CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2013	Apr. 01, 2012	Mar. 31, 2013	Apr. 01, 2012
Income Statement [Abstract]
Net sales	$ 235,333	$ 249,306	$ 482,931	$ 490,226
Cost of sales	101,868	117,438	206,893	232,622
Gross profit	133,465	131,868	276,038	257,604
Operating expenses:
Selling, general and administrative	52,316	51,971	103,669	106,687
Research and development costs	41,956	42,188	85,132	81,789
Amortization of intangible assets	21,110	26,472	42,820	51,334
Restructuring and severance charges	6,261	119	7,111	7,344
Total operating expenses	121,643	120,750	238,732	247,154
Operating income (loss)	11,822	11,118	37,306	10,450
Other income (expenses):
Interest expense, net	(7,744)	(10,194)	(16,105)	(22,033)
Other, net	(3,603)	(1,035)	(3,549)	(33,439)
Total other expense	(11,347)	(11,229)	(19,654)	(55,472)
Income (loss) before income taxes	475	(111)	17,652	(45,022)
Provision for income taxes	3,380	4,681	6,343	4,372
Net income (loss)	(2,905)	(4,792)	11,309	(49,394)
Earnings (loss) per share:
Basic	$ (0.03)	$ (0.06)	$ 0.13	$ (0.58)
Diluted	$ (0.03)	$ (0.06)	$ 0.12	$ (0.58)
Weighted-average common shares outstanding:
Basic	89,405	85,645	88,970	85,435
Diluted	89,405	85,645	90,538	85,435
Other comprehensive income (loss), net of tax:
Translation adjustment, net of tax	(7)	(176)	179	(115)
Unrealized actuarial loss on pension benefits, net of tax	(42)	0	(86)	0
Other comprehensive income (loss)	(49)	(176)	93	(115)
Total comprehensive income (loss)	$ (2,954)	$ (4,968)	$ 11,402	$ (49,509)