Summary of significant accounting policies - Summary of Assets and liabilities Measured at Fair Value on a Recurring Basis (Details) - Fair Value, Recurring - Warrant [Member] ¥ in Thousands	Dec. 31, 2021 CNY (¥)
Summary of significant accounting policies
Warrant liability	¥ 66,347
Level 3
Summary of significant accounting policies
Warrant liability	¥ 66,347

Fair value of financial obligations, including, but not limited to, debt instruments, derivative liabilities, federal funds purchased and sold under agreements to repurchase, securities loaned or sold under agreements to repurchase, financial instruments sold not yet purchased, guarantees, line of credit, loans and notes payable, servicing liability, and trading liabilities.

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant