
			Shares
			Available for
			Grant
Balance, March 25, 2017			4,692
Shares added			—
Granted			(1,755)
Forfeited			128
Balance, March 31, 2018			3,065
Shares added			2,509
Granted			(2,371)
Forfeited			120
Balance, March 30, 2019			3,323
Shares added			248
Granted			(1,686)
Forfeited			210
Balance, March 28, 2020			2,095

The following table summarizes the effects of stock-based compensation on cost of goods sold, research and development, sales, general and administrative, pre-tax income, and net income after taxes for shares granted under the Plan (in thousands, except per share amounts):


	Fiscal Year
	2020		2019		2018
Cost of sales	$	908	$	877	$	1,474
Research and development	33,859		29,115		26,137
Sales, general and administrative	18,990		19,697		21,130
Effect on pre-tax income	53,757		49,689		48,741
Income Tax Benefit	(9,336)		(5,748)		(5,953)
Total stock-based compensation expense (net of taxes)	44,421		43,941		42,788
Stock-based compensation effects on basic earnings per share	$	0.76	$	0.73	$	0.67
Stock-based compensation effects on diluted earnings per share	0.73		0.71		0.65

The total stock-based compensation expense included in the table above and which is attributable to restricted stock units and market stock units was $50.0 million, $45.5 million, $44.2 million, for fiscal years 2020, 2019, and 2018, respectively. Stock-based compensation expense is presented within operating activities in the Consolidated Statement of Cash Flows.

As of March 28, 2020, there was $97.1 million of compensation costs related to non-vested stock options, restricted stock units, and market stock units granted under the Company’s equity incentive plans not yet recognized in the Company’s financial statements. The unrecognized compensation cost is expected to be recognized over a weighted average period of 1.31 years for stock options, 1.61 years for restricted stock units, and 1.55 years for market stock units.

In addition to the income tax benefit of stock-based compensation expense shown in the table above, the Company recognized excess tax benefits of $4.9 million, $0.9 million and $11.7 million in fiscal years 2020, 2019, and 2018 respectively.

We estimate the fair value of each stock option on the date of grant using the Black-Scholes option-pricing model using a dividend yield of zero and the following additional assumptions:


	March 28, 2020	March 30, 2019	March 31, 2018
Expected stock price volatility	37.17% - 41.61%	38.00% - 38.14%	37.36	%
Risk-free interest rate	1.54% - 2.29%	2.57% - 2.94%	1.67	%
Expected term (in years)	3.81 - 4.55	3.12 - 3.73	3.03

The Black-Scholes valuation calculation requires us to estimate key assumptions such as stock price volatility, expected term, risk-free interest rate and dividend yield. The expected stock price volatility is based upon implied volatility from traded options on our stock in the marketplace. The expected term of options granted is derived from an analysis of historical exercises and remaining contractual life of stock options, and represents the period of time that options granted are expected to be outstanding after becoming vested. The risk-free interest rate reflects the yield on zero-coupon U.S. Treasury securities for a period that is commensurate with the expected term assumption. Finally, we have never paid cash dividends, do not currently intend to pay cash dividends, and thus have assumed a zero percent dividend yield.

Using the Black-Scholes option valuation model, the weighted average estimated fair values of employee stock options granted in fiscal years 2020, 2019, and 2018, were $29.25, $16.27, and $19.87, respectively.

During fiscal years 2020, 2019, and 2018, we received a net $18.6 million, $1.6 million, and $4.4 million, respectively, from the exercise of 0.8 million, 0.1 million, and 0.2 million, respectively, stock options granted under the Company’s Stock Plan.

The total intrinsic value of stock options exercised during fiscal year 2020, 2019, and 2018, was $34.0 million, $2.6 million, and $9.8 million, respectively. Intrinsic value represents the difference between the market value of the Company’s common stock at the time of exercise and the strike price of the stock option.


	Outstanding Options
	Number	Weighted Average Exercise Price
Balance, March 25, 2017	1,758	$	27.25
Options granted	216	55.72
Options exercised	(234)	18.84
Options forfeited	—	—
Options expired	—	—
Balance, March 31, 2018	1,740	$	31.91
Options granted	280	40.41
Options exercised	(108)	15.03
Options forfeited	(38)	49.62
Options expired	(9)	55.01
Balance, March 30, 2019	1,865	$	33.68
Options granted	169	66.93
Options exercised	(780)	23.90
Options forfeited	(27)	50.75
Options expired	(11)	55.03
Balance, March 28, 2020	1,216	$	44.01

Additional information with regards to outstanding options that are vesting, expected to vest, or exercisable as of March 28, 2020 is as follows (in thousands, except years and per share amounts):


	Number of Options	Weighted Average Exercise price		Weighted Average Remaining Contractual Term (years)	Aggregate Intrinsic Value
Vested and expected to vest	1,205	$	43.90	6.49	$	22,733
Exercisable	781	$	38.41	5.31	$	18,360

In accordance with U.S. GAAP, stock options outstanding that are expected to vest are presented net of estimated future option forfeitures, which are estimated as compensation costs are recognized. Options with a fair value of $4.7 million, $4.1 million, and $3.8 million, became vested during fiscal years 2020, 2019, and 2018, respectively.


	Options Outstanding							Options Exercisable
		Weighted Average Remaining Contractual Life	Weighted Average Exercise		Number	Weighted Average
Range of Exercise Prices	Number	(years)	Price		Exercisable	Exercise Price
$14.58 - $31.25	324	4.51	$	26.98	324	$	26.98
$33.38 - $38.99	240	4.76	38.11		188	38.11
$41.49 - $42.64	183	8.63	41.56		54	41.49
$54.65 - $54.65	154	6.60	54.65		127	54.65
$55.72 - $55.72	157	7.60	55.72		88	55.72
$68.56 - $68.56	158	9.61	68.56		—	—
	1,216	6.51	$	44.01	781	$	38.41

Commencing in fiscal year 2011, the Company began granting restricted stock units (“RSUs”) to select employees. These awards are valued as of the grant date and amortized over the requisite vesting period. Generally, RSUs vest 100 percent on the first to third anniversary of the grant date depending on the vesting specifications. A summary of the activity for RSUs in fiscal year 2020, 2019, and 2018 is presented below (in thousands, except year and per share amounts):


	Shares	Weighted Average Fair Value
March 25, 2017	2,995	$	34.91
Granted	936	55.79
Vested	(1,077)	24.79
Forfeited	(85)	41.09
March 31, 2018	2,769	$	45.70
Granted	1,416	40.57
Vested	(1,176)	33.65
Forfeited	(175)	48.15
March 30, 2019	2,834	$	47.99
Granted	1,014	66.76
Vested	(897)	51.20
Forfeited	(271)	50.82
March 28, 2020	2,680	$	53.74

The aggregate intrinsic value of RSUs outstanding as of March 28, 2020 was $165.9 million. Additional information with regards to outstanding RSUs that are expected to vest as of March 28, 2020, is as follows (in thousands, except year and per share amounts):

RSUs outstanding that are expected to vest are presented net of estimated future forfeitures, which are estimated as compensation costs are recognized. RSUs with a fair value of $45.9 million and $39.6 million became vested during fiscal years 2020 and 2019, respectively. The majority of RSUs that vested in 2020 and 2019 were net settled such that the Company withheld a portion of the shares to satisfy tax withholding requirements. In fiscal years 2020 and 2019, the vesting of RSUs reduced the authorized and unissued share balance by approximately 0.9 million and 1.2 million, respectively. Total shares withheld and subsequently retired out of the Plan were approximately 0.3 million and 0.3 million, and total payments for the employees’ tax obligations to taxing authorities were $18.3 million and $13.1 million for fiscal years 2020 and 2019, respectively.

In fiscal year 2015, the Company began granting market stock units (“MSUs”) to select employees. MSUs vest based upon the relative total shareholder return (“TSR”) of the Company as compared to that of the Philadelphia Semiconductor Index (“the Index”). The requisite service period for these MSUs is also the vesting period, which is three years. The fair value of each MSU granted was determined on the date of grant using the Monte Carlo simulation, which calculates the present value of the potential outcomes of future stock prices of the Company and the Index over the requisite service period. The fair value is based on the risk-free rate of return, the volatilities of the stock price of the Company and the Index, the correlation of the stock price of the Company with the Index, and the dividend yield.


	Fiscal Years Ended
	March 28, 2020	March 30, 2019
Expected stock price volatility	37.17% - 41.61%	38.00% - 38.14%
Risk-free interest rate	1.59% - 2.28%	2.62% - 3.01%
Expected term (in years)	3.00	3.00

Using the Monte Carlo simulation, the weighted average estimated fair value of the MSUs granted in fiscal year 2020 was $95.89. A summary of the activity for MSUs in fiscal year 2020, 2019, and 2018 is presented below (in thousands, except year and per share amounts):


	Shares	Weighted Average Fair Value
March 25, 2017	180	$	47.30
Granted	89	47.26
Vested	(70)	22.00
Forfeited	—	—
March 31, 2018	199	$	56.16
Granted	68	53.13
Vested	—	—
Forfeited	(101)	43.41
March 30, 2019	166	$	62.77
Granted	45	95.89
Vested	—	—
Forfeited	(58)	73.25
March 28, 2020	153	$	68.71

The aggregate intrinsic value of MSUs outstanding as of March 28, 2020 was $9.5 million. Additional information with regard to outstanding MSUs that are expected to vest as of March 28, 2020 is as follows (in thousands, except year and per share amounts):