NET INCOME (LOSS) PER SHARE

The Company has a share-based compensation plan under which employees may be granted share-based awards including shares of restricted stock and restricted stock units ("RSUs"). Non-forfeitable dividends are paid on unvested shares of restricted stock. No dividends are accrued or paid on unvested RSUs. As such, shares of restricted stock are considered participating securities under the two-class method of calculating earnings per share. The two-class method of calculating earnings per share did not have a material impact on the Company’s earnings per share calculation as of December 31, 2017, 2016 and 2015.

The following table sets forth the computation of basic and diluted shares (in thousands):



	Years Ended December 31,
	2017		2016		2015
Weighted average common shares outstanding	49,253		49,203		51,841
Unvested common shares subject to repurchase	(2	)	(16	)	(39	)
Total common shares-basic	49,251		49,187		51,802
Effect of dilutive securities:
Options	—		357		343
Restricted stock awards and units	—		646		441
Total common shares-diluted	49,251		50,190		52,586

Basic net income (loss) per share is computed using the weighted average number of common shares outstanding during the period, excluding any unvested restricted stock awards that are subject to repurchase. Diluted net income (loss) per share is computed using the treasury stock method to calculate the weighted average number of common shares and, if dilutive, potential common shares outstanding during the period. Potential dilutive common shares include unvested restricted stock awards and units and incremental common shares issuable upon the exercise of stock options, less shares from assumed proceeds. The assumed proceeds calculation includes actual proceeds to be received from the employee upon exercise and the average unrecognized stock compensation cost during the period.

For the year ended December 31, 2017, there was no difference in the weighted average number of common shares used for the calculation of basic and diluted loss per share as the effect of all potentially dilutive shares outstanding was anti-dilutive. A total of 3.0 million shares subject to stock options and restricted stock awards and units were excluded from the computation of diluted net loss per share because including them would have been anti-dilutive.

For the years ended December 31, 2016 and 2015 in the calculation of net income per share, 0.7 million and 0.1 million shares, respectively, subject to stock options and restricted stock awards and units were excluded from the computation of diluted net income per share as they were anti-dilutive.