Stock-based compensation - Stock Options and RSUs (Details)	6 Months Ended
Jun. 30, 2021 shares
Stock Options
Number of Shares
Beginning Balance (in shares)	2,096,917
Granted (in shares)	53,487
Exercised/Converted (in shares)	(398,627)
Cancelled/Forfeited (in shares)	(17,393)
Ending Balance (in shares)	1,734,384
RSUs
Number of Units
Beginning Balance (in shares)	3,621,681
Granted (in shares)	89,744
Exercised/Converted (in shares)	(999,459)
Cancelled/Forfeited (in shares)	(246,851)
Ending Balance (in shares)	2,465,115

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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No definition available.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

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Gross number of share options (or share units) granted during the period.

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No definition available.

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Number of options outstanding, including both vested and non-vested options.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Number of share options (or share units) exercised during the current period.

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