Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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Unrecognized cost of unvested share-based compensation awards.

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- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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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No definition available.

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- Definition

The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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-Publisher FASB
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Gross number of share options (or share units) granted during the period.

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No definition available.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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- Definition

Number of options outstanding, including both vested and non-vested options.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average grant-date fair value of non-vested options forfeited.

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No definition available.

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Weighted average grant-date fair value of non-vested options outstanding.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Stock Compensation Plans and Share-Based Compensation Awards - Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Stock Compensation Plans and Share-Based Compensation Awards
Share-based compensation expense	$ 1,758	$ 0	$ 53,893	$ 0
Stock options
Stock Compensation Plans and Share-Based Compensation Awards
Share-based compensation expense	$ 900		$ 1,300
Number outstanding
Granted (in shares)			2,140
Forfeited (in shares)			(19)
Balance at end of period (in shares)	2,121		2,121
Weighted average fair value
Granted (in dollars per share)			$ 6.84
Forfeited (in dollars per share)			6.68
Balance at end of period (in dollars per share)	$ 6.84		$ 6.84
Unrecognized compensation expense	$ 13,100		$ 13,100
Weighted average period outstanding for unvested stock options			3 years 7 months 6 days
Vesting period	4 years
Expiration period	10 years