License, collaboration and commercial agreements - CSPC (Details) - License and Collaboration Agreement - CSPC - USD ($) $ in Millions		9 Months Ended
Sep. 25, 2018	Sep. 30, 2021
License and collaboration agreements
Upfront, non-refundable payment obligation to be received prior to initial Exclusivity Fee	$ 15.0
Maximum aggregate payments entitled to receive if all milestones successfully achieved	$ 160.0
Percentage of future milestone payments and royalties entitled		50.00%

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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