Earnings per Share

12 Months Ended

Dec. 31, 2019

Earnings Per Share [Abstract]

Earnings per share

Earnings per Share

Basic earnings per share are computed using the weighted average number of shares outstanding and diluted earnings per share are computed using the weighted average number of shares and dilutive share equivalents (consisting of non-qualified stock options, restricted stock units and employee stock purchase plan contributions) outstanding during the periods using the treasury stock method.

The following is a reconciliation of the shares used to compute basic and diluted earnings per share (in millions):

	Year Ended December 31,
	2019	2018	2017
Weighted average number of common shares outstanding used to compute basic earnings per share	52.8	52.3	52.5
Dilutive effect of stock-based awards	0.6	0.8	0.7
Number of shares used to compute diluted earnings per share	53.4	53.1	53.2

There were no significant share equivalents outstanding as of December 31, 2019, 2018 and 2017 that were anti-dilutive when applying the treasury stock method.