In October 2005, our shareholders approved a stock option and incentive plan (the “2005 Plan”) under which 4,800,000 shares of common stock were reserved for the issuance of awards, including incentive stock options and non-qualified stock options, stock appreciation rights, restricted stock, unrestricted stock, restricted stock units, performance shares, performance units (including performance options) and other share-based awards. The 2005 Plan provides that our employees and directors may, at the discretion of the Board of Directors ("Board") or a duly designated compensation committee, be granted certain share-based awards. In the case of option awards granted under the 2005 Plan, the exercise price of each option is determined based on the date of grant and expire no later than 10 years from the date of grant. Awards granted pursuant to the 2005 Plan are subject to the vesting schedule or performance metrics set forth in the agreements pursuant to which they are granted. Upon a change of control of our Company, as such term is defined in the 2005 Plan, awards under the 2005 Plan will fully vest under certain circumstances. The 2005 Plan expired on May 25, 2015. As of June 30, 2021, there were 102,520 outstanding options under the 2005 Plan.

In August 2015, our shareholders approved a stock option and incentive plan (the “2015 Plan”) under which 11,500,000 shares of common stock were reserved for the issuance of awards, including incentive stock options and non-qualified stock options, stock appreciation rights, restricted stock awards and restricted stock unit awards, performance stock awards and other share-based awards. In August 2017, our shareholders approved an amendment to the 2015 Plan, (the “Amended 2015 Plan”), to, among other items, increase the number of shares of common stock reserved for issuance thereunder by 6,000,000, which was further amended in August 2019 as approved by our shareholders, to, among other items, increase the number of shares of common stock reserved for issuance thereunder by an additional 3,575,000. The Amended 2015 Plan provides that our employees and directors may, at the discretion of the Board or a duly designated compensation committee, be granted certain share-based awards. In the case of option awards granted under the Amended 2015 Plan, the exercise price of each option is determined based on the date of grant and expire no later than 10 years from the date of grant. Awards granted pursuant to the Amended 2015 Plan are subject to the vesting schedule or performance metrics set forth in the agreements pursuant to which they are granted. Upon a change of control of our Company, as such term is defined in the Amended 2015 Plan, awards under the Amended 2015 Plan will fully vest under certain circumstances. As of June 30, 2021, there were 2,638,864 outstanding options, 2,172,959 outstanding shares of restricted stock awards, certain outstanding performance stock unit awards as described further below, and 1,592,107 shares available for future grant under the Amended 2015 Plan.

The following table summarizes the stock option transactions during the three months ended June 30, 2021:

				Weighted-		Weighted-
				Average		Average		Aggregate
				Exercise		Remaining		Intrinsic
	Number of			Price		Contractual		Value
	Shares			per Share		Life (years)		(in thousands)
Outstanding, March 31, 2021		2,791,084		$	14.47		3.70	$	10,303
Exercised		(700	)		15.99		0.93	$	—
Forfeited/Canceled		(10,000	)		21.27		5.09
Expired		(39,000	)		17.95
Outstanding, June 30, 2021		2,741,384		$	14.40		3.54	$	6,270
Vested and expected to vest, June 30, 2021		2,688,422		$	14.39		3.52	$	6,165
Exercisable, June 30, 2021		2,421,002		$	14.34		3.41	$	5,636

Share-based compensation expense related to stock options was $709 and $732 for the three months ended June 30, 2021 and 2020, respectively.

Non-vested stock option award activity during the three months ended June 30, 2021 is summarized as follows:

				Weighted-
				Average
				Grant-Date
	Number of			Fair Value
	Shares			per Share
Outstanding, March 31, 2021		459,339		$	5.96
Vested		(128,957	)		6.21
Forfeited/Canceled		(10,000	)		8.74
Outstanding, June 30, 2021		320,382		$	5.78

As of June 30, 2021, $677 of total unrecognized compensation costs related to stock options is expected to be recognized over a weighted-average period of 0.5 years. This amount does not include the cost of new options that may be granted in future periods or any changes in our forfeiture percentage. The total fair value of options vested during the three months ended June 30, 2021 and 2020 was $800 and $1,378, respectively.

Restricted stock awards activity during the three months ended June 30, 2021 is summarized as follows:

				Weighted-
				Average
				Grant-Date
	Number of			Fair Value
	Shares			per Share
Outstanding, March 31, 2021		2,263,569		$	14.58
Granted		548,768			16.59
Vested		(518,519	)		14.92
Canceled		(120,859	)		14.69
Outstanding, June 30, 2021		2,172,959		$	15.00

Share-based compensation expense related to restricted stock awards was $6,458 for the three months ended June 30, 2021 and includes the impact of incremental expense incurred from the accelerated vesting of certain equity awards associated with the departure of our Chief Executive Officer. Share-based compensation expense related to restricted stock awards was $4,039 for the three months ended June 30, 2020.

The weighted-average grant date fair value for the restricted stock awards was estimated using the market price of the common stock on the date of grant. The fair value of the restricted stock awards is amortized on a straight-line basis over the vesting period, which is generally between one to three years.

As of June 30, 2021, $24,148 of total unrecognized compensation costs related to restricted stock awards is expected to be recognized over a weighted-average period of 1.9 years. This amount does not include the cost of new restricted stock awards that may be granted in future periods.

On October 23, 2018, the Compensation Committee of the Board approved 248,140 performance stock unit awards to be granted to certain executives and non-executive members of the executive leadership team, which vest only in the event certain performance goals are achieved and with continuous service through the date the goals are certified. Approximately 34% of the performance stock units are tied to our cumulative 3-year total shareholder return, 33% are tied to our fiscal year 2021 revenue, and 33% are tied to our fiscal year 2021 adjusted earnings per share goals, each as specifically defined in the equity award agreements. The number of shares to be issued may vary between 50% and 200% of the number of performance stock units depending on performance, and no such shares will be issued if threshold performance is not achieved. The weighted-average grant date fair value of the awards was $17.84 per share, which was estimated using a Monte Carlo-based valuation model for the awards based on total shareholder return and using a probability-adjusted achievement rate combined with the market price of the common stock on the date of grant for the awards based on revenue and earnings per share targets. Share-based compensation expense related to the performance stock unit awards was a benefit of $438 for the three months ended June 30, 2021 primarily due to cancellation of awards associated with the departure of our Chief Executive Officer. Share-based compensation expense related to the performance stock unit awards was $114 for the three months ended June 30, 2020.

On December 26, 2019 and January 27, 2020, the Compensation Committee of the Board approved a total of 279,587 performance stock unit awards to be granted to certain executives and non-executive members of the executive leadership team, which vest only in the event certain performance goals are achieved and with continuous service through the date the goals are certified. Approximately 80% of the performance stock units are tied to the Company’s fiscal year 2021 revenue goal and 20% are tied to the Company’s fiscal year 2022 revenue goal. Performance stock unit awards funded for fiscal year 2021 and fiscal year 2022 revenue performance will be modified for cumulative 3-year total shareholder return (“TSR”) on the three-year grant anniversary, which is also the cliff vest date. The number of shares to be issued may vary between 42.5% and 172.5% of the number of performance stock units depending on performance, and no such shares will be issued if threshold performance is not achieved. The weighted-average grant date fair value of the awards was $16.02 per share, which was estimated using a Monte Carlo-based valuation model for the awards based on total shareholder return and using a probability adjusted achievement rate combined with the market price of the common stock on the date of grant for the awards based on revenue targets. Share-based compensation expense related to the performance stock unit awards was a benefit of $457 for the three months ended June 30, 2021 primarily due to cancellation of awards associated with the resignation of our Chief Executive Officer. Share-based compensation expense related to the performance stock unit awards was $281 for the three months ended June 30, 2020.

On October 26, 2020, the Compensation Committee of the Board approved 408,861 performance stock unit awards to be granted to certain executives and non-executive members of the executive leadership team, which vest only in the event certain performance goals are achieved and with continuous service through the date the goals are certified. Approximately 80% of the performance stock units are tied to the Company’s fiscal year 2022 revenue goal and 20% are tied to the Company’s fiscal year 2023 revenue goal. Performance stock unit awards funded for fiscal year 2022 and fiscal year 2023 revenue performance will be modified for cumulative 3-year TSR on the three-year grant date anniversary, which is also the cliff vest date. The number of shares to be issued may vary between 8.5% and 199.5% of the number of target performance stock units depending on performance, and no such shares will be issued if threshold performance is not achieved. The weighted-average grant date fair value of the awards was $16.25 per share, which was estimated using a Monte Carlo-based valuation model for the awards based on total shareholder return and using a probability adjusted achievement rate combined with the market price of the common stock on the date of grant for the awards based on revenue targets. Share-based compensation expense related to the performance stock unit awards was a benefit of $61 for the three months ended June 30, 2021 primarily due to cancellation of awards associated with the resignation of our Chief Executive Officer.

As of June 30, 2021, $5,223 of total estimated unrecognized compensation costs related to performance stock units and awards is expected to be recognized over a weighted-average period of 2.1 years. This amount does not include the cost of new performance stock units and awards that may be granted in future periods.

On August 11, 2014, our shareholders approved an Employee Share Purchase Plan (the “Purchase Plan”) under which 4,000,000 shares of common stock were reserved for future grant. The Purchase Plan allows eligible employees to purchase shares through payroll deductions of up to 15% of total base salary at a price equal to 90% of the lower of the fair market values of the shares as of the beginning or the end of the corresponding offering period. Any shares purchased under the Purchase Plan are subject to a six-month holding period. Employees are limited to purchasing no more than 1,500 shares on any single purchase date and no more than $25 in total fair market value of shares during any one calendar year. As of June 30, 2021, we have issued 791,209 shares under the Purchase Plan and 3,208,791 shares are available for future issuance.

Share-based compensation expense recorded for the employee share purchase plan was $201 and $164 for the three months ended June 30, 2021 and 2020, respectively.