Balance Sheet Components (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 02, 2016	Mar. 28, 2015	Apr. 02, 2016	Mar. 28, 2015	Jun. 27, 2015
Accounts receivable allowance
Accounts receivable allowance	$ 1.1		$ 1.1		$ 1.2
Inventories
Finished goods	51.3		51.3		60.1
Work in process	24.8		24.8		23.4
Raw materials and purchased parts	31.1		31.1		16.2
Inventories, net	107.2		107.2		99.7
Inventory written off	9.6	$ 1.4	10.7	$ 3.4
Prepayments and other current assets
Prepayments	29.7		29.7		20.4
Advances to contract manufacturers	8.2		8.2		9.5
Due from Viavi, net	3.3		3.3		0.0
Other current assets	17.5		17.5		16.2
Prepayments and other current assets	58.7		58.7		46.1
Property, plant and equipment
Property, plant and equipment, gross	490.8		490.8		416.2
Less: Accumulated depreciation	(322.7)		(322.7)		(273.0)
Property, plant and equipment, net	168.1		168.1		143.2
Other current liabilities
Restructuring accrual and related charges	3.8		3.8		3.2
Warranty accrual	1.8		1.8		2.8
Others	4.2		4.2		5.4
Other current liabilities	9.8		9.8		11.4
Other non-current liabilities
Asset retirement obligation	2.3		2.3		1.8
Pension and related accruals	2.3		2.3		2.1
Deferred rent	1.8		1.8		1.7
Restructuring accrual and related charges	0.0		0.0		1.7
Other non-current liabilities	2.3		2.3		2.5
Total other non-current liabilities	8.7		8.7		9.8
Land
Property, plant and equipment
Property, plant and equipment, gross	5.9		5.9		5.9
Buildings and improvements
Property, plant and equipment
Property, plant and equipment, gross	28.8		28.8		28.6
Machinery and equipment
Property, plant and equipment
Property, plant and equipment, gross	340.3		340.3		326.4
Furniture and fixtures and software
Property, plant and equipment
Property, plant and equipment, gross	31.8		31.8		8.0
Leasehold improvements
Property, plant and equipment
Property, plant and equipment, gross	27.9		27.9		20.5
Construction in progress
Property, plant and equipment
Property, plant and equipment, gross	$ 56.1		$ 56.1		$ 26.8