On May 12, 2021, the Company’s shareholders approved the Company’s Amended and Restated 2008 Incentive Compensation Plan (the “Amended and Restated 2008 Incentive Plan”). The amendments, among other things, increased the number of shares of common stock reserved for delivery under the Amended and Restated 2008 Incentive Plan from 27,775,000 shares to 34,975,000 shares, as well as extended the expiration date to 10 years from the effective date of approval. The Amended and Restated 2008 Incentive Plan provides for grants of stock options, stock appreciation rights, restricted stock, deferred stock, and other stock-related awards and performance awards that may be settled in cash, stock or other property.

Under the Amended and Restated 2008 Incentive Plan, options to purchase shares of common stock may be granted at a price not less than the fair market value of the shares on the date of grant. The options must be exercised within 10 years from the date of grant and generally become exercisable on a pro rata basis over a three-year period from the date of grant. The Company issues new shares of its common stock upon exercise of its stock options. Restricted stock awards generally vest over periods of three years upon the fulfillment of specified service-based conditions and in certain instances performance-based conditions. Deferred stock awards generally vest upon the satisfaction of specified performance-based conditions and service-based conditions. The Company recognizes compensation expense related to its restricted stock and deferred stock awards ratably over the corresponding vesting periods. During the year ended December 31, 2021, the Company granted 0.7 million shares of restricted stock to its employees and non-employee directors under the Amended and Restated 2008 Incentive Plan. At December 31, 2021, the Company had 10.9 million shares available for future grants and awards under the Amended and Restated 2008 Incentive Plan.

On May 12, 2021, the Company’s shareholders approved the Company’s Amended and Restated 1996 Non-Qualified Employee Stock Purchase Plan (the “ESPP”) to increase the number of shares issuable under the ESPP to 9.9 million shares. Under the ESPP, employees are permitted to purchase the Company's common stock at 85% of market value on January 1st, April 1st, July 1st and October 1st of each year. Under the Company’s 2015 Non-Qualified Stock Purchase Plan (the “SPP”), certain eligible non-employee service providers are permitted to purchase the Company’s common stock at 90% of market value on January 1st, April 1st, July 1st and October 1st of each year.

The Company recognizes stock-based compensation expense for the discount received by participating employees and non-employee service providers. During the year ended December 31, 2021, approximately 0.2 million shares were issued under the ESPP. At December 31, 2021, the Company had approximately 2.8 million shares reserved for issuance under the ESPP. At December 31, 2021, the Company had approximately 61,000 shares reserved for issuance under the SPP. No shares have been issued under the SPP in 2021.

The Company recognized $19.0 million, $21.1 million and $33.4 million of stock-based compensation expense related to its stock incentive plans, the ESPP and the SPP during the years ended December 31, 2021, 2020 and 2019, respectively.

The activity related to the Company's restricted stock awards and the corresponding weighted average grant-date fair values for the year ended December 31, 2021 are as follows:


	Number of Shares			Weighted Average Fair Value
Non-vested shares at January 1, 2021		1,211,117		$	30.97
Awarded		736,477		$	25.17
Forfeited		(55,378	)	$	28.20
Vested		(748,410	)	$	33.55
Non-vested shares at December 31, 2021		1,143,806		$	25.68

The aggregate fair value of the restricted stock that vested during the years ended December 31, 2021, 2020 and 2019 was $25.1 million, $59.3 million and $31.5 million, respectively.

The weighted average grant-date fair value of restricted stock awards that were granted during the years ended December 31, 2021, 2020 and 2019 was $25.17, $23.54 and $33.28, respectively.

At December 31, 2021, the total stock-based compensation cost related to non-vested restricted stock remaining to be recognized as compensation expense over a weighted-average period of 1.5 years was $11.3 million.

The activity and certain other information related to the Company’s outstanding stock option awards for the year ended December 31, 2021 are as follows:


	Number of Stock Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in millions)
Outstanding at January 1, 2021		999,291		$	17.30
Awarded		—
Exercised		(95,000	)	$	17.65
Expired		(16,560	)	$	36.25				—
Outstanding at December 31, 2021		887,731		$	16.91		1.88	$	9.1
Exercisable at December 31, 2021		887,731		$	16.91		1.88	$	9.1

The aggregate intrinsic value of stock options exercised during the years ended December 31, 2021 and 2019 were $1.7 million and $0.6 million, respectively.

The cash proceeds received from the exercise of stock options for the years ended December 31, 2021 and 2019 were $1.7 million and $0.1 million, respectively.