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Segment and Geographic Information - Schedule of Customer Concentration by Collaboration Partners and Distribution Entity (Detail) - Customer Concentration Risk [Member] | 12 Months Ended
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Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Percentage of Revenue [Member] | Astellas-Related party [Member] |  |  |
Entity Wide Revenue Major Customer [Line Items] |  |  |
Concentration risk, percentage | 57.00% | 21.00% | 48.00%
Percentage of Revenue [Member] | AstraZeneca [Member] |  |  |
Entity Wide Revenue Major Customer [Line Items] |  |  |
Concentration risk, percentage | 20.00% | 37.00% | 52.00%
Percentage of Revenue [Member] | Falikang—Related party |  |  |
Entity Wide Revenue Major Customer [Line Items] |  |  |
Concentration risk, percentage | 15.00% | 0.00% | 0.00%
Percentage of Accounts Receivable [Member] | Astellas-Related party [Member] |  |  |
Entity Wide Revenue Major Customer [Line Items] |  |  |
Concentration risk, percentage | 63.00% | 10.00% |
Percentage of Accounts Receivable [Member] | AstraZeneca [Member] |  |  |
Entity Wide Revenue Major Customer [Line Items] |  |  |
Concentration risk, percentage | 34.00% | 26.00% |
Percentage of Accounts Receivable [Member] | Falikang—Related party |  |  |
Entity Wide Revenue Major Customer [Line Items] |  |  |
Concentration risk, percentage | 0.00% | 0.00% |

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