
	2020		2019		2018
Stock awards	$	19,435	$	14,265	$	8,930
Stock options	2,378		2,392		2,482
Total stock-based compensation expense(1)	21,813		16,657		11,412
Income tax benefit	5,126		3,998		2,750
Total stock-based compensation expense, net of tax	$	16,687	$	12,659	$	8,662

(1) Changes in annual stock-based compensation expense reflects the cumulative impact of the change in the expected achievements of certain performance targets.

A summary of our stock option activity was as follows (in thousands, except per share amounts and years):


	Stock Options	Weighted- Average Exercise Price per Share		Weighted- Average Remaining Contractual Term (years)	Aggregate Intrinsic Value (1)
Outstanding at December 28, 2019	1,068	$	26.87	6.0	$	24,274
Granted	184	36.11
Exercised	(420)	22.87
Canceled/Forfeited	(19)	38.78
Outstanding at January 2, 2021	813	$	30.74	6.5	$	41,568
Exercisable at January 2, 2021	520	$	26.27	5.3	$	28,913
Vested and expected to vest at January 2, 2021	790	$	30.53	6.4	$	40,553

(1) Aggregate intrinsic value includes only those options where the current share price is equal to or greater than the share price on the date of grant.

Other information pertaining to options was as follows (in thousands, except per share amounts):


	2020		2019		2018
Weighted-average grant date fair value of stock options granted	$	15.10	$	18.97	$	13.96
Total intrinsic value (at exercise) of stock options exercised	$	14,357	$	9,636	$	3,459

Cash received from the exercise of stock options for the fiscal year ended January 2, 2021 was $9.6 million. Our tax benefit related to the exercise of stock options for the fiscal year ended January 2, 2021 was $3.5 million.

At January 2, 2021, there was $2.9 million of total stock option compensation expense related to non-vested stock options not yet recognized, which is expected to be recognized over a weighted-average period of 1.8 years.

The assumptions used to calculate the fair value of options granted using the Black-Scholes-Merton option-pricing model were as follows:


Valuation Assumptions	2020		2019		2018
Expected dividend yield	0.0	%	0.0	%	0.0	%
Expected volatility	46	%	43	%	43	%
Risk-free interest rate	0.7	%	2.2	%	2.7	%
Expected term (years)	5.4		5.4		5.0


	Time- Based Stock Awards	Weighted-Average Grant Date Fair Value		Performance- Based Stock Awards	Weighted-Average Grant Date Fair Value
Outstanding at December 28, 2019	330	$	38.09	592	$	33.30
Granted	309	30.80		291	32.28
Vested	(297)	29.55		(326)	23.66
Canceled/Forfeited	(40)	37.08		(37)	25.91
Outstanding at January 2, 2021	302	$	38.96	520	$	38.52

At January 2, 2021, there was $6.8 million of unrecognized compensation expense related to non-vested time-based stock awards, which is expected to be recognized over a weighted-average period of 1.7 years, and $13.5 million of unrecognized compensation expense related to non-vested performance-based and market-based stock awards, which is expected to be recognized over a weighted-average period of 1.8 years.

During 2018, 5,027 performance-based stock awards with a market condition were granted and had a weighted-average grant date fair value of $35.97 per award. There were no performance-based stock awards with a market condition issued in 2020 or 2019.

The assumptions used to calculate the fair value of the 2018 performance-based stock awards with a market condition, using the Monte Carlo simulation model, were as follows:


Valuation Assumptions	2018
Expected dividend yield	0	%
Expected volatility	43	%
Risk-free interest rate	2.6	%


	2020		2019		2018
Amount repurchased under Board-approved share repurchase program	$	228,111	$	145,900	$	279,101
Amount repurchased in connection with the vesting of employee restricted stock grants	7,040		9,673		3,344
Total amount repurchased (based on trade dates)	$	235,151	$	155,573	$	282,445

As of January 2, 2021, the remaining authorization under our Board-approved share repurchase program was $247 million.

The components of basic and diluted net income per share were as follows (in thousands, except per share amounts):


	2020		2019		2018
Net income	$	139,189	$	81,845	$	69,539
Reconciliation of weighted-average shares outstanding:
Basic weighted-average shares outstanding	27,665		29,472		35,256
Dilutive effect of stock-based awards	763		883		909
Diluted weighted-average shares outstanding	28,428		30,355		36,165
Net income per share – basic	$	5.03	$	2.78	$	1.97
Net income per share – diluted	$	4.90	$	2.70	$	1.92

Additional potential dilutive stock options totaling 0.2 million for each of fiscal years 2020, 2019 and 2018 have been excluded from our diluted net income per share calculations because these securities’ exercise prices were anti-dilutive (e.g., greater than the average market price of our common stock).