Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	Oct. 03, 2015
Income Statement [Abstract]
Net sales	$ 1,723,311	$ 857,385	$ 802,460
Cost of sales	973,042	475,993	467,061
Gross profit	750,269	381,392	335,399
Operating expenses:
Research and development	119,166	81,801	81,455
Selling, general and administrative	292,084	169,138	149,829
Gain on business combination	(5,416)	0	(1,316)
Impairment of assets held for sale	2,916	0	0
Impairment of investment	0	0	2,017
Amortization of intangible assets	16,024	2,839	2,667
Total operating expenses	424,774	253,778	234,652
Income from operations	325,495	127,614	100,747
Other income (expense):
Interest income	1,090	1,143	595
Interest expense	(34,362)	(1,346)	(48)
Other—net	9,832	(4,515)	(1,726)
Total other expense, net	(23,440)	(4,718)	(1,179)
Income from continuing operations before income taxes	302,055	122,896	99,568
Provision for income taxes	93,411	35,394	23,159
Net income from continuing operations	208,644	87,502	76,409
Loss from discontinued operations, net of income taxes	(1,522)	0	0
Net income	$ 207,122	$ 87,502	$ 76,409
Basic net income (loss) per share:
Income per share from continuing operations (in dollars per share)	$ 8.52	$ 3.62	$ 3.09
Loss per share from discontinued operations, net of income taxes (in dollars per share)	(0.06)	0.00	0.00
Net income per share (in dollars per share)	8.46	3.62	3.09
Diluted net income (loss) per share:
Income per share from continuing operations (in dollars per share)	8.42	3.58	3.06
Loss per share from discontinued operations, net of income taxes (in dollars per share)	(0.06)	0.00	0.00
Net income per share (in dollars per share)	$ 8.36	$ 3.58	$ 3.06
Shares used in computation:
Basic (shares)	24,487	24,142	24,754
Diluted (shares)	24,777	24,415	24,992