Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2020

Accounting Policies [Abstract]

Weighted Average Shares and Share Equivalents Used to Calculate Basic and Diluted Earnings Per Share

The following weighted average shares and share equivalents were used to calculate basic and diluted earnings per share for the years ended December 31, 2020, 2019 and 2018:

	Year Ended December 31,
	2020	2019	2018
Weighted average number of shares outstanding used to    calculate basic EPS	3,692	3,641	3,631
Dilutive securities:
Stock options and restricted share units	225	332	461
Weighted average number of shares and share equivalents outstanding used to calculate diluted EPS	3,917	3,973	4,092

Summary of Antidilutive Securities Excluded from Computation of Earnings Per Share

The following stock options issued under equity incentive plans were outstanding during the years ended December 31, 2020, 2019 and 2018, but were not included in the computation of diluted earnings per share because the effect would have been anti-dilutive.

	Year Ended December 31,
	2020	2019	2018
Anti-dilutive securities	31	319	370