2. Basic and Diluted Net Loss per Common Share

Basic net loss per share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period, without consideration for common stock equivalents. Diluted net loss per share is calculated by dividing the net loss by the weighted-average number of common share equivalents outstanding for the period determined using the treasury-stock method. Dilutive common stock equivalents are primarily comprised of warrants for the purchase of common stock, Series B Convertible Preferred stock and stock options. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding because their effect would have been anti-dilutive due to the Company reporting a net loss. The Company had potentially dilutive securities, shares of common stock, totaling approximately 21.2 million and 1.5 million as of June 30, 2018 and 2017, respectively.