v3.24.1.u1
Stock-Based Compensation (Tables)
 3 Months Ended
Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]  
Stock-Based Compensation Expense
The following stock-based compensation expense was recognized for the periods indicated (in thousands):
Three Months Ended March 31,
20242023
Research and development$2,829 $2,461 
Selling, general and administrative2,724 2,372 
Total stock-based compensation expense$5,553 $4,833 
Valuation Assumptions Using the Black-Scholes Option-Pricing Model
The fair value of each option award is estimated on the date of grant using the Black-Scholes option-pricing model using the assumptions in the following table for options issued during the period indicated:
Three Months Ended March 31,
20242023
Expected dividend yield0%0%
Expected volatility
94.9% -95.5%
92.6% - 94.3%
Risk-free interest rate
4.0% - 4.4%
3.6% - 4.2%
Expected term6.06 years5.88 years
Schedule of Stock Options Roll Forward
The following table summarizes stock option activity during the three months ended March 31, 2024:
SharesWeighted-
Average
Exercise Price		Weighted-Average
Remaining
Contractual Term
(Years)		Aggregate
Intrinsic
Value
 (in thousands)
Outstanding, December 31, 202312,223,637 $15.11 6.7
Granted1,654,555 17.99 
Exercised(257,683)10.24 
Forfeited(22,343)11.04 
Expired(23,810)23.99 
Outstanding, March 31, 202413,574,356 15.54 6.8$46,445 
As of March 31, 2024:
Exercisable8,150,261 18.58 5.518,242 
Vested and expected to vest12,411,841 15.98 6.640,279 
Schedule of RSU Activity
The following table summarizes RSU activity during the three months ended March 31, 2024:
Shares
Weighted-Average
Grant Date Fair Value
Outstanding, December 31, 2023905,614 $5.97 
Granted591,215 18.30 
Vested(370,891)7.21 
Forfeited(3,828)12.80 
Outstanding, March 31, 20241,122,110 12.03