Long-term Debt - Interest Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 29, 2020	Mar. 31, 2019	Mar. 29, 2020	Mar. 31, 2019
Debt Instrument [Line Items]
Amortization of discount and issuance costs			$ 17.2	$ 12.7
Convertible Notes | Convertible Notes due September 1, 2023
Debt Instrument [Line Items]
Interest expense	$ 1.3	$ 1.2	3.8	2.9
Amortization of discount and issuance costs	5.8	5.5	17.2	12.7
Total interest expense	$ 7.1	$ 6.7	$ 21.0	$ 15.6