Share-Based Compensation - Schedule of Share-Based Compensation Recognized in Consolidated Statements of Operations (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total share-based compensation expense	$ 7.6	$ 12.5	$ 23.9	$ 31.6
Molecular Diagnostic Testing Expense
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total share-based compensation expense	0.2	0.2	0.7	0.7
Pharmaceutical and Clinical Services Expense
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total share-based compensation expense	0.1	0.1	0.3	0.4
Research And Development Expense
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total share-based compensation expense	1.3	1.2	4.1	3.2
Selling, General, and Administrative Expenses
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total share-based compensation expense	$ 6.0	$ 11.0	$ 18.8	$ 27.3