8. Loss Per Share

Basic loss per share is computed on the basis of weighted average outstanding common shares. Diluted loss per share is computed on the basis of basic weighted average outstanding common shares adjusted for the dilutive effect of stock options and other outstanding dilutive securities.

The following table reconciles the average share amounts used to compute both basic and diluted loss per share (in thousands):


	Three Months Ended March 31,
	2018		2017
Weighted average shares outstanding:
Basic weighted average shares outstanding		115,642		116,610
Add: Dilutive effect of stock options		—		—

Diluted weighted average shares outstanding		115,642		116,610

The diluted loss per share computation excludes 8.6 million and 10.5 million options to purchase shares, contingently issuable shares, and restricted share awards during the three months ended March 31, 2018 and 2017, respectively, as their effect would be anti-dilutive.

Common stock outstanding as of March 31, 2018 and December 31, 2017 was 116,394,285 and 117,096,731, respectively.