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Summary of Significant Accounting Policies - Long Term Investments (Details) - USD ($) $ in Millions | Sep. 30, 2018 | Jan. 01, 2018 | Dec. 31, 2017
--- | --- | --- | ---
Dealflo Limited |  |  |
Long Term Investments |  |  |
Equity investment |  | $ 0.5 | $ 0.3
Other Assets |  |  |
Long Term Investments |  |  |
Long Term Investments | $ 4.1 |  | $ 4.4

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