10. Stock-Based Compensation

Stock Option and Incentive Plans

In April 2016, the Company adopted the Amended and Restated 2015 Stock Option and Incentive Plan (the “2015 Plan”). The 2015 Plan provides for the grant of incentive stock options, non-qualified stock options, stock appreciation rights, restricted stock awards (“RSAs”), restricted stock units (“RSUs”) and other stock-based awards. Recipients of incentive stock options and non-qualified stock options are eligible to purchase shares of the Company’s common stock at an exercise price equal to the fair value of such stock on the grant date.

In June 2025, the Company adopted the 2025 Equity Incentive Plan (the “2025 Plan”). The 2025 Plan provides for the grant of incentive stock options, non-qualified stock options, stock appreciation rights, RSAs, RSUs, unrestricted stock awards, cash-based awards and dividend equivalent rights. Recipients of incentive stock options and non-qualified stock options are eligible to purchase shares of the Company’s common stock at an exercise price equal to the fair value of such stock on the grant date. The Company no longer grants any awards under the 2015 Plan. The shares of common stock underlying any awards that are forfeited, cancelled, or otherwise terminated, other than by exercise, under the 2025 Plan and the 2015 Plan will be added back to the shares of common stock available for issuance under the 2025 Plan. As of March 31, 2026, there were 9,724,526 shares available for future issuance under the 2025 Plan.

In June 2024, the Company adopted the 2024 Inducement Plan, which was amended in December 2025 (as amended, the “Inducement Plan”). The Inducement Plan provides for the grant of non-qualified stock options, stock appreciation rights, RSAs, RSUs, unrestricted stock awards and dividend equivalent rights to individuals who are not employed by the Company. Recipients of non-qualified stock options are eligible to purchase shares of the Company’s common stock at an exercise price equal to the fair value of such stock on the grant date. At March 31, 2026, 1,553,938 shares were available for issuance under the Inducement Plan.

Restricted Stock Units

The weighted-average grant date fair value of all RSUs granted during the three months ended March 31, 2026 and 2025 was $14.70 and $10.67, respectively. The total fair value of RSUs vested (measured on the date of vesting) for the three months ended March 31, 2026 and 2025 was $13.9 million and $17.5 million, respectively.

As of March 31, 2026, there was $72.2 million of unrecognized stock-based compensation expense related to all RSUs that are expected to vest. These costs are expected to be recognized over a weighted average remaining vesting period of 1.87 years.

Restricted Stock Units - Service Awards

The Company awards RSUs with a service condition to new employees upon hire, non-employee directors upon appointment, and to existing employees and non-employee directors as part of their annual grant. RSUs with a service condition granted to new and existing employees, and to non-employee directors upon appointment, generally vest as to one-third on the first anniversary of the original vesting date, with the balance vesting annually over the remaining two years. RSUs granted to non-employee directors with a service condition as part of their annual grant generally vest on the first anniversary of the original vesting date.

In the three months ended March 31, 2026, the Company granted 2,563,521 RSUs with a service condition to new and existing employees, which have the potential to vest over a period of approximately three years. The weighted average grant date fair value of these RSUs was $13.73.

Unvested restricted stock units as of March 31, 2026 in the table above includes 5,203,446 RSUs that are service-based.

Restricted Stock Units - Market Awards

The Company awards market-based RSUs to senior executives which have the potential to vest after a period of three years, with a vesting start date of January 1 in the year of grant, and the number of shares to be delivered will depend on the Company’s Total Shareholder Return (“TSR”), a market condition, over that period relative to a defined group of biotechnology companies. The number of market-based RSUs granted in the three months ended March 31, 2026 and 2025 was 255,328 and 223,600, respectively. The grant date fair value for the market-based RSUs, calculated using a Monte Carlo valuation model, was $24.43 and $15.76, respectively. The following assumptions were used to determine the grant date fair value for the three months ended March 31, 2026 and 2025, respectively: risk free interest rate: 3.40% and 3.99%; expected volatility: 80.9% and 67.6%. The expected term for all grants was approximately 3.0 years; the expected dividend yield was 0.0%.

Unvested restricted stock units as of March 31, 2026 in the table above includes 713,805 RSUs that are market-based.

Restricted Stock Units - Performance-Based Awards with TSR Multiplier

In 2024, performance-based RSUs (“PSUs”) with a relative TSR modifier were granted to senior executives. The number of PSUs with a relative TSR modifier granted in the year ended December 31, 2024 was 486,617. These PSUs, to the extent earned, shall vest on January 1, 2027, and the number of shares to be delivered will be determined based upon the achievement of certain performance goals, which can range from 0% to 200%. Following the determination of the achievement of performance criteria, the amount of shares awarded will be subject to adjustment based on the application of a TSR modifier, which can range from 75% to 125%. The grant date fair value for these PSUs, calculated using a Monte Carlo valuation model, was $36.16. The following assumptions were used to determine the grant date fair value: risk free interest rate: 4.28%; expected volatility: 77.2%; expected term: approximately 3.0 years; expected dividend yield: 0.0%. The Company recognizes compensation expense ratably over the required service period based on its estimate of the number of shares that will vest based upon the probability of achieving the performance goals.

There were no PSUs with a relative TSR modifier granted in the three months ended March 31, 2026 and 2025. Unvested restricted stock units as of March 31, 2026 in the table above includes 352,662 PSUs with a TSR multiplier.

Stock Options

The weighted average grant date fair value of options, estimated as of the grant date using the Black-Scholes option pricing model, was $10.01 and $6.92 per option for those options granted during the three months ended March 31, 2026 and 2025, respectively. Weighted average assumptions used to apply this pricing model were as follows:

Risk-free Interest Rate. The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant with maturities approximately equal to the option’s expected term.

Expected Term. The expected term represents the period that stock option awards are expected to be outstanding. For option grants that are considered to be “plain vanilla,” the Company determines the expected term using the simplified method. The simplified method deems the term to be the average of the time-to-vesting and the contractual life of the options. The Company uses the simplified method because it concluded that its stock option exercise history does not provide a reasonable basis upon which to estimate expected term.

Expected Volatility. Expected volatility is estimated based on actual movements in the Company’s stock price over the most recent historical periods, over the expected term of their stock option grants.

Expected Dividend Yield. The Company has not paid cash dividends and has no intention to pay cash dividends in the future.

Stock options generally vest as to one-third on the first anniversary of the original vesting date, with the balance vesting monthly over the remaining two years, unless they contain other specific vesting provisions. The maximum term of stock options granted under the 2015 Plan, the 2025 Plan and the Inducement Plan is ten years.

There were no options exercised during the three months ended March 31, 2026 or 2025.

As of March 31, 2026, there was $10.5 million of unrecognized compensation cost related to stock options that have not yet vested, which are expected to be recognized over a weighted average remaining vesting period of 1.5 years.

Employee Stock Purchase Plan

In May 2016, the Company adopted the 2016 Employee Stock Purchase Plan (the “2016 Plan”). The 2016 Plan allows eligible employees to purchase shares of the Company’s common stock on the last day of each predetermined six-month offering period at 85% of the lower of the fair market value per share at the beginning or end of the applicable offering period. The 2016 Plan provides for six-month offering periods beginning in January and July of each year.

As of March 31, 2026, there were 1,524,879 shares available for future issuance under the 2016 Plan. The number of shares reserved for issuance under the 2016 Plan was increased on January 1, 2026 by 500,000 shares of common stock. During the three months ended March 31, 2026 and 2025 the Company did not issue any shares of common stock under the 2016 Plan.