The Board adopted the 2017 Stock Incentive Plan (the "2017 Plan") in February 2017, and the stockholders approved the 2017 Plan in March 2017. The 2017 Plan was most recently amended in March 2020.

As of March 31, 2026, there was an aggregate of 396,795 shares of common stock issuable upon the exercise of outstanding options under the 2017 Plan. Any options or awards outstanding under the 2017 Plan remain outstanding and effective.

In April 2020, the 2020 Equity Incentive Plan (the "2020 Plan") became effective, and, as a result, no further awards will be made under the 2017 Plan. The 2020 Plan provides for the grant of stock options qualifying as incentive stock options, to employees and for the grant of nonstatutory stock options, restricted stock awards, RSU awards, stock appreciation rights, performance stock awards and other forms of stock compensation to employees, consultants and directors. The 2020 Plan also provides for the grant of performance cash awards to employees, consultants and directors. Any previously granted awards under the 2017 Plan will remain outstanding in accordance with their respective terms.

Under the 2020 Plan, there is an annual increase on January 1 of each year from January 1, 2021 continuing through January 1, 2030, by 4.0% of the total number of shares of common stock outstanding on December 31 of the preceding calendar year, or a lesser number of shares as may be determined by the Board. On January 1, 2026, the Company increased the number of shares available for future grant under the 2020 Plan by 781,748 shares. The awards granted under the 2020 Plan typically vest over a two- to four-year period and have a 10-year contractual term.

As of March 31, 2026, there was an aggregate of 4,139,737 shares of common stock issuable upon the exercise of outstanding options and 714,228 shares of common stock issuable upon the vesting of the outstanding RSU awards under the 2020 Plan. Additionally, there were an aggregate of 3,106,467 shares reserved for future issuance under the 2020 Plan, including shares forfeited from the 2017 Plan.


	Number of Units	Weighted Average Grant-Date Fair Value
Outstanding RSU awards as of December 31, 2025	716,850	$	12.37
Granted	176,455	15.62
Vested	(173,827)	11.24
Forfeited	(5,250)	14.82
Outstanding RSU awards as of March 31, 2026	714,228	$	13.43

The summary of RSU award activity includes 90,500 performance-based awards granted during the year ended December 31, 2025. As of March 31, 2026, there has been no expense recognized for the performance-based awards, for which the performance criteria was not deemed probable as of March 31, 2026. As of March 31, 2026, there was approximately $8.7 million of unrecognized stock-based compensation expense related to RSU awards that is expected to vest, including $1.4 million unrecognized stock-based compensation expense related to performance-based awards. These costs are expected to be recognized over a weighted-average remaining vesting period of approximately 2.18 years.

The aggregate fair value of RSU awards that vested during the three months ended March 31, 2026 and 2025 was $2.9 million and zero, respectively.


	NUMBER OF OPTIONS	WEIGHTED-AVERAGE EXERCISE PRICE
Outstanding as of December 31, 2025	3,901,706	$	38.52
Granted	824,938	15.47
Exercised	(15,304)	0.48
Cancelled or Forfeited	(65,125)	61.64
Expired	(109,683)	$	39.41
Outstanding as of March 31, 2026	4,536,532	$	34.10

Options exercisable as of March 31, 2026	3,129,682	$	35.55

The weighted-average grant date fair value price per share of options granted during the three months ended March 31, 2026 was $11.19. There were no options granted during the three months ended March 31, 2025. As of March 31, 2026, there was $26.9 million of unrecognized stock-based compensation expense related to unvested service-based stock options and $0.3 million of unrecognized stock-based compensation expense related to performance-based and market-based stock options. The unrecognized stock-based compensation expense is estimated to be recognized over a period of 2.62 years.

The summary of option activity includes 125,000 performance-based stock options, 62,500 of which were cancelled during the three months ended March 31, 2026. The options include performance-based and service-based vesting criteria. During the three months ended March 31, 2026, the Company recognized $0.1 million of stock-based compensation expense related to these performance-based options. As of March 31, 2026, there was $0.3 million of unrecognized stock-based compensation expense related to service-based vesting criteria that the Company expects to recognize.

The summary of option activity also includes 100,000 market-based stock options that were granted during the three months ended March 31, 2026. The Company measured the fair value of the market-based awards on the grant date using a Monte Carlo Simulation, incorporating various option pricing inputs. The weighted-average grant date fair value of the market-based awards is estimated as $10.85 per share and the total compensation expense is $1.1 million. Due to a non-substantive explicit service condition, the total compensation expense was recognized during the three months ended March 31, 2026.

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. The aggregate intrinsic value of the stock options outstanding and stock options exercisable was $4.2 million and $4.2 million as of March 31, 2026, respectively. The aggregate intrinsic value of stock options exercised was $0.2 million and $0.1 million during the three months ended March 31, 2026 and 2025, respectively.

In March 2020, the Board adopted and the Company's stockholders approved the 2020 Employee Stock Purchase Plan ("ESPP"). The ESPP became effective on April 7, 2020. Under the ESPP, eligible employees can purchase shares of the Company's common stock, based on a percentage of their compensation, subject to certain limits. The purchase price per share is equal to the lower of 85% of the fair market value of the Company's common stock on the first trading day of the twenty-four month offering period, or on the applicable purchase date. Each offering under the ESPP consists of two twelve-month purchase periods.

Under the ESPP, there is an annual increase on January 1 of each year from January 1, 2021 continuing through January 1, 2030, by the lesser of (i) 1.0% of the total number of shares of common stock outstanding on December 31 of the preceding calendar year, (ii) 455,852 shares or (iii) a lesser number of shares as may be determined by the Board. On January 1, 2026, the Company increased the number of shares available for future grant under the ESPP by 195,437 shares. If purchase rights

granted under the ESPP terminate without having been exercised, the shares of our common stock not purchased under such purchase rights will again become available for issuance under the ESPP.

As of March 31, 2026, 11,806 shares of common stock were purchased under the ESPP. As of March 31, 2026, there was an aggregate of 1,837,039 shares reserved for future issuance under the ESPP.

Total stock-based compensation expense recorded for employees, directors and non-employees during the three months ended March 31, 2026 and 2025 was as follows (in thousands):


	THREE MONTHS ENDED MARCH 31,
	2026		2025
Research and development	$	2,287	$	5,265
General and administrative	3,912		3,598
Total stock-based compensation expense	$	6,199	$	8,863