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DESCRIPTION OF BUSINESS (Details) $ in Thousands, shares in Millions | 1 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Sep. 30, 2016 USD ($) shares | Dec. 31, 2021 USD ($) | Dec. 31, 2020 USD ($) | Dec. 31, 2019 USD ($) | Apr. 30, 2018 patient
Variable Interest Entity [Line Items] |  |  |  |  |
Number of patients | patient |  |  |  |  | 133
Cash and cash equivalents |  | $ 162,636 | $ 52,389 | $ 48,121 |
Accumulated deficit |  | 316,257 | 315,921 |  |
Negative cash flows from operating activities incurred |  | $ 68,878 | $ 30,837 | $ 37,521 |
Viventia Bio Inc. |  |  |  |  |
Variable Interest Entity [Line Items] |  |  |  |  |
Shares of common stock issued to the selling shareholders (in shares) | shares | 4.0 |  |  |  |
Percentage of voting interests acquired | 19.90% |  |  |  |
Period during which quarterly earn-outs are payable after date of net sales | 15 years |  |  |  |
Period in which acquiree is to use commercially reasonable efforts to achieve marketing authorizations | 7 years |  |  |  |
Viventia Bio Inc. | Vicinium | Collaborative Arrangement, Revenue based on Specified Milestone |  |  |  |  |
Variable Interest Entity [Line Items] |  |  |  |  |
Percentage of net sales of quarterly earn-out payments during earn-out periods | 2.00% |  |  |  |
Viventia Bio Inc. | Vicinium | Collaborative Arrangement, Revenue based on Specified Milestone | United States |  |  |  |  |
Variable Interest Entity [Line Items] |  |  |  |  |
One-time milestone payment upon first sale of product | $ 12,500 |  |  |  |
Viventia Bio Inc. | Vicinium | Collaborative Arrangement, Revenue based on Specified Milestone | Europe |  |  |  |  |
Variable Interest Entity [Line Items] |  |  |  |  |
One-time milestone payment upon first sale of product | 7,000 |  |  |  |
Viventia Bio Inc. | Vicinium | Collaborative Arrangement, Revenue based on Specified Milestone | Japan |  |  |  |  |
Variable Interest Entity [Line Items] |  |  |  |  |
One-time milestone payment upon first sale of product | $ 3,000 |  |  |  |

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