Consolidated Statements of Operations and Comprehensive Income - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Sep. 27, 2015	Sep. 28, 2014	Sep. 29, 2013
Income Statement [Abstract]
Net sales	$ 1,245.6	$ 1,138.3	$ 975.9
Cost of sales	561.3	526.8	418.7
Gross profit	684.3	611.5	557.2
Operating expenses:
Selling, general and administrative	249.5	241.0	202.5
Research and development costs	200.3	192.0	170.6
Amortization of intangible assets	96.5	92.8	84.8
Restructuring and severance charges	15.4	31.5	9.9
Total operating expenses	561.7	557.3	467.8
Operating income	122.6	54.2	89.4
Interest Income (Expense), Net	(27.3)	(27.8)	(30.2)
Other income (expenses):
Other, net	1.6	(2.5)	(3.1)
Total other expense	(25.7)	(30.3)	(33.3)
Income (loss) before income taxes	96.9	23.9	56.1
Income Tax Expense (Benefit)	12.3	0.8	12.4
Net income (loss)	$ 84.6	$ 23.1	$ 43.7
Earnings (loss) per share:
Basic	$ 0.90	$ 0.25	$ 0.49
Diluted	$ 0.88	$ 0.24	$ 0.48
Weighted-average common shares outstanding:
Basic	94.2	92.9	89.5
Diluted	95.9	94.5	91.3
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Translation adjustment	$ (1.6)	$ (0.5)	$ 0.9
Unrealized actuarial loss on pension benefits	(0.3)	(0.7)	(0.2)
Other comprehensive income (loss)	(1.9)	(1.2)	0.7
Total comprehensive income (loss)	$ 82.7	$ 21.9	$ 44.4