Stock-based compensation (Tables)

6 Months Ended

Mar. 30, 2019

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of Stock Option Activity

The summary of the Company’s stock option activity is as follows:

	Number of Options		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term	Aggregate Intrinsic Value
					(in years)	(in thousands)
Outstanding at September 29, 2018	48,504,182		$	10.33	6.6	$	276,959
Granted	1,214,328
Exercised	(4,794,807	)
Forfeited	(3,198,652	)
Outstanding at March 30, 2019	41,725,051		$	10.95	6.5	$	79,001
At March 30, 2019
Options exercisable	27,505,569		$	9.19	5.5	$	79,001
Options vested and expected to vest	39,490,352		$	10.75	6.4	$	79,001

Schedule of Restricted Stock Unit Activity

The summary of the Company’s unvested RSU activity is as follows:

	Number of Units		Weighted Average Grant Date Fair Value		Aggregate Intrinsic Value
					(in thousands)
Unvested at September 29, 2018	—		$	—	$	—
Granted	6,124,663
Vested	(29,575	)
Forfeited	(26,730	)
Unvested at March 30, 2019	6,068,358		$	11.46	$	62,443
At March 30, 2019
Units expected to vest	4,561,416		$	11.47	$	46,937

Schedule of Stock-based Compensation Expense

Total stock-based compensation expense by function category was as follows:

	Three Months Ended				Six Months Ended
	March 30, 2019		March 31, 2018		March 30, 2019		March 31, 2018
(In thousands)
Cost of revenue	$	218	$	51	$	403	$	107
Research and development	4,284		3,384		7,888		6,766
Sales and marketing	3,128		4,037		5,809		8,022
General and administrative	3,456		2,056		6,018		4,170
Total stock-based compensation expense	$	11,086	$	9,528	$	20,118	$	19,065