v3.26.1
Stockholders' Equity (Tables)
 6 Months Ended
Jun. 30, 2026
Summary of Common Stock Reserved for Future Issuance

Common Stock Reserved for Future Issuance

Common stock reserved for future issuance was as follows:

 

 

June 30, 2026

 

Common stock options and restricted stock units

 

 

13,976,293

 

Shares available under the 2015 equity incentive plan

 

 

6,164,361

 

Shares available under the 2022 inducement plan

 

 

167,675

 

Shares available under the employee stock purchase plan

 

 

537,999

 

 

 

 

20,846,328

 
Summary of Stock Option Activity

The following table summarizes our stock option activity under all equity incentive plans for the six months ended June 30, 2026:

 

 

 

Number of
Outstanding
Stock Options

 

 

Weighted-
Average
Exercise Price

 

Outstanding as of December 31, 2025

 

 

9,591,504

 

 

$

3.82

 

Granted

 

 

4,274,091

 

 

$

0.73

 

Canceled/forfeited/expired

 

 

(296,519

)

 

$

8.00

 

Outstanding as of June 30, 2026

 

 

13,569,076

 

 

$

2.75

 
Schedule of Restricted Stock Units Activity

The following table summarizes our restricted stock unit activity under all equity incentive plans for the six months ended June 30, 2026:

 

 

Number of Outstanding
Restricted Stock Units

 

 

Weighted-Average
Grant Date
Fair Value

 

Balance as of December 31, 2025

 

 

20,108

 

 

$

5.52

 

Granted

 

 

446,940

 

 

$

0.71

 

Released

 

 

(20,108

)

 

$

5.52

 

Cancelled

 

 

(39,723

)

 

$

0.71

 

Balance as of June 30, 2026

 

 

407,217

 

 

$

0.71

 

 
Schedule of Allocation of Stock-Based Compensation for All Options and Restricted Stock Units and Stock Issued Pursuant to Our Employee Stock Purchase Plan

The allocation of stock-based compensation for all options and restricted stock units and stock issued pursuant to our employee stock purchase plan is as follows (in thousands):

 

 

Three Months Ended June 30,

 

 

Six Months Ended June 30,

 

 

 

2026

 

 

2025

 

 

2026

 

 

2025

 

Research and development

 

$

264

 

 

$

325

 

 

$

547

 

 

$

629

 

General and administrative

 

 

881

 

 

 

980

 

 

 

1,905

 

 

 

1,854

 

Total stock-based compensation expense

 

$

1,145

 

 

$

1,305

 

 

$

2,452

 

 

$

2,483

 
Employee Stock Option [Member]  
Summary of Assumptions Used to Determine Fair Value of Employee Stock Option Grants and Performance Options with Market Condition

The assumptions used in the Black-Scholes option pricing model to determine the fair value of the employee stock option grants were as follows:

 

 

Three Months Ended June 30,

 

Six Months Ended June 30,

 

 

2026

 

2025

 

2026

 

2025

Expected term (in years)

 

5.50

 

5.50 – 6.00

 

5.50 – 6.08

 

5.50 – 6.08

Risk-free interest rate

 

4.2%

 

3.9% – 4.1%

 

3.7% – 4.2%

 

3.9% – 4.5%

Expected volatility

 

107.5%

 

76.9% – 77.5%

 

105.5% – 107.5%

 

75.9% – 77.5%

Expected dividend yield

 

0.0%

 

0.0%

 

0.0%

 

0.0%