CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Jan. 01, 2017	Jan. 03, 2016
Income Statement [Abstract]
Net sales	$ 435.5	$ 329.2
Cost of sales	159.0	141.3
Gross profit	276.5	187.9
Operating expenses:
Selling, general and administrative	90.5	69.3
Research and development costs	82.3	54.9
Amortization of intangible assets	45.5	25.4
Restructuring and severance charges	2.4	1.7
Total operating expenses	220.7	151.3
Operating income	55.8	36.6
Other expense
Interest expense, net	(25.9)	(8.2)
Other expense, net	(1.3)	(0.6)
Total other expense	(27.2)	(8.8)
Income before income taxes	28.6	27.8
Provision for income taxes	9.1	4.1
Net income	$ 19.5	$ 23.7
Earnings per share:
Basic (USD per share)	$ 0.17	$ 0.25
Diluted (USD per share)	$ 0.17	$ 0.25
Weighted-average common shares outstanding:
Basic (in shares)	114.0	95.1
Diluted (in shares)	116.3	96.5
Net income	$ 19.5	$ 23.7
Other comprehensive loss, net of tax:
Translation adjustment	(1.2)	(0.5)
Unrealized actuarial loss on pension benefits	0.0	(0.1)
Other comprehensive loss, net of tax	(1.2)	(0.6)
Total comprehensive income	$ 18.3	$ 23.1