Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Oct. 01, 2016	Oct. 03, 2015	Sep. 27, 2014
Income Statement [Abstract]
Net sales	$ 857,385	$ 802,460	$ 794,639
Cost of sales	475,993	467,061	481,249
Gross profit	381,392	335,399	313,390
Operating expenses:
Research and development	81,801	81,455	79,070
Selling, general and administrative	169,138	149,829	154,030
Gain on business combination	0	(1,316)	0
Impairment of investment	0	2,017	0
Amortization of intangible assets	2,839	2,667	3,424
Total operating expenses	253,778	234,652	236,524
Income from operations	127,614	100,747	76,866
Other income (expense):
Interest and dividend income	1,143	595	397
Interest expense	(1,346)	(48)	(72)
Other—net	(4,515)	(1,726)	2,028
Total other income (expense), net	(4,718)	(1,179)	2,353
Income before income taxes	122,896	99,568	79,219
Provision for income taxes	35,394	23,159	20,113
Net income	$ 87,502	$ 76,409	$ 59,106
Net income per share:
Basic (in dollars per share)	$ 3.62	$ 3.09	$ 2.39
Diluted (in dollars per share)	$ 3.58	$ 3.06	$ 2.36
Shares used in computation:
Basic (shares)	24,142	24,754	24,760
Diluted (shares)	24,415	24,992	25,076