Basic net (loss) income per common share is computed by dividing net (loss) income by the weighted average number of common shares outstanding for the period. Diluted net (loss) income per share is computed by dividing net (loss) income by the weighted average number of common shares outstanding during the period after giving effect to all dilutive potential common shares that were outstanding during the period. Dilutive potential common shares consist of the incremental common shares issuable upon the exercise of stock options, stock appreciation rights and common stock purchase warrants as determined under the treasury stock method.

The following table provides a reconciliation of the net (loss) income per basic and diluted common share outstanding:

For the nine months ended June 30, 2021, approximately 819,000 potentially dilutive instruments were excluded from the computation of net income per diluted weighted average common share outstanding because their effect would have been antidilutive. Due to our net loss for the three months ended June 30, 2021 and three and nine months ended June 30, 2020, all potentially dilutive instruments were excluded because their inclusion would have been anti-dilutive. See Notes 9 and 10 for a discussion of our potentially dilutive instruments.