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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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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Number of additional shares authorized for issuance under an established share-based compensation plan.

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No definition available.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Percentage of vesting of share-based compensation awards.

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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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Stock-Based Compensation (Narrative) (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		12 Months Ended	123 Months Ended
	May 31, 2014	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Mar. 31, 2019	Dec. 31, 2008	Dec. 31, 2004
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense		$ 2,688	$ 1,281
Stock-based compensation expense to be recognized through results of operations		$ 8,818			$ 8,818
Employee Stock Award Plan-2008
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for issuance (in shares)		800,169		890,857	800,169	1,900,000
Additional shares authorized (in shares)	1,500,000	0			1,500,000
Employee Stock Award Plan-2008 \| Share-based Compensation Award, Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights		20.00%
Employee Stock Award Plan-2008 \| Share-based Compensation Award, Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights				33.30%
Employee Stock Award Plan-2008 \| Options Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period		10 years
Employee Stock Award Plan-2008 \| Restricted Stock Awards \| Share-based Compensation Award, Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years
Employee Stock Award Plan-2008 \| Restricted Stock Awards \| Share-based Compensation Award, Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		5 years
Director Plan - 2005
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available for issuance (in shares)		49,163		49,163	49,163		300,000