Shareholders' Equity (Summary Of Stock Option Activity) (Details) - Stock Options [Member]	3 Months Ended
Mar. 31, 2020 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding
Outstanding Options, Number of Shares, Balance at beginning \| shares	3,495,601
Options granted, Number of Shares \| shares	492,580
Options cancelled/expired, Number of Shares \| shares	(18,229)
Outstanding Options, Number of Shares, Balance at ending \| shares	3,969,952
Exercisable, Number of Shares \| shares	3,063,812
Vested and expected to vest, Number of Shares \| shares	3,756,712
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price
Options, Outstanding, Weighted Average Exercise Price, Balance at beginning \| $ / shares	$ 0.46
Options granted, Weighted Average Exercise Price \| $ / shares	0.28
Options cancelled/expired, Weighted Average Exercise Price \| $ / shares	0.28
Options, Outstanding, Weighted Average Exercise Price, Balance at ending \| $ / shares	0.44
Exercisable, Weighted Average Exercise Price \| $ / shares	0.47
Vested and expected to vest, Outstanding, Weighted Average Exercise Price \| $ / shares	$ 0.44

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.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iii)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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Weighted average price of options that were either forfeited or expired.

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-Name Accounting Standards Codification
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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.

+ References

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

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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
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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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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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-Publisher FASB
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Number of fully vested and expected to vest options outstanding that can be converted into shares under option plan. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Weighted-average exercise price, at which grantee can acquire shares reserved for issuance, for fully vested and expected to vest options outstanding. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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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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