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FAIR VALUE MEASUREMENTS - Narrative (Detail) - USD ($) shares in Thousands, $ in Thousands | 3 Months Ended | 32 Months Ended |
--- | --- | --- | ---
Mar. 31, 2021 | Mar. 31, 2020 | Mar. 31, 2021 | Jul. 20, 2018
Debt Securities, Available-for-sale [Line Items] |  |  |  |
Purchase of additional Sangamo France shares | $ 65 | $ 0 |  |
Sangamo France | Share purchase agreement and tender offer agreement |  |  |  |
Debt Securities, Available-for-sale [Line Items] |  |  |  |
Number of free shares held by the holders (in shares) |  |  |  | 477
Number of shares acquired (in shares) |  |  | 453 |
Purchase of additional Sangamo France shares | $ 1,100 |  |  |
Number of free shares outstanding subject to purchase (in shares) | 24 |  |  |

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