$ 38,500	38,500
Tax credit carryforwards		$ 9,700	$ 8,300