Net Loss Per Share	9 Months Ended
Sep. 30, 2019
Earnings Per Share [Abstract]
Net Loss Per Share	3. Net Loss Per 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 computed by dividing the net loss by the weighted average number of common shares and common stock equivalents outstanding for the period determined using the treasury stock method. For purposes of this calculation, stock options, employee stock purchase plan rights, restricted stock units, and warrants are considered to be common stock equivalents but are not included in the calculations of diluted net loss per share for the periods presented as their effect would be anti-dilutive. The Company incurred net losses for all periods presented and there were no reconciling items for potentially dilutive securities. More specifically, at September 30, 2019 and 2018, stock options, employee stock purchase plan rights, restricted stock units, and warrants totaling approximately 20,912,000 shares and 19,775,000 shares, respectively, were excluded from the calculation of diluted net loss per share as their effect would have been anti-dilutive.

Net Loss Per Share

9 Months Ended

Sep. 30, 2019

3. Net Loss Per 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 computed by dividing the net loss by the weighted average number of common shares and common stock equivalents outstanding for the period determined using the treasury stock method. For purposes of this calculation, stock options, employee stock purchase plan rights, restricted stock units, and warrants are considered to be common stock equivalents but are not included in the calculations of diluted net loss per share for the periods presented as their effect would be anti-dilutive. The Company incurred net losses for all periods presented and there were no reconciling items for potentially dilutive securities. More specifically, at September 30, 2019 and 2018, stock options, employee stock purchase plan rights, restricted stock units, and warrants totaling approximately 20,912,000 shares and 19,775,000 shares, respectively, were excluded from the calculation of diluted net loss per share as their effect would have been anti-dilutive.