In April 2016, our board of directors adopted the 2016 Equity Incentive Plan, which was approved by our stockholders in May 2016 and which was subsequently amended and restated in May 2018 and August 2019 with the approval of our board of directors and our stockholders. Most recently, in June 2024, our board of directors approved a fourth amended and restated equity incentive plan, which was subsequently approved by the Company’s stockholders in August 2024 (the “2016 Fourth Amended Plan”). During the term of the 2016 Fourth Amended Plan, the share reserve will automatically increase on the first trading day in January of each calendar year ending on (and including) January 1, 2034, by an amount equal to 5% of the total number of outstanding shares of common stock and Series C Preferred Stock (determined on an as-converted stock basis) plus all outstanding prefunded warrants to acquire shares of common stock (if any) as of December 31 of the preceding calendar year. On January 1, 2026, pursuant to the terms of the 2016 Fourth Amended Plan, an additional 1,865,256 shares were made available for issuance. As of September 30, 2026, there were 1,084,992 shares available for future issuance under the 2016 Fourth Amended Plan.

In September 2025, our board of directors adopted the 2025 Inducement Award Plan (the “Inducement Plan”). A total of 1,300,000 shares of our common stock were initially reserved for issuance under our Inducement Plan. Grants under the Inducement Plan can be granted to individuals who satisfy the standards for inducement grants under Nasdaq Listing Rule 5635(c)(4), including individuals who were not previously an employee or director of the Company or are following a bona fide period of non-employment, in each case as an inducement material to such individual’s agreement to enter into employment with the Company. As of September 30, 2026, there were 515,400 shares available for future issuance under the Inducement Plan.

Option grants expire after ten years. Employee options typically vest over four years. Employees typically receive a new hire option grant, as well as an annual grant in the first or second quarter of each year. Options granted to directors typically vest immediately or over periods of one or three years. Non-employee directors may elect to receive stock options in lieu of board compensation, which vest immediately. For stock options granted to employees and non-employee directors, the estimated grant date fair market value of the Company’s stock-based awards is amortized ratably over the individuals’ service periods, which is the period in which the awards vest.

Stock-based compensation expense includes expense related to stock options, restricted stock units, performance stock units and employee purchase plan shares. The amount of stock-based compensation expense recognized for the three and nine months ended September 30, 2026 and 2025 was as follows (in thousands):


	Three Months Ended September 30,				Nine Months Ended September 30,
	2026		2025		2026		2025
Research and development	$	1,791	$	1,189	$	4,714	$	3,606
General and administrative	3,429		1,964		9,386		5,507
Total stock-based compensation	$	5,220	$	3,153	$	14,100	$	9,113

The Company has granted stock options that contain service-based vesting conditions. The compensation cost for these options is recognized on a straight-line basis over the vesting periods. A summary of option activity for the nine months ended September 30, 2026 is as follows:


	Options Outstanding
	Number of shares	Weighted average exercise price per share		Weighted average grant date fair value per share		Weighted average remaining contractual term (in years)	Aggregate Intrinsic Value(1) (in millions)
Balance at December 31, 2025	4,591,257	$	13.20	$	10.46	8.5	$	39.9
Granted	1,876,546	$	17.06	$	14.48
Exercised	(1,067,702)	$	9.32	$	7.92		$	9.6
Cancelled	(29,280)	$	9.27	$	7.76		$	0.2
Expired	(346)	$	2,190.95	$	1,394.10
Balance at September 30, 2026	5,370,475	$	15.20	$	12.30	8.7	$	20.7
Exercisable at September 30, 2026	1,165,693	$	22.76	$	16.55	8.1	$	7.6

(1) The aggregate intrinsic value of stock options is calculated as the difference between the exercise price of the stock options and the fair value of the Company’s common stock for those stock options that had exercise prices lower than the fair value of the Company’s common stock.

There were 1,280,083 options that vested during the nine months ended September 30, 2026 with a weighted average exercise price of $8.47 per share. The total grant date fair value of shares which vested during the nine months ended September 30, 2026 and 2025 was $9.1 million and $7.0 million, respectively.

The Company recognized stock-based compensation expense of $4.1 million and $11.4 million related to stock options with service-based vesting conditions for the three and nine months ended September 30, 2026, respectively. The Company recognized stock-based compensation expense of $2.4 million and $7.0 million related to stock options with service-based vesting conditions for the three and nine months ended September 30, 2025, respectively. At September 30, 2026, there was $41.0 million of total unrecognized compensation cost related to unvested service-based vesting condition awards. The unrecognized compensation cost is expected to be recognized over a weighted-average period of 2.8 years.

The Company has granted restricted stock units (“RSUs”) that contain service-based vesting conditions. The Company measures the fair value of the RSUs using the stock price on the date of grant. The compensation cost for RSUs is recognized on a straight-line basis over the vesting period. A summary of RSU activity for the nine months ended September 30, 2026 is as follows:

The RSUs, which were granted on August 13, 2024 under the 2016 Fourth Amended Plan, vest annually over a three-year period, beginning on March 28, 2025. Accordingly, the second tranche of 190,194 RSUs vested on March 28, 2026, of which 56,105 were withheld on behalf of employees to satisfy RSU statutory tax withholdings obligations. The Company recognized stock-based compensation expense of $0.5 million and $1.5 million related to RSUs for the three and nine months ended September 30, 2026, respectively. The Company recognized stock-based compensation of $0.6 million and $1.9 million related to RSUs for the three and nine months ended September 30, 2025, respectively. At September 30, 2026, there was $0.9 million of total unrecognized compensation cost related to RSUs. The unrecognized compensation cost is expected to be recognized over a weighted-average period of 0.5 years.

A performance stock unit (“PSU”) represents one equivalent share of our common stock to be issued after achievement of the performance goals specified in the grant. The Company estimates the fair value of our PSUs as of the grant date based upon the expected likelihood of achievement of the performance goals specified in the grant and the closing market price of our common stock on the date of grant. The Company recognizes stock-based compensation expense over the requisite service period, if it is probable that the performance goal will be achieved.

In August 2025, the Company granted PSUs to executives under the 2016 Fourth Amended Plan with a grant date fair value of $8.90 per unit (the “PSU Awards”). The PSU Awards included 492,500 shares available to vest assuming 100% achievement of the performance metric (the “PSU Target”). The performance metric for the PSUs was based on the timing of data release and efficacy of the Company’s Phase 2 LOTUS trial. The PSUs will vest on the third anniversary of the grant date.

In the second quarter of 2026, the Compensation Committee certified 60% achievement of PSU Target, resulting in 295,500 shares available to vest. This constituted a modification of the original performance condition and the Company measured the fair value of the 295,500 shares using the closing stock price of its common stock on the modification date of $16.60. The Company recognized stock-based compensation expense of $0.5 million and $0.8 million related to the PSUs for the three and nine months ended September 30, 2026, respectively. There was no stock-based compensation expense related to stock options with performance-based vesting conditions in the three and nine months ended September 30, 2025. At September 30, 2026, there was $4.1 million of total unrecognized compensation cost related to the PSUs expected to be recognized over a weighted-average period of 1.9 years.

On April 5, 2016, the Company’s board of directors approved the 2016 Employee Stock Purchase Plan, which was approved by the Company’s stockholders and became effective on May 18, 2016 (the “Initial ESPP”). In June 2024, our board of directors approved an amended and restated employee stock purchase plan, which was subsequently approved by the Company’s stockholders in August 2024 (the “ESPP”). On April 2, 2026, the Company’s board of directors approved the second amended and restated employee stock purchase plan (the “A&R 2016 ESPP”), which was subsequently approved by the Company’s stockholders and became effective on June 2, 2026.

Under the A&R 2016 ESPP, eligible employees can purchase common stock through accumulated payroll deductions at such times as are established by the administrator. The A&R 2016 ESPP is administered by the compensation committee of the Company’s board of directors. Under the A&R 2016 ESPP, eligible employees may purchase stock at 85% of the lower of the fair market value of a share of the Company’s common stock (i) on the first day of an offering period or (ii) on the purchase date. Eligible employees may contribute up to 15% of their earnings during the offering period. The Company’s board of directors may establish a maximum number of shares of the Company’s common stock that may be purchased by any participant, or all participants in the aggregate, during each offering period. Under the A&R 2016 ESPP, a participant may not accrue rights to purchase more than $25,000 of the fair market value of the Company’s common stock for each calendar year in which such right is outstanding.

The Company initially reserved and authorized up to 174 shares of common stock for issuance under the Initial ESPP. Pursuant to the A&R 2016 ESPP, on January 1 of each calendar year, the aggregate number of shares that may be issued under the A&R 2016 ESPP automatically increases by either a number equal the lesser of (i) 4,000,000 shares or (ii) 1% of the Company’s outstanding shares of common stock and Series C Preferred Stock (determined on an as-converted basis) plus all outstanding prefunded warrants to acquire shares of common stock (if any), as of December 31 of the preceding calendar year. On January 1, 2026, the number of shares available for issuance under the A&R 2016 ESPP increased by 373,051 shares pursuant to the evergreen provisions of the ESPP. As of September 30, 2026, 860,787 shares remained available for issuance under the A&R 2016 ESPP.

In accordance with the guidance in ASC 718-50, Employee Share Purchase Plans, the ability to purchase shares of the Company’s common stock at the lower of the offering date price or the purchase date price represents an option and, therefore, the A&R 2016 ESPP is a compensatory plan under this guidance. Accordingly, stock-based compensation expense is determined based on the option’s grant-date fair value and is recognized over the requisite service period of the option. The Company recognized stock-based compensation expense of $0.1 million and $0.4 million related to employee stock purchase plans for the three and nine months ended September 30, 2026, respectively. The Company recognized stock-based compensation expense of $0.1 million and $0.2 million related to employee stock purchase plans for the three and nine months ended September 30, 2025, respectively.