13. Net Loss per Common Share

The Company calculates loss per share using the two-class method, which is an earnings allocation formula that determines earnings per share for Common Stock and participating securities, if any, according to dividends declared and non-forfeitable participation rights in undistributed earnings. Under this method, all earnings (distributed and undistributed) are allocated to Common Stock and participating securities, if any, based on their respective rights to receive dividends. Holders of restricted Common Stock were entitled to all cash dividends, when and if declared, and such dividends are non-forfeitable. The participating securities do not have a contractual obligation to share in any losses of the Company. As a result, net losses are not allocated to the participating securities for any periods presented.

Basic net loss per share is calculated by dividing the net loss by the weighted-average number of shares of Common Stock outstanding during the period, without consideration for Common Stock equivalents. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of Common Stock and Common Stock equivalents outstanding for the period.

Included in Common Stock issued and outstanding as of March 31, 2020 and 2019 were 14,307,564 and 12,622,076 shares of unvested restricted stock, which is excluded from the weighted average Common Stock outstanding for the quarter ended March 31, 2020 since its effect would be dilutive.

The following table sets forth the computation of earnings per share attributable to common stockholders for the quarter ended March 31, 2019 (amounts in thousands except share and per share data):

The Company’s common stock equivalents, including unvested restricted stock, options, and warrants have been excluded from the computation of diluted loss per share for the three months ended March 31, 2020 as the effect would be to reduce the loss per share. Therefore, the weighted average common stock outstanding used to calculate both basic and diluted income loss per share is the same for the quarter ended March 31, 2020.

The following shares of potentially dilutive securities have been excluded from the computation of diluted weighted average shares outstanding, as the effect of including such securities would be anti-dilutive for the three months ended March 31, 2020: