Basic net (loss) income per common share is calculated by dividing net (loss) income by the weighted average number of common shares outstanding during the period. Diluted net income per common share is computed by dividing net (loss) income by the weighted average number of common and common equivalent shares outstanding during the period. The Company’s potentially dilutive common shares are those that result from dilutive common stock options and non-vested stock relating to restricted stock awards and restricted stock units. However, these items have been excluded from the calculation of diluted net loss per share for the three months ended December 31, 2020 as their effect was antidilutive as a result of the net loss incurred for that period. Therefore, diluted weighted average number of shares outstanding and diluted net loss per share were the same as basic weighted average number of shares outstanding and net loss per share for the three months ended December 31, 2020.

The following table sets forth the calculation of diluted weighted average shares outstanding:

	Three Months Ended
	December 31,
(In thousands)	2020		2019
Basic weighted average shares outstanding		13,668		13,469
Dilutive effect of outstanding stock options, non-vested restricted stock, and non-vested restricted stock units		—		300
Diluted weighted average shares outstanding		13,668		13,769

The calculation of weighted average diluted shares outstanding excludes outstanding stock options associated with the right to purchase 0.1 million shares of common stock for the three months ended December 31, 2019, as their inclusion would have had an antidilutive effect on diluted net income per share for the period.