Summary of significant accounting policies - Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Summary of significant accounting policies
Income tax benefit recognition threshold	50.00%
Unrecognized tax benefit or accrued interest and penalties	$ 0	$ 0	$ 0

Amount accrued 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
-Topic 740
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 15
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482685/740-10-50-15

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant