Operating Segments and Geographic Information - Information on Reportable Segments (Details) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 01, 2017 USD ($)	Apr. 02, 2016 USD ($)	Apr. 01, 2017 USD ($) subsegment segment	Apr. 02, 2016 USD ($)
Information on reportable segments
Number of broad business categories (in segment) | segment			2
Net revenue	$ 196.0	$ 220.4	$ 613.3	$ 682.2
Gross profit	$ 117.0	$ 131.3	$ 366.8	$ 413.6
Gross margin (as a percent)	59.70%	59.60%	59.80%	60.60%
Operating income	$ (15.2)	$ 7.2	$ 1.6	$ 13.5
Operating margin (as a percent)	(7.80%)	3.30%	0.30%	2.00%
Segment Measures
Information on reportable segments
Net revenue	$ 196.0	$ 220.4	$ 613.3	$ 682.2
Gross profit	$ 121.9	$ 136.4	$ 382.1	$ 430.4
Gross margin (as a percent)	62.20%	61.90%	62.30%	63.10%
Operating income	$ 23.4	$ 26.2	$ 77.8	$ 85.4
Operating margin (as a percent)	11.90%	11.90%	12.70%	12.50%
Reconciling Items
Information on reportable segments
Net revenue	$ 0.0	$ 0.0	$ 0.0	$ 0.0
Gross profit	(4.9)	(5.1)	(15.3)	(16.8)
Operating income	(38.6)	(19.0)	$ (76.2)	(71.9)
Network and Service Enablement
Information on reportable segments
Number of subsegment (in subsegment) | subsegment			2
Network and Service Enablement | Segment Measures
Information on reportable segments
Net revenue	132.1	158.3	$ 444.7	497.1
Gross profit	$ 85.2	$ 100.5	$ 285.6	$ 324.7
Gross margin (as a percent)	64.50%	63.50%	64.20%	65.30%
Operating income	$ (4.4)	$ (0.1)	$ 5.7	$ 10.3
Operating margin (as a percent)	(3.30%)	(0.10%)	1.30%	2.10%
Network and Service Enablement | Network Enablement | Segment Measures
Information on reportable segments
Net revenue	$ 103.4	$ 123.1	$ 339.0	$ 377.1
Gross profit	$ 67.5	$ 80.7	$ 219.5	$ 247.0
Gross margin (as a percent)	65.30%	65.60%	64.70%	65.50%
Network and Service Enablement | Service Enablement | Segment Measures
Information on reportable segments
Net revenue	$ 28.7	$ 35.2	$ 105.7	$ 120.0
Gross profit	$ 17.7	$ 19.8	$ 66.1	$ 77.7
Gross margin (as a percent)	61.70%	56.30%	62.50%	64.80%
Optical Security and Performance Products | Segment Measures
Information on reportable segments
Net revenue	$ 63.9	$ 62.1	$ 168.6	$ 185.1
Gross profit	$ 36.7	$ 35.9	$ 96.5	$ 105.7
Gross margin (as a percent)	57.40%	57.80%	57.20%	57.10%
Operating income	$ 27.8	$ 26.3	$ 72.1	$ 75.1
Operating margin (as a percent)	43.50%	42.40%	42.80%	40.60%