Summary of significant accounting policies - Income Taxes (Details) - USD ($)	3 Months Ended	9 Months Ended
Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Summary of significant accounting policies
Interest or penalties related to unrecognized tax benefits	$ 0	$ 0	$ 0	$ 0

Amount of expense for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=121826272&loc=d3e32718-109319

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration