Fair Value of Financial Instruments - Summary of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Millions	Mar. 31, 2017	Jun. 30, 2016
Cash and cash equivalents:
Money market funds	$ 77.2	$ 121.0
Other current assets:
Available-for-sale securities	0.1	0.1
Other non-current assets:
Available-for-sale securities	49.8	35.5
Total assets as of period end	127.1	156.6
Liabilities
Contingent consideration obligations:	6.0	5.5
Total liabilities as of period end	6.0	5.5
Money market deposit account	22.3	91.0
Level 1
Cash and cash equivalents:
Money market funds	77.2	121.0
Other current assets:
Available-for-sale securities	0.1	0.1
Other non-current assets:
Available-for-sale securities	48.7	34.4
Total assets as of period end	126.0	155.5
Liabilities
Contingent consideration obligations:	0.0	0.0
Total liabilities as of period end	0.0	0.0
Level 2
Cash and cash equivalents:
Money market funds	0.0	0.0
Other current assets:
Available-for-sale securities	0.0	0.0
Other non-current assets:
Available-for-sale securities	0.0	0.0
Total assets as of period end	0.0	0.0
Liabilities
Contingent consideration obligations:	0.0	0.0
Total liabilities as of period end	0.0	0.0
Level 3
Cash and cash equivalents:
Money market funds	0.0	0.0
Other current assets:
Available-for-sale securities	0.0	0.0
Other non-current assets:
Available-for-sale securities	1.1	1.1
Total assets as of period end	1.1	1.1
Liabilities
Contingent consideration obligations:	6.0	5.5
Total liabilities as of period end	$ 6.0	$ 5.5