8. Stockholders’ Equity

Earnings Per Share

Basic earnings per share (“EPS”) is computed by dividing net income by the weighted average number of shares of common stock outstanding during the year. Diluted EPS is computed considering the dilutive effect of stock options, restricted stock, restricted stock units and performance stock units. The vesting of unvested contingently issuable performance stock units is based on the achievement of certain earnings per share targets and total shareholder return. These shares are considered contingently issuable shares for purposes of calculating diluted earnings per share. These shares are not included in the diluted earnings per share denominator until the performance criteria are met, if it is assumed that the end of the reporting period was the end of the contingency period.

Unvested restricted stock, restricted stock units and performance stock units are included in diluted earnings per share, weighted outstanding until the shares and units vest. Upon vesting, the vested restricted stock, restricted stock units and performance stock units are included in basic earnings per share weighted outstanding from the vesting date.

There were less than 0.1 million anti-dilutive stock options excluded from the calculation of diluted EPS for the three and six months ended June 30, 2018. There were no anti-dilutive stock options for the three and six months ended June 30, 2017.

The following table reconciles the number of shares outstanding with the number of shares used in computing basic and diluted earnings per share for each of the periods presented (in thousands):


	Three Months Ended		Six Months Ended
	June 30,		June 30,
	2018	2017	2018	2017
Common shares outstanding, end of period	37,246	37,288	37,246	37,288
Effect of using weighted average common shares outstanding	(26)	8	(40)	(16)
Shares used in computing earnings per share—basic	37,220	37,296	37,206	37,272
Effect of shares issuable under stock option plans based on the treasury stock method	309	308	341	321
Effect of restricted and contingently issuable shares	76	101	70	121
Shares used in computing earnings per share—diluted	37,605	37,705	37,617	37,714

Share Repurchase Program

On March 29, 2007, our Board of Directors (the “Board”) approved a stock repurchase program to acquire up to 1.0 million shares of our outstanding common stock. Subsequently, the Board has from time to time increased the number of shares that may be acquired under the program and approved extensions of the program. Since the inception of the repurchase program, the Board has approved 8.1 million shares to be repurchased. As of June 30, 2018, we have repurchased a cumulative total of 7.8 million shares at an average price of $14.34 per share under the repurchase program.

The share repurchases will be made from time to time at our discretion in the open market or privately negotiated transactions as permitted by securities laws and other legal requirements, and subject to market conditions and other factors. The Board may modify, suspend, extend or terminate the program at any time. During the six months ended June 30, 2018, we repurchased 0.2 million shares for approximately $6.8 million at an average price of $41.19 per share.