Note 9: Share-Based Compensation

Total share-based compensation expense related to the Company's stock options, RSUs, stock grant awards and the ESPP were recorded within the Consolidated Statements of Operations and Comprehensive Income as follows (in millions):



	Quarters Ended				Nine Months Ended
	September 28, 2018		September 29, 2017		September 28, 2018		September 29, 2017
Cost of revenue	$	1.7	$	1.4	$	5.1	$	4.4
Research and development	3.4		3.2		10.6		9.6
Selling and marketing	3.3		2.8		10.5		8.8
General and administrative	9.5		9.4		33.2		29.9
Share-based compensation expense before income taxes	$	17.9	$	16.8	$	59.4	$	52.7
Related income tax benefits ⁽¹⁾	3.8		5.9		12.5		18.4
Share-based compensation expense, net of taxes	$	14.1	$	10.9	$	46.9	$	34.3


⁽¹⁾	Tax benefit was calculated using the federal statutory rate of 21% and 35% for the quarters and nine months ended September 28, 2018 and September 29, 2017, respectively.

At September 28, 2018, total unrecognized share-based compensation expense, net of estimated forfeitures, related to non-vested RSUs with time-based service conditions and performance-based vesting criteria was $93.4 million, which is expected to be recognized over a weighted-average period of 1.55 years. The total intrinsic value of stock options exercised during the quarter and nine months ended September 28, 2018 was $0.2 million and $10.7 million, respectively. The Company received cash of $0.1 million and $4.4 million, respectively, during the quarter and nine months ended September 28, 2018 from the exercise of stock options. Upon option exercise, vesting of RSUs, stock grant awards or completion of a purchase under the ESPP, the Company issues new shares of common stock.

Share-based compensation expense is based on awards that are ultimately expected to vest. Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. The annualized pre-vesting forfeiture rate for RSUs and stock options was estimated to be 5% and 11%, respectively, during the quarters and nine months ended September 28, 2018 and September 29, 2017.

Shares Available

As of September 28, 2018 and December 31, 2017, there was an aggregate of 34.0 million and 39.0 million shares of common stock, respectively, available for grant under the Amended and Restated SIP and 7.3 million and 8.0 million shares of common stock, respectively, available for issuance under the ESPP.

Stock Options

The number of options outstanding at December 31, 2017 was 1.1 million at a weighted average exercise price of $6.95 per option, of which 0.7 million options were exercised at a weighted average exercise price of $7.02 per option during the nine months ended September 28, 2018. The number of options outstanding at September 28, 2018 was 0.4 million at a weighted average exercise price of $6.83 per option. All outstanding options had exercise prices below $18.43 per share, the closing price of the Company's common stock at September 28, 2018, and will expire at varying times between 2018 and 2021.

Restricted Stock Units

RSUs generally vest over three years with service-based requirements or performance-based requirements or a combination of service-based and performance-based requirements and are payable in shares of the Company's common stock upon vesting. A summary of the RSU transactions for the nine months ended September 28, 2018 is as follows (in millions, except per share data):



	Number of Shares		Weighted-Average Grant Date Fair Value Per Share
Non-vested RSUs at December 31, 2017	9.8		$	12.63
Granted	3.0		24.30
Achieved	0.7		15.26
Released	(3.9	)	13.02
Forfeited	(0.5	)	15.00
Non-vested RSUs at September 28, 2018	9.1		16.34