Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Oct. 03, 2015	Sep. 27, 2014	Sep. 28, 2013
Income Statement [Abstract]
Net sales	$ 802,460	$ 794,639	$ 810,126
Cost of sales	467,061	481,249	487,855
Gross profit	335,399	313,390	322,271
Operating expenses:
Research and development	81,455	79,070	82,785
Selling, general and administrative	149,829	154,030	149,513
Gain on business combination	(1,316)	0	0
Impairment of investment	2,017	0	0
Amortization of intangible assets	2,667	3,424	5,074
Total operating expenses	234,652	236,524	237,372
Income from operations	100,747	76,866	84,899
Other income (expense):
Interest and dividend income	595	397	230
Interest expense	(48)	(72)	(164)
Other-net	(1,726)	2,028	(1,469)
Total other income (expense)	(1,179)	2,353	(1,403)
Income before income taxes	99,568	79,219	83,496
Provision for income taxes	23,159	20,113	17,141
Net income	$ 76,409	$ 59,106	$ 66,355
Net income per share:
Basic (in dollars per share)	$ 3.09	$ 2.39	$ 2.75
Diluted (in dollars per share)	$ 3.06	$ 2.36	$ 2.70
Shares used in computation:
Basic, shares	24,754	24,760	24,138
Diluted, shares	24,992	25,076	24,555