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Equity Method Investments (Narrative) (Details) - USD ($) | 9 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2019 | Dec. 31, 2019 | Dec. 31, 2018
Loss from equity method investment in related party |  | $ (66,000) |
StockCross [Member] |  |  |
Percentage of outstanding shares purchased by company |  | 15.00% |
Shares purchased |  | 922,875 |
Per share price |  | $ 3.97 |
Capital distribution | $ 1,600,000 |  |
StockCross [Member] | Siebert [Member] |  |  |
Capital distribution | $ 241,000 |  |

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