Segment and Related Information - Schedule of Segment Performance Based on Income (Loss) before Interest Income and Other Income and Expense (Detail) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Revenues	$ 216.8	$ 187.9	[1]	$ 419.1	$ 366.7	[1]
Depreciation and amortization	18.0	13.1		36.3	26.3	[1]
Segment operating income (loss)	6.1	6.3	[1]	7.3	90.3	[1]
Diagnostics [Member]
Segment Reporting Information [Line Items]
Revenues	203.0	173.1		392.0	340.5
Depreciation and amortization	16.7	11.7		33.7	23.5
Segment operating income (loss)	28.4	36.5		56.0	67.0
Other [Member]
Segment Reporting Information [Line Items]
Revenues	13.8	14.8		27.1	26.2
Depreciation and amortization	1.3	1.4		2.6	2.8
Segment operating income (loss)	$ (22.3)	$ (30.2)		$ (48.7)	$ 23.3

[1] Amounts adjusted due to the adoption of Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (Topic 606). See Note 1 to the financial statements contained in Part I, Item 1 of this report for additional information.