Japan pension plan (Details) - Japan - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Pension liability	$ 2.9	$ 3.7
Pension liability included in accrued and other current liabilities	$ 0.3	$ 0.7

Amount of liability, recognized in statement of financial position, for defined benefit pension plan, classified as current. Excludes other postretirement benefit plan.

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