Operating Segments and Geographic Information - Information on Reportable Segments (Details) $ in Millions	3 Months Ended
	Sep. 30, 2017 USD ($) segment subsegment	Oct. 01, 2016 USD ($)
Information on reportable segments
Number of broad business categories (in segment) | segment	2
Net revenue	$ 195.2	$ 210.8
Gross profit	$ 116.2	$ 125.1
Gross margin (as a percent)	59.50%	59.30%
Operating income (loss)	$ 10.0	$ 10.1
Operating margin (as a percent)	5.10%	4.80%
Segment Measures
Information on reportable segments
Net revenue	$ 195.2	$ 210.8
Gross profit	$ 122.5	$ 130.3
Gross margin (as a percent)	62.80%	61.80%
Operating income (loss)	$ 29.4	$ 27.5
Operating margin (as a percent)	15.10%	13.00%
Reconciling Items
Information on reportable segments
Net revenue	$ 0.0	$ 0.0
Gross profit	(6.3)	(5.2)
Operating income (loss)	$ (19.4)	(17.4)
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	$ 140.8	155.0
Gross profit	$ 91.1	$ 98.7
Gross margin (as a percent)	64.70%	63.70%
Operating income (loss)	$ 7.2	$ 4.1
Operating margin (as a percent)	5.10%	2.60%
Network and Service Enablement | Network Enablement | Segment Measures
Information on reportable segments
Net revenue	$ 111.8	$ 118.6
Gross profit	$ 70.6	$ 77.4
Gross margin (as a percent)	63.10%	65.30%
Network and Service Enablement | Service Enablement | Segment Measures
Information on reportable segments
Net revenue	$ 29.0	$ 36.4
Gross profit	$ 20.5	$ 21.3
Gross margin (as a percent)	70.70%	58.50%
Optical Security and Performance Products | Segment Measures
Information on reportable segments
Net revenue	$ 54.4	$ 55.8
Gross profit	$ 31.4	$ 31.6
Gross margin (as a percent)	57.70%	56.60%
Operating income (loss)	$ 22.2	$ 23.4
Operating margin (as a percent)	40.80%	41.90%