Stockholders' Equity And Stock-Based Compensation (Summary Of Stock Option Activity) (Details) - Employee Stock Option [Member]	6 Months Ended
Jun. 30, 2020 $ / shares shares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Beginning Balance, Number of shares \| shares	3,749,186
Options granted, Number of shares \| shares	1,823,810
Options exercised, Number of shares \| shares	(750)
Options canceled, Number of shares \| shares	(309,190)
Options expired, Number of shares \| shares	(46,556)
Ending Balance, Number of shares \| shares	5,216,500
Exercisable, Number of shares \| shares	2,468,093
Beginning Balance, Weighted average exercise price per share \| $ / shares	$ 16.18
Options granted, Weighted average exercise price per share \| $ / shares
Options exercised, Weighted average exercise price per share \| $ / shares
Options canceled, Weighted average exercise price per share \| $ / shares
Options expired, Weighted average exercise price per share \| $ / shares
Ending Balance, Weighted average exercise price per share \| $ / shares	14.20
Exercisable, Weighted average exercise price per share \| $ / shares	$ 16.58

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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

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No definition available.

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

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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No definition available.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options of the plan that expired.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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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

Weighted average exercise price as of the balance sheet date for those equity-based payment arrangements exercisable and outstanding.

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Number of share options (or share units) exercised during the current period.

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