Stock-Based Compensation

Stock-based compensation expense was attributable to:



	Three Months Ended				Six Months Ended
	March 31, 2018		April 1, 2017		March 31, 2018		April 1, 2017
	(In thousands)
Stock options	$	2,566	$	380	$	3,743	$	930
Restricted stock units, including performance based awards	7,729		7,262		15,194		18,689
Total	$	10,295	$	7,642	$	18,937	$	19,619

Stock-based compensation expense was recognized as follows:



	Three Months Ended				Six Months Ended
	March 31, 2018		April 1, 2017		March 31, 2018		April 1, 2017
	(In thousands)
Cost of sales	$	1,851	$	2,035	$	4,299	$	4,899
Selling, general and administrative	8,388		5,376		14,552		14,216
Research and development	56		231		86		504
Total	$	10,295	$	7,642	$	18,937	$	19,619

During the second quarter of 2018, the Company's stockholders approved the reservation of an additional 1.8 million shares of common stock for future issuance under the Company's 2009 Incentive Plan. As of March 31, 2018, an aggregate of 10.7 million shares were authorized for future issuance under the Company's stock plans, of which 6.8 million of such shares were issuable upon exercise of outstanding options and delivery of shares upon vesting of restricted stock units and 3.9 million shares of common stock were available for future grant.

Stock Options

Stock option activity was as follows:



	Number of Shares		Weighted- Average Exercise Price ($)	Weighted- Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value of In-The-Money Options ($)
	(In thousands)				(In thousands)
Outstanding as of September 30, 2017	3,568		11.83	3.82	90,327
Granted	200		38.45
Exercised/Cancelled/Forfeited/Expired	(337	)	11.41
Outstanding as of March 31, 2018	3,431		13.42	3.86	53,074
Vested and expected to vest as of March 31, 2018	3,429		13.42	3.86	53,059
Exercisable as of March 31, 2018	3,234		12.11	3.55	52,867

The aggregate intrinsic value in the preceding table represents the total pre-tax intrinsic value of in-the-money options that would have been received by the option holders had all option holders exercised such options at the Company's closing stock price on the date indicated.

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 30, 2017	3,359		27.56	1.51	124,800
Granted	793		34.85
Vested/Forfeited/Cancelled	(792	)	26.30
Outstanding as of March 31, 2018	3,360		29.58	1.44	95,080
Expected to vest as of March 31, 2018	2,574		28.72	1.40	72,842

As of March 31, 2018, unrecognized compensation expense of $43 million is expected to be recognized over a weighted average period of 1.5 years. Additionally, as of March 31, 2018, unrecognized compensation expense related to performance-based restricted stock units for which achievement of the performance criteria is not currently considered probable was $20 million.