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FAIR VALUE MEASUREMENTS - EQUITY INVESTMENT (Details) - Equity Investment - USD ($) | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2019 | Sep. 30, 2018 | Sep. 30, 2019 | Sep. 30, 2018 | Dec. 31, 2007
Equity Investments [Line Item] |  |  |  |  |
Number of shares owned |  |  |  |  | 13,842,625
Cost method investments cost basis |  |  |  |  | $ 0
Fair value of equity investment | $ 373,000 |  | $ 373,000 |  |
Increase (decrease) in fair value of equity investment | (195,000) | $ 205,000 | (195,000) | $ (270,000) |
Gain (loss) related to foreign currency translation | $ (14,000) | $ (30,000) | $ (17,000) | $ (68,000) |
Maximum |  |  |  |  |
Equity Investments [Line Item] |  |  |  |  |
Cost method investments Ownership |  |  |  |  | 20.00%

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