Fair value measurements (Tables)

12 Months Ended

Dec. 31, 2019

Fair Value Disclosures [Abstract]

Summary of Reconciliation of Contingent Consideration Liabilities Measured at Fair Value

The following table is a reconciliation of the beginning and ending balance of the contingent consideration liabilities measured at fair value using significant unobservable inputs (Level 3) during the years ended December 31, 2019 and 2018.

(in millions)
Balance at December 31, 2017	$	12.3
Expense included in earnings	3.1
Settlements	(3.4		)
Additions due to acquisition	48.0
Balance at December 31, 2018	$	60.0
Expense included in earnings	24.8
Milestone achievement - asset acquisition	10.0
Measurement period adjustment	1.5
Settlements	(67.1		)
Balance at December 31, 2019	$	29.2