Basic earnings per share is computed by dividing net earnings attributable to common stockholders by the weighted average number of common shares outstanding during the reportable period. Diluted earnings per share is computed by adjusting basic earnings per share for the effect of all potential common shares unless they are anti-dilutive. For purpose of this calculation, potentially dilutive securities are determined by applying the treasury stock method to the assumed exercise of in-the-money stock options and the assumed vesting of outstanding restricted stock awards (RSAs) and release of deferred restricted stock units (RSUs). Potentially dilutive securities related to convertible senior notes are determined using the if-converted method.

The Company's vested deferred RSUs have non-forfeitable rights to dividends prior to release and are considered participating securities. Accordingly, they are included in the computation of basic and diluted earnings per share, pursuant to the two-class method. Under the two-class method, distributed and undistributed earnings allocated to participating securities are excluded from net earnings attributable to common stockholders for purposes of calculating basic and diluted earnings per share. However, net losses are not allocated to participating securities since they are not contractually obligated to share in the losses of the Company.