Basic net income (loss) per common share is calculated by dividing net income (loss) by the weighted average number of common shares outstanding during the period. Diluted net income (loss) per common share is computed by dividing net income (loss) by the weighted average number of common and dilutive common equivalent shares outstanding during the period. The Company’s potentially dilutive common shares are those that result from dilutive common stock options, non-vested stock relating to restricted stock awards, restricted stock units, deferred stock units and performance shares. Options to purchase shares of common stock as well as unvested restricted stock and performance stock units are considered to be potentially dilutive common shares. However, these shares have been excluded from the calculation of diluted net loss per share as their effect is antidilutive for the three and nine months ended June 30, 2018, as a result of the net losses incurred for those periods. 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 and nine months ended June 30, 2018.

The calculation of weighted average diluted shares outstanding excludes outstanding stock options associated with the right to purchase 0.2 million and 0.1 million shares of common stock for the three and nine months ended June 30, 2019, respectively, as their inclusion would have had an antidilutive effect on diluted net income per share for those periods.

The following table sets forth the denominator for the computation of basic and diluted net income (loss) per share (in thousands):

	Three Months Ended					Nine Months Ended
	June 30,					June 30,
	2019		2018			2019		2018
Net income (loss) available to common shareholders	$	1,466	$	(2,682	)	$	4,038	$	(2,704	)
Basic weighted average shares outstanding		13,394		13,203			13,384		13,117
Dilutive effect of outstanding stock options, non-vested restricted stock, restricted stock units, deferred stock units and performance shares		332		—			392		—
Diluted weighted average shares outstanding		13,726		13,203			13,776		13,117

The Company’s Board of Directors has authorized the repurchase of up to $25.3 million of the Company’s outstanding common stock. This authorization does not have an expiration date.