Stock-Based Compensation

The following presents stock-based compensation expense in the Company’s Consolidated Statements of Operations:



	Three Months Ended				Six Months Ended
	March 30, 2019		March 31, 2018		March 30, 2019		March 31, 2018
Cost of revenues	$	2.0	$	2.5	$	4.0	$	4.7
Research and development	2.7		2.9		5.4		5.4
Selling and marketing	2.7		2.5		5.4		5.4
General and administrative	10.1		11.6		19.8		19.1
Restructuring	—		—		—		1.3
	$	17.5	$	19.5	$	34.6	$	35.9

The Company granted options to purchase 0.9 million and 1.7 million shares of the Company's common stock during the six months ended March 30, 2019 and March 31, 2018, respectively, with weighted-average exercise prices of $41.25 and $40.76, respectively. There were 6.0 million options outstanding at March 30, 2019 with a weighted-average exercise price of $34.47.

The Company uses a binomial model to determine the fair value of its stock options. The weighted-average assumptions utilized to value these stock options are indicated in the following table:



	Three Months Ended						Six Months Ended
	March 30, 2019			March 31, 2018			March 30, 2019			March 31, 2018
Risk-free interest rate	3.0		%	2.1		%	3.0		%	2.1		%
Expected volatility	34.3		%	35.3		%	34.3		%	35.3		%
Expected life (in years)	4.8			4.7			4.8			4.7
Dividend yield	—			—			—			—
Weighted average fair value of options granted	$	15.33		$	12.53		$	13.50		$	12.98

The Company granted 0.9 million and 0.8 million restricted stock units (RSUs) during the six months ended March 30, 2019 and March 31, 2018, respectively, with weighted-average grant date fair values of $41.11 and $40.75 per unit, respectively. In addition, the Company granted 0.1 million and 0.4 million performance stock units (PSUs) during the six months ended March 30, 2019 and March 31, 2018, respectively, to members of its senior management team, which have a weighted-average grant date fair value of $40.97 and $40.86 per unit, respectively. Each recipient of PSUs is eligible to receive between zero and 200% of the target number of shares of the Company’s common stock at the end of three years provided the Company’s defined Return on Invested Capital metrics are achieved. The Company is recognizing compensation expense ratably over the required service period based on its estimate of the number of shares that will vest. If there is a change in the estimate of the number of shares that are probable of vesting, the Company cumulatively adjusts compensation expense in the period that the change in estimate is made. The Company also granted 0.1 million and 0.3 million market based awards (MSUs) to its senior management team during the six months ended March 30, 2019 and March 31, 2018, respectively. Each recipient of MSUs is eligible to receive between zero and 200% of the target number of shares of the Company’s common stock at the end of three years based upon achieving a certain total shareholder return relative to a defined peer group. The MSUs were valued at $55.13 and $49.45 per share using the Monte Carlo simulation model. The Company is recognizing compensation expense for the MSUs ratably over the service period. At March 30, 2019, there was 2.7 million in aggregate RSUs, PSUs and MSUs outstanding.

At March 30, 2019, there was $29.6 million and $82.2 million of unrecognized compensation expense related to stock options and stock units (comprised of RSUs, PSUs and MSUs), respectively, to be recognized over a weighted-average period of 2.7 and 2.1 years, respectively.