The following table provides a reconciliation of the net income/(loss) amounts and weighted average number of common and common equivalent shares used to determine basic and diluted earnings per share for the three and six months ended October 31, 2019 and 2018 (in thousands, except per share data):

	For the Three Months Ended October 31,
	2019								2018
	Net					Per Share			Net					Per Share
	Income			Shares		Amount			Income			Shares		Amount
Basic earnings	$		1,293		54,912	$		0.02	$		6,665		54,444	$		0.12
Effect of dilutive stock awards		—			512		—			—		663			—
Diluted earnings	$		1,293		55,424	$		0.02	$		6,665		55,107	$		0.12

	For the Six Months Ended October 31,
	2019										2018
	Net						Per Share				Net					Per Share
	Loss				Shares		Amount				Income			Shares		Amount
Basic earnings	$		(815	)		54,847	$		(0.01	)	$		14,310		54,395	$		0.26
Effect of dilutive stock awards		—			—			—				—			652		—
Diluted earnings	$		(815	)		54,847	$		(0.01	)	$		14,310		55,047	$		0.26

For the three months ended October 31, 2019, options to purchase 45,441 shares of common stock were excluded from the computation of diluted earnings per share because the effect would be antidilutive. All of our outstanding stock options and restricted stock units, or RSUs, were included in the computation of diluted earnings per share for the three months ended October 31, 2018. All of our outstanding stock options and RSUs were included in the computation of diluted earnings per share for the three and six months ended October 31, 2019 and 2018.

We have two incentive stock plans: the 2004 Incentive Stock Plan and the 2013 Incentive Stock Plan. New grants under the 2004 Incentive Stock Plan have not been made since the approval of the 2013 Incentive Stock Plan at our September 23, 2013 annual meeting of stockholders. All new grants covering all participants are issued under the 2013 Incentive Stock Plan. Except in specific circumstances, grants vest over a period of three or four years and stock options are exercisable for a period of 10 years from the date of grant. The plan also permits the grant of awards to non-employees, which our board of directors has authorized in the past.

The number of shares and weighted average exercise prices of stock options for the three and six months ended October 31, 2019 and 2018 were as follows:

	For the Six Months Ended October 31,
	2019					2018
				Weighted					Weighted
				Average					Average
	Shares			Exercise Price		Shares			Exercise Price
Options outstanding, beginning of year		267,761		$	6.76		316,160		$	6.69
Exercised during the period		(15,000	)		5.79		(32,899	)		6.52
Options outstanding, end of period		252,761		$	6.82		283,261		$	6.71
Weighted average remaining contractual life	1.97 years					2.74 years
Options exercisable, end of period		252,761		$	6.82		283,261		$	6.71
Weighted average remaining contractual life	1.97 years					2.74 years

The aggregate intrinsic value of outstanding and exercisable stock options as of October 31, 2019 and 2018 was $335,000 and $2.0 million, respectively. The aggregate intrinsic value of stock options exercised in the three and six months ended October 31, 2019 was $100,000. The aggregate intrinsic value of the stock options exercised in the three and six months ended October 31, 2018 was $154,000 and $230,000, respectively. At October 31, 2019, there was no unrecognized compensation expense relating to outstanding stock options.

We have an Employee Stock Purchase Plan, or ESPP, in which each participant is granted an option to purchase our common stock on each subsequent exercise date during the offering period (as such terms are defined in the ESPP) in accordance with the terms of the ESPP.

The total stock-based compensation expense, including stock options, purchases under our ESPP, RSUs, and performance-based RSUs, or PSUs, was $3.0 million and $4.0 million for the six months ended October 31, 2019 and 2018, respectively. Stock-based compensation expense is included in cost of sales, sales and marketing, research and development, and general and administrative expenses.

We grant service-based RSUs to employees and directors. The awards are made at no cost to the recipient. An RSU represents the right to receive one share of our common stock and does not carry voting or dividend rights. Except in specific circumstances, RSU grants to employees vest over a period of four years with one-fourth of the units vesting on each anniversary of the grant date. We amortize the aggregate fair value of our RSU grants to compensation expense over the vesting period.

We grant PSUs to our executive officers and certain management employees who are not executive officers. The PSUs vest, and the fair value of such PSUs will be recognized, over the corresponding three-year performance period.

During the six months ended October 31, 2019, we granted an aggregate of 252,911 service-based RSUs, including 137,271 RSUs to non-executive officer employees and 115,640 RSUs to our directors. Compensation expense related to grants of RSUs and PSUs was $2.7 million for the six months ended October 31, 2019. During the six months ended October 31, 2019, we cancelled 156,725 PSUs as a result of the failure to satisfy the performance metric and 67,454 service-based RSUs as a result of the service condition not being met. In connection with the vesting of RSUs, during the six months ended October 31, 2019, we delivered common stock to our employees and directors, including our executive officers, with a total market value of $1.9 million.

During the six months ended October 31, 2018, we granted an aggregate of 191,085 service-based RSUs, including 141,576 RSUs to non-executive officer employees and 49,509 RSUs to our directors. Compensation expense related to grants of RSUs and PSUs was $3.6 million for the six months ended October 31, 2018. During the six months ended October 31, 2018, we cancelled 112,000 PSUs as a result of the failure to satisfy the performance metric and 16,363 service-based RSUs as a result of the failure to satisfy the service condition. In connection with the vesting of RSUs, during the six months ended October 31, 2018, we delivered common stock to our employees and directors, including our executive officers with a total market value of $2.2 million.

A summary of activity for unvested RSUs and PSUs for the six months ended October 31, 2019 and 2018 is as follows:

	For the Six Months Ended October 31,
	2019					2018
				Weighted					Weighted
	Total # of			Average		Total # of			Average
	Restricted			Grant Date		Restricted			Grant Date
	Stock Units			Fair Value		Stock Units			Fair Value
RSUs and PSUs outstanding, beginning of period		1,631,631		$	15.44		1,442,316		$	17.80
Awarded		252,911			7.54		191,085			12.61
Vested		(236,489	)		17.62		(182,536	)		19.83
Forfeited		(224,179	)		18.04		(128,363	)		15.91
RSUs and PSUs outstanding, end of period		1,423,874		$	13.26		1,322,502		$	16.99

As of October 31, 2019, there was $6.2 million of unrecognized compensation expense related to unvested RSUs and PSUs. This expense is expected to be recognized over a weighted average remaining contractual term of 1.5 years.