CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Sep. 28, 2019	Sep. 29, 2018	Sep. 30, 2017
Income Statement [Abstract]
Revenue	$ 1,260,823	$ 1,137,008	$ 992,526
Cost of revenue	733,480	647,700	536,461
Gross profit	527,343	489,308	456,065
Operating expenses
Research and development	171,174	142,109	124,394
Sales and marketing	247,599	270,869	270,162
General and administrative	102,871	85,205	77,118
Total operating expenses	521,644	498,183	471,674
Operating income (loss)	5,699	(8,875)	(15,609)
Other income (expense), net
Interest income	4,349	731	120
Interest expense	(2,499)	(5,242)	(4,380)
Other income (expense), net	(8,625)	(1,162)	3,361
Total other expense, net	(6,775)	(5,673)	(899)
Loss before provision for (benefit from) income taxes	(1,076)	(14,548)	(16,508)
Provision for (benefit from) income taxes	3,690	1,056	(2,291)
Net loss	(4,766)	(15,604)	(14,217)
Net loss attributable to common stockholders, basic and diluted:	$ (4,766)	$ (15,604)	$ (14,217)
Net loss per share attributable to common stockholders, basic and diluted (in dollars per share)	$ (0.05)	$ (0.24)	$ (0.25)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted (in shares)	103,783,006	65,706,215	56,314,546
Total comprehensive loss
Net loss	$ (4,766)	$ (15,604)	$ (14,217)
Change in foreign currency translation adjustment	1,613	488	(2,486)
Comprehensive loss	$ (3,153)	$ (15,116)	$ (16,703)