v3.24.3
Stock-based Compensation
 9 Months Ended
Sep. 30, 2024
Share-Based Payment Arrangement [Abstract]  
Stock-based Compensation Stock-based Compensation
Total compensation cost recognized for all stock-based compensation awards in the condensed consolidated statements of operations was as follows (in thousands):
Three Months Ended
September 30,		Nine Months Ended
September 30,
2024202320242023
Research and development$2,048 $2,571 $7,081 $7,182 
General and administrative2,754 2,160 10,316 7,271 
Total stock-based compensation expense$4,802 $4,731 $17,397 $14,453 
Restricted Stock Unit Awards
The following is a summary of restricted stock unit awards activity for the nine months ended September 30, 2024:
SharesWeighted Average Grant Date Fair Value Per Share
Unvested restricted stock unit awards as of December 31, 20232,107,147$11.96 
Issued1,480,895$9.28 
Vested(676,466)$12.49 
Forfeited(371,120)$14.58 
Unvested restricted stock unit awards as of September 30, 20242,540,456$9.87 
The restricted stock units issued in the nine months ended September 30, 2024 include 422,000 units granted to certain employees that contain performance-based vesting provisions. The expense related to the performance-based vesting of restricted stock units was $3.5 million for the nine months ended September 30, 2024. There was no expense related to the performance-based vesting of restricted stock units for the nine months ended September 30, 2023.
As of September 30, 2024, total unrecognized compensation expense related to unvested restricted stock unit awards was $14.4 million, which the Company expects to recognize over a remaining weighted-average period of 2.57 years.
Stock Options
The following is a summary of stock option activity for the nine months ended September 30, 2024:
SharesWeighted Average
Exercise Price		Remaining
Contractual Life (years)		Aggregate Intrinsic
Value
Outstanding at December 31, 20236,149,645$16.47 6.89$3,195 
Granted2,861,411 $8.27 
Exercised(21,975)$8.72 
Cancelled(821,137)$24.86 
Outstanding at September 30, 20248,167,944$14.52 7.74$13 
Exercisable at September 30, 20243,690,879$20.74 6.27$13 
As of September 30, 2024, total unrecognized compensation expense related to stock options was $27.5 million, which the Company expects to recognize over a remaining weighted-average period of 2.8 years.