Stock-Based Compensation

Stock-based compensation expense was attributable to:



	Year Ended
	September 30, 2017		October 1, 2016		October 3, 2015
	(In thousands)
Stock options	$	1,640	$	3,943	$	9,894
Restricted stock units, including performance-based awards	36,280		22,964		10,759
Total	$	37,920	$	26,907	$	20,653

Stock-based compensation expense was recognized as follows:



	Year Ended
	September 30, 2017		October 1, 2016		October 3, 2015
	(In thousands)
Cost of sales	$	8,959	$	7,350	$	6,611
Selling, general & administrative	28,169		18,903		13,859
Research & development	792		654		183
Total	$	37,920	$	26,907	$	20,653

Stock Options

The Company's stock option plans provide employees the right to purchase common stock at the fair market value of such shares on the grant date. The Company recognizes compensation expense for such awards ratably over the vesting period, which is generally four to five years. The contractual term of all options is ten years, at which time such options expire.

The Company did not grant any stock options in 2017 and only granted 1,000 stock options in 2016. Assumptions used to estimate the fair value of stock options granted in 2015 were as follows:




	October 3, 2015
Volatility	52.9	%
Risk-free interest rate	1.6	%
Dividend yield	—
Expected life of options	5.0

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 27, 2014	8,181		12.90	5.30	93,767
Granted	567		24.48
Exercised/Cancelled/Forfeited/Expired	(1,715	)	16.13
Outstanding as of October 3, 2015	7,033		13.05	4.94	53,938
Granted	1		23.77
Exercised/Cancelled/Forfeited/Expired	(1,520	)	14.13
Outstanding as of October 1, 2016	5,514		12.75	4.10	81,659
Exercised/Cancelled/Forfeited/Expired	(1,946	)	14.44
Outstanding as of September 30, 2017	3,568		11.83	3.82	90,327
Exercisable as of September 30, 2017	3,469		11.51	3.73	88,950

The weighted-average grant date fair value of stock options granted during 2015 was $12.46. 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 their options at the Company's closing stock price on the date indicated. The total intrinsic value of stock options exercised was $41.4 million for 2017, $15.9 million for 2016 and $16.2 million for 2015.

The following table summarizes information regarding stock options outstanding at September 30, 2017:



Options Outstanding				Options Vested and Exercisable
Range of Weighted Exercise Prices	Number Outstanding	Weighted Average Remaining Contractual Life (Years)	Weighted Average Exercise Price ($)	Number Exercisable	Weighted Average Exercise Price ($)
	(In thousands)			(In thousands)
$1.80-$8.81	1,922	2.90	7.88	1,920	7.88
$8.82-$11.57	455	3.55	11.08	455	11.08
$11.58-$15.47	194	0.92	12.02	194	12.02
$15.48-$23.76	555	5.55	15.87	536	15.80
$23.77-$24.65	442	7.20	24.61	364	24.60
$1.80-$24.65	3,568	3.82	11.83	3,469	11.51

Restricted Stock Units

The Company grants restricted stock units to executive officers, directors and certain management employees. These units vest over periods ranging from one to four years or based upon achievement of specified performance criteria and are automatically exchanged for shares of common stock at the vesting date. Compensation expense associated with these units is recognized ratably over the vesting period.

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



	Number of Shares		Weighted Grant-Date Fair Value Per Share ($)	Weighted-Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value ($)
	(In thousands)				(In thousands)
Outstanding as of September 27, 2014	2,341		13.29	2.01	56,064
Granted	966		23.42
Vested/Forfeited/Cancelled	(328	)	13.79
Outstanding as of October 3, 2015	2,979		16.52	1.52	59,843
Granted	1,698		23.22
Vested/Forfeited/Cancelled	(679	)	15.33
Outstanding as of October 1, 2016	3,998		19.57	1.35	110,183
Granted	1,378		34.11
Vested/Forfeited/Cancelled	(2,017	)	16.20
Outstanding as of September 30, 2017	3,359		27.56	1.51	124,800
Expected to vest as of September 30, 2017	2,834		26.73	1.44	105,288

The vest-date fair value of restricted stock units vested was $53.2 million for 2017, $10.4 million for 2016 and $6.7 million for 2015. As of September 30, 2017, unrecognized compensation expense of $41.9 million is expected to be recognized over a weighted average period of 1.5 years. Additionally, as of September 30, 2017, unrecognized compensation expense related to performance-based restricted stock units for which achievement of vesting criteria is not currently considered probable was $9.4 million.