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 June 30,				Six Months Ended June 30,
	2018		2017		2018		2017
Weighted average shares outstanding:
Basic weighted average shares outstanding		115,548		117,149		115,595		116,881
Add: Dilutive effect of stock options		—		—		—		—

Diluted weighted average shares outstanding		115,548		117,149		115,595		116,881

The diluted loss per share computation excludes 7.9 million and 10.1 million options to purchase shares, contingently issuable shares, and restricted share awards during the three months ended June 30, 2018 and 2017, respectively, as their effect would be anti-dilutive. The diluted loss per share computation excludes 8.3 million and 10.3 million options to purchase shares, contingently issuable shares, and restricted share awards during the six months ended June 30, 2018 and 2017, respectively, as their effect would be anti-dilutive.

Common stock outstanding as of June 30, 2018 and December 31, 2017, was 115,765,255 and 117,096,731, respectively.