Warrants

12 Months Ended

Dec. 31, 2022

Warrants

Warrants

11. Warrants

The following common stock warrants were outstanding at December 31, 2022:

	Number of
	Common	Per Share
	Stock	Exercise
	Warrants	Price		Issuance Date	Expiration Date
Issued with common units in the 2018 Unit Offering	3,300		2.7568	October 2, 2018	October 2, 2023
Issued with common units in the 2018 Registered Direct Offering	92,300		5.40	October 10, 2018	October 10, 2023
Issued with common units in the 2019 Registered Direct Offering	50,000		3.21	March 12, 2019	March 12, 2024
Issued with common units in the 2020 Public Offering (see Note 10)	869,566		0.0001	July 16, 2020	—
Total	1,015,166

The following common stock warrants were outstanding at December 31, 2021:

	Number of
	Common	Per Share
	Stock	Exercise
	Warrants	Price		Issuance Date	Expiration Date
Replacement warrants	155	$	483.00	March 3, 2012	March 3, 2022
Issued with common units in the 2018 Unit Offering	3,300		2.7568	October 2, 2018	October 2, 2023
Issued with common units in the 2018 Registered Direct Offering	92,300		5.40	October 10, 2018	October 10, 2023
Issued with common units in the 2019 Registered Direct Offering	50,000		3.21	March 12, 2019	March 12, 2024
Issued with common units in the 2020 Public Offering (see Note 10)	1,630,436		0.0001	July 16, 2020	—
Issued in exchange for retirement of common stock per the Exchange Agreement (see Note 10)	1,000,000		0.0001	February 25, 2021	—
Total	2,776,191

The following is a description of the common stock warrants issued prior to January 1, 2020:

2019 Registered Direct Offering

On March 12, 2019, the Company issued a combined total of 4,361,370 common units and pre-funded units to certain institutional investors in a registered direct offering (the “Registered Direct Offering”). Each common unit in the Registered Direct Offering was sold at a price of $3.21 and consisted of one share of common stock and 0.70 of a warrant to purchase one share of common stock at an exercise price of $3.21. Each warrant sold in the Registered Direct Offering was exercisable immediately and expired five years from the date of issuance. All of the pre-funded warrants were exercised during 2019. The warrants issued in the Registered Direct Offering were recognized as equity classified

freestanding financial instruments. As of December 31, 2022, there were 50,000 unexercised warrants issued under the 2019 Registered Direct Offering.

2018 Unit Offering

On October 2, 2018, the Company issued a combined total of 2,400,000 common units and pre-funded units in a public offering (the “2018 Unit Offering”). Each common unit in the 2018 Unit Offering was sold at a public offering price of $5.00 and consisted of one share of common stock and a warrant to purchase one share of common stock at an exercise price of $6.00. Each warrant sold in the 2018 Unit Offering was exercisable immediately and expired five years from the date of issuance. All of the pre-funded warrants were exercised prior to December 31, 2018.

The warrants issued in the 2018 Unit Offering are each subject to anti-dilution protection. Accordingly, to the extent the Company was to issue additional common stock or securities convertible into common stock at an issuance price lower than exercise price of the warrants, the exercise price of the warrants would be adjusted to the lower of (i) the issuance price or (ii) the lowest volume weighted-average price of the Company’s common stock on the five trading days following the announcement of the new offering. The 2018 Registered Direct Offering triggered a down round adjustment to the exercise price of the warrants issued in the 2018 Unit Offering from $6.00 to $4.1798. In addition, the 2019 Registered Direct Offering triggered a down round adjustment to the exercise price of the warrants issued in the 2018 Unit Offering from $4.1798 to $2.7568. As of December 31, 2022, there were 3,300 unexercised warrants issued under the 2018 Unit Offering.

2018 Registered Direct Offering

On October 10, 2018, the Company issued a combined total of 4,629,630 common units and pre-funded units to certain institutional investors in a registered direct offering (the “2018 Registered Direct Offering”). Each common unit in the 2018 Registered Direct Offering was sold at a price of $5.40 and consisted of one share of common stock and a warrant to purchase one share of common stock at an exercise price of $5.40. Each warrant sold in the 2018 Registered Direct Offering was exercisable immediately and expired five years from the date of issuance. All of the pre-funded warrants were exercised prior to December 31, 2018. As of December 31, 2022, there were 92,300 unexercised warrants issued under the 2018 Registered Direct Offering.

A summary of warrant activity is as follows:

				Weighted-Average
			Weighted	Remaining
	Number of		Average	Contractual Term
	Warrants		Exercise Price	(Years)
Warrants outstanding, December 31, 2021	2,776,191
Expired	(155)
Exercises (see Note 10)	(1,760,870)
Warrants outstanding, December 31, 2022	1,015,166	$	0.66	0.9