Stock-based compensation - Restricted Stock Units - Narrative (Details) - 2020 Equity Incentive Plan shares in Thousands, $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2021 USD ($) shares	Sep. 30, 2021 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period for recognition		2 years 11 months 19 days
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued upon vesting (in shares) \| shares	80
Shares withheld (in shares) \| shares	80
Tax withholding obligation \| $	$ 2.1
Unrecognized compensation expense, excluding options \| $	$ 13.6	$ 13.6
Period for recognition		1 year 10 months 24 days

Amount of decrease to equity for grantee's tax withholding obligation for award under share-based payment arrangement.

No definition available.

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- Definition

Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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- Definition

Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

+ References

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- Definition

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.

+ References

No definition available.

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- Definition

Number of shares issued under share-based payment arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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- Definition

Number of shares used to settle grantee's tax withholding obligation for award under share-based payment arrangement.

+ References

No definition available.

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