v3.26.1
Stock-Based Compensation (Tables)
 6 Months Ended
Jun. 30, 2026
Share-Based Payment Arrangement [Abstract]  
Schedule of Stock Option Activity
The following table summarizes stock option activity, including performance-based stock options (“PBSOs”), under our equity incentive plans during the six months ended June 30, 2026:
Stock Options and PBSOs
Weighted-
Average
Exercise Price		Weighted-
Average
Remaining
Contractual
Term (years)
Aggregate
Intrinsic Value (in thousands)(1)
Outstanding as of December 31, 202512,511,072$5.49 7.6$466 
Options granted3,472,9271.80 
Options exercised(15,456)1.34 
Options cancelled or forfeited(174,210)3.49 
Outstanding as of June 30, 202615,794,333$4.70 7.6$913 
Exercisable as of June 30, 20268,359,997$6.66 6.5$375 
Vested and expected to vest as of June 30, 202615,794,333$4.70 7.6$913 
(1)The aggregate intrinsic value is calculated as the difference between the stock option exercise price and the estimated fair value of the underlying common stock as of the end of each reporting period referenced above.
Schedule of Estimated Fair Value of Stock Options on the Grant Date Using Black-Scholes Option-Pricing Model
We estimated the fair value of each employee stock option award on the grant date using the Black-Scholes option-pricing model based on the following assumptions:
Three Months Ended June 30,Six Months Ended June 30,
2026202520262025
Volatility—
88.4%
89.9% to 90.6%
86.1% to 89.7%
Expected term (in years)—
6.0
5.0 to 6.0
5.0 to 6.0
Risk-free interest rate—
4.2%
3.7% to 3.8%
4.2% to 4.6%
Expected dividend yield—0.0%
0.0%
0.0%
Schedule of Restricted Stock Units Activity (RSUs)
During the six months ended June 30, 2026, we granted 1,220,599 RSUs under the 2021 Plan to employees. A summary of the status of and change in unvested RSUs as of June 30, 2026, was as follows:
Number of Shares Underlying Outstanding RSUs
Weighted-Average Grant Date Fair Value per RSU
Unvested, December 31, 20252,173,234$2.74 
Granted1,220,5991.80
Vested(403,052)3.42
Forfeited(93,288)1.78
Unvested, June 30, 20262,897,493$2.28 
Schedule of Stock-Based Compensation Expenses Recorded in the Condensed Consolidated Statements of Operations and Comprehensive Loss
We recorded stock-based compensation expense related to employee equity-based awards grants as follows (in thousands):
Three Months Ended June 30,Six Months Ended June 30,
2026202520262025
Research and development$1,142 $1,298 $2,267 $3,041 
General and administrative1,335 1,831 2,567 3,970 
Total$2,477 $3,129 $4,834 $7,011 
Schedule of Stock-Based Compensation Expense Related to Equity-Based Awards
The above stock-based compensation expense related to the following equity-based awards (in thousands):
Three Months Ended June 30,Six Months Ended June 30,
2026202520262025
Stock options$1,779 $2,645 $3,445 $5,820 
RSUs604 383 1,178 968 
ESPP94 101 211 223 
Total$2,477 $3,129 $4,834 $7,011