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Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) | 1 Months Ended | 12 Months Ended
--- | --- | ---
Jan. 31, 2018 | Oct. 31, 2017 | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |
Credit losses on marketable securities |  |  | $ 0 | $ 0 |
Impairment loss on right-of-use assets |  |  | 238,000 | 1,158,000 |
Deferred revenue |  |  | $ 132,300,000 |  |
Increase in the forecast of total expected costs |  |  | 7.00% |  |
Reduction in revenue due to increase in budget during the year |  |  | $ 6,700,000 |  |
Defined contribution plan, maximum annual contributions per employee, percent |  |  | 100.00% |  |
Defined matching contribution plan |  |  | $ 700,000 | 0 | $ 0
AbbVie Biotechnology Limited |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |
Upfront payments |  | $ 205,000,000 |  |  |
Upfront payment received | $ 200,000,000 | 5,000,000 |  |  |
Exclusive option rights exercised for each program |  | 250,000,000 |  |  |
Cash payment received, non-refundable | $ 200,000,000 | 5,000,000 |  |  |
AbbVie Biotechnology Limited | Collaborative Arrangement, Transaction with Party to Collaborative Arrangement |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |
Collaboration revenue |  |  | 21,100,000 | $ 21,200,000 | $ 27,500,000
Innovent |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |
Collaboration revenue |  |  | 0 |  |
Development milestone |  |  | 11,500,000 |  |
Sales milestone |  |  | $ 112,500,000 |  |
Minimum |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |
Property, plant, and equipment useful life |  |  | 3 years |  |
Maximum |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |
Property, plant, and equipment useful life |  |  | 5 years |  |
Maximum | AbbVie Biotechnology Limited |  |  |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |  |  |
Additional milestone payments per program related to initiation of certain clinical studies and regulatory approval |  | $ 242,800,000 |  |  |

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