CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Apr. 01, 2018	Apr. 02, 2017	Apr. 01, 2018	Apr. 02, 2017
Income Statement [Abstract]
Net sales	$ 492.2	$ 442.9	$ 960.9	$ 878.4
Cost of sales (excluding amortization of intangible assets below)	201.9	158.8	382.0	317.8
Gross profit	290.3	284.1	578.9	560.6
Operating expenses
Selling, general and administrative	100.8	75.8	185.1	166.2
Research and development costs	92.7	86.9	181.8	169.2
Amortization of intangible assets	42.2	46.5	92.4	92.1
Restructuring, severance and facilities charges	3.1	5.8	8.6	8.2
Total operating expenses	238.8	215.0	467.9	435.7
Operating income	51.5	69.1	111.0	124.9
Other expense
Interest expense, net	(22.8)	(25.9)	(44.4)	(51.8)
Other expense, net	(0.8)	(0.3)	(4.4)	(1.6)
Total other expense	(23.6)	(26.2)	(48.8)	(53.4)
Income before income taxes	27.9	42.9	62.2	71.5
Provision for income taxes	15.6	1.7	2.0	10.9
Net income	$ 12.3	$ 41.2	$ 60.2	$ 60.6
Earnings per share
Basic (USD per share)	$ 0.10	$ 0.36	$ 0.51	$ 0.53
Diluted (USD per share)	$ 0.10	$ 0.35	$ 0.50	$ 0.52
Weighted-average common shares outstanding:
Basic (in shares)	117.4	114.7	117.2	114.4
Diluted (in shares)	119.6	117.0	119.3	116.6
Net income	$ 12.3	$ 41.2	$ 60.2	$ 60.6
Other comprehensive income (loss), net of taxes
Currency translation adjustment	0.9	0.3	1.4	(0.9)
Other comprehensive income (loss), net of taxes	0.9	0.3	1.4	(0.9)
Total comprehensive income	$ 13.2	$ 41.5	$ 61.6	$ 59.7