Stock-Based Compensation

Stock-based compensation expense was attributable to:



	Three Months Ended				Six Months Ended
	March 30, 2019		March 31, 2018		March 30, 2019		March 31, 2018
	(In thousands)
Stock options	$	6	$	2,566	$	99	$	3,743
Restricted stock units, including performance based awards	6,620		7,729		12,343		15,194
Total	$	6,626	$	10,295	$	12,442	$	18,937

Stock-based compensation expense was recognized as follows:



	Three Months Ended				Six Months Ended
	March 30, 2019		March 31, 2018		March 30, 2019		March 31, 2018
	(In thousands)
Cost of sales	$	2,582	$	1,851	$	4,317	$	4,299
Selling, general and administrative	3,939		8,388		7,929		14,552
Research and development	105		56		196		86
Total	$	6,626	$	10,295	$	12,442	$	18,937

The Company's 2009 Stock Plan ("2009 Plan") expired as to future grants on January 26, 2019. Although the 2009 Plan was terminated, it will continue to govern all awards granted under it prior to its termination date. On March 11, 2019, the Company's stockholders approved the Company's 2019 Equity Incentive Plan ("2019 Plan") and the reservation of 4.0 million shares of common stock for issuance thereunder, plus any shares subject to stock options or similar awards granted under the 2009 Plan that expire or otherwise terminate without having been exercised in full and shares issued pursuant to awards granted that are forfeited to or repurchased by the Company.

As of March 30, 2019, an aggregate of 10.3 million shares were authorized for future issuance under the Company's stock plans, of which 5.8 million of such shares were issuable upon exercise of outstanding options and delivery of shares upon vesting of restricted stock units and 4.5 million shares of common stock were available for future grant.

Restricted Stock Units

Activity with respect to the Company's restricted stock units was as follows:



	Number of Shares		Weighted- Average Grant Date Fair Value ($)	Weighted- Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value ($)
	(In thousands)				(In thousands)
Outstanding as of September 29, 2018	3,303		30.33	1.21	97,913
Granted	1,677		24.58
Vested/Forfeited/Cancelled	(1,697	)	30.03
Outstanding as of March 30, 2019	3,283		27.55	1.62	100,282
Expected to vest as of March 30, 2019	2,598		27.70	1.42	79,376

As of March 30, 2019, unrecognized compensation expense of $45 million is expected to be recognized over a weighted average period of 1.5 years. Additionally, as of March 30, 2019, unrecognized compensation expense related to performance-based restricted stock units for which achievement of the performance criteria is not currently considered probable was $11 million.