Specific incremental costs directly attributable to a proposed or actual offering of securities which are deferred at the end of the reporting period.

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The cash outflow for cost incurred directly with the issuance of an equity security.

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Ratio applied to the conversion of stock split, for example but not limited to, one share converted to two or two shares converted to one.

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Summary of significant accounting policies - Stock split, Offering costs (Details) $ in Thousands		12 Months Ended
	Jul. 10, 2020	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jul. 24, 2020 USD ($)
Subsidiary, Sale of Stock [Line Items]
Stock split ratio	110
Deferred offering costs					$ 7,300
Offering costs		$ 543	$ 7,256	$ 721
Private placement
Subsidiary, Sale of Stock [Line Items]
Offering costs		$ 600	$ 700