Stock-Based Compensation - Total Stockholder Return Restricted Awards (Details) - Total Stockholder Return Restricted Stock Awards $ in Millions	12 Months Ended
Dec. 31, 2018 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance awards, measurement period	3 years
Expected volatility	84.30%
Risk-free interest rate	2.40%
Expected life (in years)	2 years 9 months 18 days
Expected dividend yield	0.00%
Unrecognized compensation expense	$ 3.1
Weighted-average remaining period for recognition of unrecognized compensation costs	2 years 2 months 12 days
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentages attainable during period	0.00%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentages attainable during period	200.00%

Share Based Compensation Arrangement By Share Based Payment Award, Performance Measurement Period

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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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- Definition

Unrecognized cost of unvested share-based awards, other than options, awarded to employees as compensation.

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- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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- Definition

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

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- Definition

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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- Definition

Percentage of vesting of share-based compensation awards.

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- Definition

Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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-Topic 718
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