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 September 30, 2025, there was an aggregate of 412,099 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, 2025, the Company increased the number of shares available for future grant under the 2020 Plan by 1,622,188 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 September 30, 2025, there was an aggregate of 4,114,663 shares of common stock issuable upon the exercise of outstanding options and 721,700 shares of common stock issuable upon the vesting of the outstanding RSU awards under the 2020 Plan. Additionally, there were an aggregate of 2,554,450 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, 2024	—	$	—
Granted	1,121,175	11.56
Vested	—	—
Forfeited	(399,475)	10.56
Outstanding RSU awards as of September 30, 2025	721,700	$	12.11

The summary of RSU award activity includes performance-based awards granted during the nine months ended September 30, 2025. As of September 30, 2025, there has been no expense recognized for the performance-based awards. As of September 30, 2025, there was approximately $7.2 million of unrecognized stock-based compensation expense related to RSU awards that is expected to vest, including $1.4 million of unrecognized stock-based compensation expense related to performance-based awards for which the performance criteria is currently not deemed probable. These costs are expected to be recognized over a weighted-average remaining vesting period of approximately 1.79 years.


	NUMBER OF OPTIONS	WEIGHTED-AVERAGE EXERCISE PRICE
Outstanding as of December 31, 2024	5,384,760	$	42.19
Granted	84,000	14.82
Exercised	(65,653)	0.35
Cancelled or Forfeited	(766,443)	54.60
Expired	(109,902)	$	47.75
Outstanding as of September 30, 2025	4,526,762	$	40.05

Options exercisable as of September 30, 2025	3,541,878	$	36.94

The summary of option activity includes performance-based stock options granted during 2024. As of September 30, 2025, there has been no expense recognized for the performance-based stock options. The weighted-average grant date fair value price per share of options granted during the nine months ended September 30, 2025 and 2024 was $10.36 and $40.11, respectively. As of September 30, 2025, there was $32.9 million of unrecognized stock-based compensation expense related to unvested stock options, including $4.9 million of unrecognized stock-based compensation expense related to unvested performance-based stock options for which the performance criteria is currently not deemed probable. The unrecognized stock-based compensation expense is estimated to be recognized over a period of 1.64 years.

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 $6.5 million and $6.4 million as of September 30, 2025, respectively. The aggregate intrinsic value of stock options exercised was $0.7 million and $8.5 million during the nine months ended September 30, 2025 and 2024, 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) or a lesser number of shares as may be determined by the Board. On January 1, 2025, the Company increased the number of shares available for future grant under the ESPP by 405,547 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 September 30, 2025, 11,806 shares of common stock were purchased under the ESPP. As of September 30, 2025, there was an aggregate of 1,641,602 shares reserved for future issuance under the ESPP.

Total stock-based compensation expense recorded for employees, directors and non-employees during the three and nine months ended September 30, 2025 and 2024 was as follows (in thousands):


	THREE MONTHS ENDED SEPTEMBER 30,				NINE MONTHS ENDED SEPTEMBER 30,
	2025		2024		2025		2024
Research and development	$	992	$	4,699	$	11,230	$	13,225
General and administrative	2,994		4,118		10,161		12,447
Total stock-based compensation expense	$	3,986	$	8,817	$	21,391	$	25,672