7. COMMON STOCK

Common Stock Issued, Net of Issuance Costs

December 2020 Purchase Agreement with Lincoln Park Capital Fund, LLC

On December 4, 2020, the Company entered into a Purchase Agreement with Lincoln Park (“the “December 2020 PA”) to place up to $100.0 million in the aggregate of the Company's common stock on an ongoing basis when required by the Company over a term of 36 months. The Company controls the timing and amount of any sales to Lincoln Park, and Lincoln Park is obligated to make purchases in accordance with the December 2020 PA. Any common stock that is sold to Lincoln Park will occur at a purchase price that is based on an agreed upon fixed discount to the Company's prevailing market prices at the time of each sale and with no upper limits to the price Lincoln Park may pay to purchase common stock. The agreement may be terminated by the Company at any time, in its sole discretion, without any additional cost or penalty.

The December 2020 PA specifically provides that the Company may not issue or sell any shares of its common stock under the agreement if such issuance or sale would breach any applicable rules of the NYSE American Stock Exchange (“NYSE American”). In particular, NYSE American General Rule 713(a) provides that the Company may not issue or sell more than 19.99% of the number of shares of the Company’s common stock that were outstanding immediately prior to the execution of the December 2020 PA unless (i) shareholder approval is obtained or (ii) the average price of all applicable sales of common stock to Lincoln Park under the December 2020 PA, equals of exceeds $6.15. The Company has scheduled its Annual Shareholders Meeting for May 21, 2021 and has included a proposal in its Proxy Statement which seeks shareholder approval for the issuance of more than 19.99% of the shares of the Company’s common stock outstanding on December 4, 2020.

Lincoln Park has no right to require the Company to sell any shares of common stock to Lincoln Park, but Lincoln Park is obligated to make purchases as the Company directs, subject to certain conditions. In all instances, the Company may not sell shares of its common stock to Lincoln Park under the December 2020 PA if it would result in Lincoln Park beneficially owning more than 9.99% of its common stock.

During the three months ended March 31, 2021, the Company sold 3.8 million shares of common stock for net proceeds of $24.9 million pursuant to the December 2020 PA with Lincoln Park. These shares were sold pursuant to a Form S‑3 registration statement filed pursuant to Rule 424(b)(3) and declared effective by the Securities and Exchange Commission on December 4, 2020. As of March 31, 2021, the Company has sold approximately 19.9% of the outstanding shares of common stock as of the date of the December 2020 PA.

ATM Offering Agreement with Cantor

On April 14, 2017, the Company entered into a Controlled Equity OfferingSM Sales Agreement (the “ATM Offering Agreement”) with Cantor acting as sales agent. Under the ATM Offering Agreement, the Company may from time to time sell shares of its common stock in “at-the-market” offerings. The Company pays Cantor a commission of up to 2.5% of the gross proceeds from the sale of any shares pursuant to the ATM Offering Agreement.

During the three months ended March 31, 2021, the Company sold 9.3 million shares of common stock for net proceeds of $47.3 million pursuant to the ATM Offering Agreement with Cantor. These shares were sold pursuant to a prospectus supplement filed on December 4, 2020 pursuant to Rule 424(b)(5) as a takedown off the Company’s shelf registration statement which had been declared effective by the Securities and Exchange Commission on December 1, 2020. As of March 31, 2021, the Company has no shares of common stock registered for sale under the ATM Offering Agreement.

Warrants

The following table summarizes warrants outstanding and changes for the three-month periods ending March 31, 2021 and 2020:

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	March 31, 2021	March 31, 2020

	Number of	Number of
	Warrants	Warrants
Warrants outstanding at beginning of period	—	197,622
Issued	—	—
Expired	—	—
Warrants outstanding at end of period	—	197,622

On October 6, 2020, a warrant holder of 182,515 warrants provided notice of exercise. The warrant holder elected the cashless exercise method to convert the warrants to shares of common stock. Based on the cashless exercise formula, the Company issued the warrant holder 118,799 shares of common stock.