On February 12, 2021, the Company completed a common stock offering pursuant to which certain investors purchased 4,081,633 shares of common stock at a price of $49.00 per share. Net proceeds of the offering were approximately $189.8 million after deducting offering expenses.

In March 2020, the Company established an at-the-market offering program (“ATM”) to sell, from time to time, shares of Company common stock having an aggregate offering price of up to $100 million in transactions pursuant to a shelf registration statement that was declared effective by the U.S. Securities and Exchange Commission (the “SEC”) on May 5, 2020. The Company is obligated to pay a commission of 3.0% of the gross proceeds from the sale of shares of common stock in the offering. The Company is not obligated to sell any shares in the offering.

There were no common stock sales under the ATM during the three and nine months ended September 30, 2022 and 2021.

In August 2018, the Company issued warrants to purchase up to an aggregate of 9.1 million shares of its common stock in conjunction with an offering of its common stock.

The Company did not receive any proceeds from exercise of common stock warrants during the three and nine months ended September 30, 2022.

The Company did not receive any proceeds from exercise of common stock warrants during the three months ended September 30, 2021. During the nine months ended September 30, 2021, the Company received proceeds of $0.7 million from the exercise of 0.6 million shares pursuant to warrants.

During the nine months ended September 30, 2022, stock options and unvested Performance Awards outstanding under the Company’s stock option plans changed as follows:


	Stock Options	Performance Awards
Outstanding as of December 31, 2021	2,663,727	138,055
Options granted	4,000	—
Options exercised	(194,264)	—
Options forfeited/canceled	(22,139)	(130,913)
Outstanding as of September 30, 2022	2,451,324	7,142

The weighted average exercise price of options outstanding at September 30, 2022 was $11.03. As outstanding options vest over the current remaining vesting period of 1.7 years, the Company expects to recognize stock-based

compensation expense of $4.9 million. If and when outstanding Performance Awards vest, the Company will recognize stock-based compensation expense of $0.1 million over the implicit service period.

During the three months ended September 30, 2022, there were 18,740 stock options exercised with cash proceeds to the Company totaling $136,000.

During the nine months ended September 30, 2022, there were 194,264 stock options exercised. Of the stock options exercised, 94,399 stock options were net settled in satisfaction of the exercise price, with no cash proceeds received. Cash proceeds to the Company for options not net settled totaled $466,000 during the nine months ended September 30, 2022.

During the nine months ended September 30, 2022, a total of 57,143 shares of restricted stock awards expired as performance criteria related to these Performance Awards were not attained. These shares of restricted stock were returned to the 2008 Equity Incentive Plan, which expired in December 2017, and thus were retired.

During the three and nine months ended September 30, 2022 and 2021, the Company’s stock-based compensation expense was as follows (in thousands):



	Three months ended				Nine months ended
	September 30,				September 30,
	2022		2021		2022		2021
Research and development	$	399	$	452	$	1,234	$	867

General and administrative		71		120		216		370

Total stock-based compensation expense	$	470	$	572	$	1,450	$	1,237

The Company’s Board of Directors (the “Board”) or a designated committee of the Board is responsible for administration of the Company’s 2018 Omnibus Incentive Plan, as amended (the “2018 Plan”) and determines the terms and conditions of each option granted, consistent with the terms of the 2018 Plan. The Company’s employees, directors, and consultants are eligible to receive awards under the 2018 Plan, including grants of stock options and Performance Awards. Share-based awards generally expire 10 years from the date of grant. The 2018 Plan, as amended on May 5, 2022, provides for issuance of up to 5,000,000 shares of common stock, par value $0.001 per share, subject to adjustment as provided in the 2018 Plan.