CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Millions	Total	Common Stock	Additional Paid-In Capital	Accumulated Deficit	Accumulated Other Comprehensive Loss
Balance at the beginning of the period (in shares) at Jun. 30, 2018		226,700
Balance at the beginning of the period at Jun. 30, 2018	$ 734.9	$ 0.2	$ 70,216.2	$ (69,378.6)	$ (102.9)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(2.3)			(2.3)
Other comprehensive income (loss)	(24.5)				(24.5)
Shares issued under employee stock plans, net of tax (in shares)		2,200
Shares issued under employee stock plans, net of tax	(7.3)		(7.3)
Stock-based compensation	17.9		17.9
Repurchase of common stock (in shares)		(900)
Repurchase of common stock	(8.5)			(8.5)
Other	(0.1)			(0.1)
Balance at the end of the period (in shares) at Dec. 29, 2018		228,000
Balance at the end of the period at Dec. 29, 2018	710.1	$ 0.2	70,226.8	(69,389.5)	(127.4)
Balance at the beginning of the period (in shares) at Sep. 29, 2018		228,200
Balance at the beginning of the period at Sep. 29, 2018	709.6	$ 0.2	70,218.6	(69,394.1)	(115.1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	13.0			13.0
Other comprehensive income (loss)	(12.4)				(12.4)
Shares issued under employee stock plans, net of tax (in shares)		700
Shares issued under employee stock plans, net of tax	(1.5)		(1.5)
Stock-based compensation	9.7		9.7
Repurchase of common stock (in shares)		(900)
Repurchase of common stock	(8.5)			(8.5)
Other	0.2			0.1	0.1
Balance at the end of the period (in shares) at Dec. 29, 2018		228,000
Balance at the end of the period at Dec. 29, 2018	710.1	$ 0.2	70,226.8	(69,389.5)	(127.4)
Balance at the beginning of the period (in shares) at Jun. 29, 2019		228,800
Balance at the beginning of the period at Jun. 29, 2019	725.8	$ 0.2	70,244.7	(69,384.5)	(134.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	34.8			34.8
Other comprehensive income (loss)	2.1				2.1
Shares issued under employee stock plans, net of tax (in shares)		2,200
Shares issued under employee stock plans, net of tax	(12.6)		(12.6)
Stock-based compensation	$ 21.9		21.9
Repurchase of common stock (in shares)	(763)	(800)
Repurchase of common stock	$ (10.7)			(10.7)
Balance at the end of the period (in shares) at Dec. 28, 2019		230,200
Balance at the end of the period at Dec. 28, 2019	764.3	$ 0.2	70,254.0	(69,357.4)	(132.5)
Balance at the beginning of the period (in shares) at Sep. 28, 2019		230,400
Balance at the beginning of the period at Sep. 28, 2019	708.1	$ 0.2	70,245.4	(69,376.2)	(161.3)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	28.0			28.0
Other comprehensive income (loss)	28.8				28.8
Shares issued under employee stock plans, net of tax (in shares)		500
Shares issued under employee stock plans, net of tax	(2.9)		(2.9)
Stock-based compensation	$ 11.5		11.5
Repurchase of common stock (in shares)	(659)	(700)
Repurchase of common stock	$ (9.2)			(9.2)
Balance at the end of the period (in shares) at Dec. 28, 2019		230,200
Balance at the end of the period at Dec. 28, 2019	$ 764.3	$ 0.2	$ 70,254.0	$ (69,357.4)	$ (132.5)