Equity Plans

As of May 31, 2018, 127 million shares of our common stock were available for future awards under our equity plans, including 33 million shares approved for issuance under our employee stock purchase plan ("ESPP").

Employee Stock Purchase Plan

Our ESPP was approved by shareholders at our 2017 Annual Shareholder Meeting and will be offered to substantially all employees beginning in August 2018. The ESPP permits eligible employees to purchase shares of our common stock through payroll deductions of up to 10% of their eligible compensation, subject to certain limitations. The purchase price of the shares under the ESPP equals 85% of the lower of the fair market value of our common stock on either the first or last trading day of each six-month offering period.

Stock Options



	Quarter ended						Nine months ended
	May 31, 2018			June 1, 2017			May 31, 2018			June 1, 2017
Stock options granted	—			1			2			7
Weighted-average grant-date fair value per share	$	24.14		$	11.64		$	18.61		$	8.59
Average expected life in years	5.4			5.5			5.5			5.5
Weighted-average expected volatility	45		%	44		%	44		%	46		%
Weighted-average risk-free interest rate	2.8		%	2.0		%	2.2		%	1.8		%
Expected dividend yield	0.0		%	0.0		%	0.0		%	0.0		%

Restricted Stock and Restricted Stock Units ("Restricted Stock Awards")



	Quarter ended				Nine months ended
	May 31, 2018		June 1, 2017		May 31, 2018		June 1, 2017
Restricted stock award shares granted	—		—		4		8
Weighted-average grant-date fair value per share	$	53.77	$	27.75	$	42.14	$	19.10

Stock-based Compensation Expense



	Quarter ended				Nine months ended
	May 31, 2018		June 1, 2017		May 31, 2018		June 1, 2017
Stock-based compensation expense by caption
Cost of goods sold	$	20	$	24	$	62	$	66
Selling, general, and administrative	14		20		48		53
Research and development	14		13		41		39
	$	48	$	57	$	151	$	158

Stock-based compensation expense by type of award
Stock options	$	13	$	19	$	44	$	54
Restricted stock awards	35		38		107		104
	$	48	$	57	$	151	$	158

The income tax benefit related to share-based compensation was $26 million and $142 million for the third quarter and first nine months of 2018, respectively, and $17 million and $80 million for the third quarter and first nine months of 2017, respectively. The income tax benefits related to share-based compensation for the periods presented prior to the second quarter of 2018 were offset by an increase in the U.S. valuation allowance. As of May 31, 2018, $364 million of total unrecognized compensation costs for unvested awards was expected to be recognized through the third quarter of 2022, resulting in a weighted-average period of 1.3 years.