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v3.20.4

STATEMENTS OF CASH FLOWS DATA (Tables) | 12 Months Ended
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Dec. 31, 2020
Supplemental Cash Flow Elements [Abstract] |
Supplemental schedule of non-cash operating and investing activities |
|  | Year Ended December 31, |
|  | 2020 |  |  | 2019 |  |  | 2018 |
|  | (In thousands) |
Supplemental operating and investing activities: |  |  |  |  |  |  |  |  |  |  |  |
Net unrealized (loss) gain on marketable securities |  | $ | (54 | ) |  | $ | 315 |  |  | $ | 24 |
Operating lease assets obtained in exchange for operating lease liabilities |  |  | 3,575 |  |  |  | 2,473 |  |  |  | — |
Interest paid |  | $ | 388 |  |  | $ | — |  |  | $ | — |

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