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MARKETABLE SECURITIES (Tables) | 3 Months Ended
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Mar. 31, 2020
MARKETABLE SECURITIES |
Schedule of net realized (losses) gains and reclassification of net realized (losses) gains from other comprehensive income | ​
​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Three months ended
​ | ​ | March 31,
(in thousands) |  | 2020 |  | 2019
Net realized gain | ​ | $ | — | ​ | $ | 4
Reclassification of net realized gains from other comprehensive income | ​ | $ | — | ​ | $ | 4

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