Stock-Based Compensation Plans

The Company’s equity incentive plans are broad-based, long-term retention programs that cover employees, consultants and non-employee directors of the Company. These plans are intended to attract and retain talented employees, consultants and non-employee directors and to provide such persons with a proprietary interest in the Company.

Stock-Based Compensation

The following table summarizes stock-based compensation expense related to stock awards granted under the Company’s equity incentive plans and rights to acquire stock granted under the Company’s Employee Stock Purchase Plan (ESPP):



	Three Months Ended				Six Months Ended
(In thousands)	September 30, 2017		October 1, 2016		September 30, 2017		October 1, 2016
Stock-based compensation included in:
Cost of revenues	$	2,147	$	1,930	$	4,297	$	4,049
Research and development	20,096		16,529		37,562		31,649
Selling, general and administrative	14,129		11,343		26,549		23,508
	$	36,372	$	29,802	$	68,408	$	59,206

Employee Stock Option Plans

The types of awards allowed under the 2007 Equity Incentive Plan (2007 Equity Plan) include incentive stock options, non-qualified stock options, restricted stock units (RSUs), restricted stock and stock appreciation rights. To date, the Company has issued a mix of non-qualified stock options and RSUs under the 2007 Equity Plan; however, there was no issuance of stock options during the first six months of fiscal year 2018 and the entire fiscal year 2017. The Company's stock-based compensation expenses related to options during the first six months of fiscal year 2018 and the number of options outstanding as of September 30, 2017 were not material. On August 9, 2017, the stockholders approved an amendment to increase the authorized number of shares reserved for issuance under the 2007 Equity Plan by 1.9 million shares. As of September 30, 2017, 11.4 million shares remained available for grant under the 2007 Equity Plan.

The total pre-tax intrinsic value of options exercised during the three and six months ended September 30, 2017 was $465 thousand and $3.2 million, respectively. The total pre-tax intrinsic value of options exercised during the three and six months ended October 1, 2016 was $8.8 million and $21.4 million, respectively. This intrinsic value represents the difference between the exercise price and the fair market value of the Company’s common stock on the date of exercise.

RSU Awards

A summary of the Company’s RSU activity and related information is as follows:



	RSUs Outstanding
(Shares in thousands)	Number of Shares		Weighted-Average Grant-Date Fair Value Per Share
April 2, 2016	6,619		$	40.74
Granted	3,398		$	44.38
Vested	(2,619	)	$	39.49
Cancelled	(410	)	$	41.63
April 1, 2017	6,988		$	42.93
Granted	3,262		$	59.89
Vested	(2,288	)	$	41.99
Cancelled	(314	)	$	46.76
September 30, 2017	7,648		$	49.91

The estimated fair values of RSU awards were calculated based on the market price of Xilinx common stock on the date of grant, reduced by the present value of dividends expected to be paid on Xilinx common stock prior to vesting. The per share weighted-average fair value of RSUs granted during the second quarter of fiscal year 2018 was $59.99 ($42.89 for the second quarter of fiscal year 2017), and for the first six months of fiscal year 2018 was $59.89 ($42.87 for the first six months of fiscal year 2017), which were calculated based on estimates at the date of grant using the following weighted-average assumptions:



	Three Months Ended				Six Months Ended
	September 30, 2017		October 1, 2016		September 30, 2017		October 1, 2016
Risk-free interest rate	1.7	%	0.8	%	1.7	%	0.8	%
Dividend yield	2.2	%	2.9	%	2.2	%	2.9	%

For the majority of RSUs granted, the number of shares of common stock issued on the date the RSU awards vest is net of the minimum statutory withholding requirements that the Company pays in cash to the appropriate taxing authorities on behalf of its employees.

During the second quarter and the first six months of fiscal year 2018, the Company realized excess tax benefits of $6.3 million and $17.9 million, respectively. During the second quarter and the first six months of fiscal year 2017, the Company realized excess tax benefits of $2.9 million and $9.7 million, respectively. These benefits were recorded in the condensed consolidated statements of income as a component of the provision for income taxes.

Employee Stock Purchase Plan

Under the ESPP, shares are only issued during the second and fourth quarters of each fiscal year. Employees purchased 355 thousand shares for $16.9 million during the second quarter of fiscal year 2018 and 446 thousand shares for $15.0 million during the second quarter of fiscal year 2017. The per-share weighted-average fair value of stock purchase rights granted under the ESPP during the second quarter of fiscal years 2018 and 2017 was $16.46 and $11.64, respectively. The fair values of stock purchase plan rights granted in the second quarter of fiscal years 2018 and 2017 were estimated using the Black-Scholes option pricing model at the date of grant using the following assumptions:



	2018		2017
Expected life of options (years)	1.25		1.25
Expected stock price volatility	0.28		0.23
Risk-free interest rate	1.3	%	0.5	%
Dividend yield	2.2	%	2.6	%

The next scheduled purchase under the ESPP is in the fourth quarter of fiscal year 2018. On August 9, 2017, the stockholders approved an amendment to increase the authorized number of shares reserved for issuance under the ESPP by 2.0 million shares. As of September 30, 2017, 9.9 million shares were available for future issuance under the ESPP.