Earnings (Loss) Per Share

Basic earnings (loss) per common share is calculated by dividing net income (loss) by the weighted average number of common shares outstanding for the period. Diluted earnings (loss) per common share is calculated by dividing net income (loss) by the weighted average number of common shares outstanding combined with dilutive common share equivalents outstanding, if the effect is dilutive.

Potentially dilutive securities were excluded from the calculation of diluted loss per share for the three and nine months ended September 30, 2018 and 2017, since including them would have an anti-dilutive effect on loss per share due to the net loss incurred during the periods. Securities convertible into shares of common stock that were not considered in the diluted loss per share calculations were 0.9 million restricted stock units for the three and nine months ended September 30, 2018, and 12,100 stock options and 1.2 million restricted stock units for the three and nine months ended September 30, 2017.

A reconciliation of the number of shares used for the basic and diluted earnings (loss) per common share computations is as follows (in thousands):



	Three months ended September 30,		Nine months ended September 30,
	2018	2017	2018	2017
Weighted average common shares outstanding - Basic	58,319	57,602	57,820	57,709
Assumed conversions:
Incremental common shares from stock options	—	—	—	—
Incremental common shares from restricted stock units	—	—	—	—
Weighted average common shares outstanding - Diluted	58,319	57,602	57,820	57,709