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SHORT-TERM INVESTMENTS (Tables) | 12 Months Ended
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Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract] |
Debt Securities, Available-for-sale [Table Text Block] | The following table summarizes the available-for-sale investments held as of December 31, 2018. There were no available-for-sale investments in prior periods.
Description |  | Fair value |
U.S. government and agency securities and treasuries |  | $ | 66,218,000 |

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- Definition Tabular disclosure of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -URI http://asc.fasb.org/topic&trid=2196928 + Details
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