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Fair Value Measurements - Contingent Consideration (Details) - USD ($) $ in Thousands | 9 Months Ended |  |
--- | --- | --- | ---
Sep. 30, 2021 | Dec. 31, 2020 | Feb. 25, 2019
Fair Value Measurements |  |  |
Contingent consideration under royalty purchase agreements | $ 75 | $ 75 |
Bioasis Technologies Inc [Member] | Royalty Purchase Agreement [Member] |  |  |
Fair Value Measurements |  |  |
Changes in estimated fair value of contingent consideration | $ 0 |  |
Contingent consideration under royalty purchase agreements |  |  | $ 100

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