v3.26.1
Stock-Based Awards
 6 Months Ended
Jun. 30, 2026
Share-Based Payment Arrangement [Abstract]  
Stock-Based Awards Stock-Based Awards
The Company has issued stock-based awards from various equity incentive and stock purchase plans, as more fully described in Note 9, "Stock-Based Awards" to the consolidated financial statements in the Company's 2025 Annual Report on Form 10-K.
Stock Option Activity
The following table summarizes stock option activity for the six months ended June 30, 2026:
Number of Options
Weighted-Average
Exercise Price
Balance at December 31, 202521,326,333 $26.39 
Granted
2,601,349 16.84 
Exercised
(992,867)15.81 
Forfeited
(698,185)21.15 
Expired
(893,471)34.89 
Balance at June 30, 202621,343,159 $25.53 
Vested and expected to vest at June 30, 202621,343,159 $25.53 
Exercisable at June 30, 202614,065,727 $28.80 

The estimated fair value of stock options granted to employees were calculated using the Black-Scholes option-pricing model using the following assumptions:

Six Months Ended June 30,
20262025
Expected term (in years)
5.50 - 6.08
5.50 - 6.08
Volatility
61.7% - 66.7%
64.8% - 68.7%
Risk-free interest rate
3.7% - 4.3%
3.7% - 4.5%
Dividend yield
——
Restricted Stock Activity
The following table summarizes restricted stock unit ("RSU") activity for the six months ended June 30, 2026:
Number of RSU sharesWeighted-Average Fair Value at Date of Grant per Share
Unvested at December 31, 20255,124,629 $21.74 
Granted3,385,121 16.52 
Vested and released(1,341,956)23.92 
Forfeited(563,254)19.84 
Unvested and expected to vest at June 30, 20266,604,540 $18.78 
Stock-Based Compensation Expense
The Company’s results of operations include expenses relating to stock-based compensation as follows (in thousands):
Three Months Ended June 30,Six Months Ended June 30,
2026202520262025
Research and development
$13,453 $15,188 $27,047 $30,325 
General and administrative
9,462 10,199 18,955 20,222 
Total
$22,915 $25,387 $46,002 $50,547