Basic net loss per share is calculated by dividing the net loss by the weighted average number of shares of common stock outstanding and fully vested restricted stock units. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common share equivalents outstanding for the period determined using the treasury-stock method. Common stock equivalents are comprised of unvested restricted stock units, warrants to purchase common stock and options outstanding under the stock option plans. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding since the effects of potentially dilutive securities are antidilutive due to the net loss position.

The following outstanding common stock equivalents were excluded from the computation of diluted net loss per share for the periods presented because including them would have been antidilutive: