Net Loss Per Share

12 Months Ended

Dec. 31, 2021

3.	Net Loss Per Share

Basic net loss per share is calculated by dividing net loss by the weighted-average number of common stock outstanding during the period without consideration for common stock equivalents. In 2019, preferred stock with characteristics of common stock was also included in the determination of the weighted average. Diluted net loss per share is computed by dividing net loss by the weighted-average number of common stock equivalents outstanding for the period determined using the treasury-stock method. For purposes of this calculation, stock options and warrants for common stock are considered to be common stock equivalents and are only included in the calculation of diluted net loss per share when their effect is dilutive.

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

	As of December 31,
	2021		2020		2019
Series A warrants for common stock		7,790,879		7,802,241		7,802,241
Series B warrants for common stock		2,524,732		2,574,727		2,574,727
Options to purchase common stock		4,937,189		4,146,928		326,023
Warrants for common stock		727,122		727,122		1,839
Total potential dilutive shares		15,979,922		15,251,018		10,704,830

Also excluded from the calculation of diluted net loss per share are 4,824,075 shares of common stock and pre-funded warrants to purchase up to 925,925 common stock issued subsequent to December 31, 2021 (see Note 11).