Income Taxes - Reconciliation (Details) - USD ($)	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of the U.S. statutory income tax rate to the Company's effective tax rate
Federal income tax (benefit) at statutory rate (as a percent)	(21.00%)	(34.00%)	(34.00%)
Change in tax rate (as a percent)	(0.00%)	29.60%	0.10%
Permanent items (as a percent)	(0.50%)	0.10%	0.90%
Other (as a percent)	0.50%	(0.90%)	0.20%
Amended Tax Returns (as a percent)	(0.00%)	(4.50%)	(0.00%)
Change in valuation allowance (as a percent)	21.00%	9.70%	32.80%
Effective income tax rate (as a percent)	0.00%	0.00%	0.00%
Unrecognized tax benefits related to interest and penalties accrued	$ 0

Percentage of difference between reported income tax and expected income tax due to amended tax returns.

No definition available.

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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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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to changes in the valuation allowance for deferred tax assets.

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Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

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