CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands, shares in Millions	3 Months Ended		6 Months Ended
	Apr. 03, 2016	Mar. 29, 2015	Apr. 03, 2016	Mar. 29, 2015
Income Statement [Abstract]
Net sales	$ 444,300	$ 296,200	$ 773,500	$ 599,800
Cost of sales	243,700	126,900	385,000	262,400
Gross profit	200,600	169,300	388,500	337,400
Operating expenses:
Selling, general and administrative	113,700	61,000	183,000	121,100
Research and development costs	87,800	46,400	142,700	94,000
Amortization of intangible assets	45,300	22,700	70,685	46,273
Restructuring and severance charges	51,700	3,800	53,400	10,900
Total operating expenses	298,500	133,900	449,800	272,300
Operating income	(97,900)	35,400	(61,300)	65,100
Other expenses
Interest expense, net	(38,000)	(5,900)	(46,200)	(12,100)
Other expense, net	(77,800)	(400)	(78,400)	(800)
Total other expense	(115,800)	(6,300)	(124,600)	(12,900)
Income (loss) before income taxes	(213,700)	29,100	(185,900)	52,200
Provision (benefit) for income taxes	(1,700)	4,200	2,400	7,600
Net income (loss)	$ (212,000)	$ 24,900	$ (188,300)	$ 44,600
Earnings (loss) per share:
Basic (USD per share)	$ (1.93)	$ 0.26	$ (1.85)	$ 0.47
Diluted (USD per share)	$ (1.93)	$ 0.26	$ (1.85)	$ 0.47
Weighted-average common shares outstanding:
Basic (in shares)	109.6	94.0	102.0	94.0
Diluted (in shares)	109.6	95.3	102.0	95.2
Net income (loss)	$ (212,000)	$ 24,900	$ (188,300)	$ 44,600
Other comprehensive income (loss), net of tax:
Translation adjustment	1,900	(2,400)	2,600	(1,900)
Unrealized actuarial loss on pension benefits	(100)	(100)	(100)	(100)
Other comprehensive income (loss), net of tax	1,800	(2,500)	2,500	(2,000)
Total comprehensive income (loss)	$ (210,200)	$ 22,400	$ (185,800)	$ 42,600