5. Net Loss per Share

Basic net loss per share was determined by dividing net loss by the weighted average shares outstanding during the period. Diluted net loss per share was determined by dividing net loss by diluted weighted average shares outstanding. Diluted weighted average shares reflect the dilutive effect, if any, of common stock options based on the treasury stock method.

For all financial statement periods presented, the number of basic and diluted weighted average shares outstanding remained the same as an increase in the number of shares of common stock equivalents for the periods presented would be antidilutive.

For the nine months ended September 30, 2017 and 2016, approximately 0.7 million and 7.4 million weighted average shares, subject to stock options and warrants, respectively, as calculated using the treasury stock method, were excluded from the calculation of diluted weighted average shares outstanding as their effect was antidilutive.