Stockholders' Equity (Tables)

3 Months Ended

Mar. 31, 2022

Equity [Abstract]

Summary of Shares of Common Stock Reserved

The Company has reserved for future issuances the following shares of common stock as of March 31, 2022 and December 31, 2021:

	March 31, 2022		December 31, 2021
Stock options and restricted stock units		11,691,089		8,372,313
Warrants		10,687,912		10,687,912
Common stock issuable upon conversion of outstanding debt		1,219,512		2,439,024
Employee stock purchase plan		306,527		306,527
Total		23,905,040		21,805,776

Warrants

At March 31, 2022 and December 31, 2021, the Company had 10,687,912 warrants outstanding for the purchase of shares of common stock at a weighted average exercise price of $1.26. 10,678,872 warrants with an exercise price of $1.25 expire on July 16, 2026. 9,040 warrants with an exercise price of $11.06 expire on May 1, 2026. Additionally, in a concurrent private placement in connection with the registered direct offering completed in May 2022, the Company issued 22,438,575 warrants with an exercise price of $0.1694 and 1,256,561warrants with an exercise price of $0.20 that expire on May 3, 2027.