Summary of Significant Accounting Policies (Narrative) (Details)	12 Months Ended
Dec. 31, 2020 USD ($) Segment	Dec. 31, 2019 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Allowance for credit losses related to notes receivable outstanding	$ 0
Intangible assets impairment charges	0
Goodwill impairment charges	0	$ 573,000
Deferred tax assets	$ 4,402,000	$ 372,000
Percentage of revenue specific to customer from net revenue	10.00%	14.00%
Selling, General and Administrative Expenses [Member]
Summary Of Significant Accounting Policies [Line Items]
Advertising and promotion expense	$ 400,000	$ 600,000
ASC 606 [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of reporting segment \| Segment	2
Deferred revenue	$ 17,000
ASC 606 [Member] \| Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Percentage of service revenue that is recognized over a period of time against total revenue	1.00%

Percentage of revenue specific to customer from net revenues.

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Percentage of service revenue that is recognized over a period of time against gross revenue.

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Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable.

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Amount, after allocation of valuation allowances and deferred tax liability, of deferred tax asset attributable to deductible differences and carryforwards, with jurisdictional netting.

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Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of investment in impaired financing receivables for which there is a related allowance for credit losses.

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The amount of impairment loss recognized in the period resulting from the write-down of the carrying amount of an intangible asset (excluding goodwill) to fair value.

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The total expense recognized in the period for promotion, public relations, and brand or product advertising.

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Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

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