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Collaboration Agreements and Revenues - Summary of Revenue Recognized Under the Collaboration Agreements - Additional Information 4 (Detail) $ in Millions | 3 Months Ended
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Jun. 30, 2021 USD ($)
Europe [Member] |
Revenue Recognition, Multiple-deliverable Arrangements [Line Items] |
Remainder of transaction price, variable consideration from estimated future co-development billing | $ 10.7
Europe [Member] | Astellas Agreement [Member] |
Revenue Recognition, Multiple-deliverable Arrangements [Line Items] |
Changes in revenue from changes to estimated variable consideration | 0.4
U.S./RoW and China [Member] |
Revenue Recognition, Multiple-deliverable Arrangements [Line Items] |
Remainder of transaction price, variable consideration from estimated future co-development billing | 34.1
U.S./RoW and China [Member] | AstraZeneca Agreements [Member] |
Revenue Recognition, Multiple-deliverable Arrangements [Line Items] |
Changes in revenue from changes to estimated variable consideration | $ 0.2

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