Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Jun. 25, 2016	Jun. 27, 2015	Jun. 28, 2014
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 72.2	$ 110.4	$ 46.7
Other comprehensive income:
Change in unrealized net gain on investments	(2.7)	0.8	2.8
Reclassification from accumulated other comprehensive income to interest income for accretion of non-current investments	(1.8)	(1.5)	(1.1)
Net current-period other comprehensive income	(4.5)	(0.7)	1.7
Comprehensive income	$ 67.7	$ 109.7	$ 48.4