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Stockholders' Equity (Tables)
 3 Months Ended
Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]  
Summary of Stock Option Activity
Stock option activity for employee and non-employee awards and related information is as follows (in thousands, except per share data):
Number of
Options		Weighted-
Average
Exercise
Price Per
Share
Outstanding at December 31, 202312,495$14.91 
Granted1,76710.37 
Exercised(541)7.21 
Forfeited/expired(236)16.83 
Outstanding at March 31, 202413,485$14.59 
Schedule of Unvested Restricted Stock Units Roll Forward
The following table summarizes the RSU activity for the three months ended March 31, 2024 (in thousands, except per share data):
Number of SharesWeighted-Average Grant Date Fair Value
Unvested at December 31, 2023758 $18.73 
Granted845 10.53 
Vested(135)22.42 
Forfeited(53)15.69 
Unvested at March 31, 2024
1,415 $13.60 
Schedule of Share-Based Payment Award, Stock Options, Valuation Assumptions
The assumptions used in the Black-Scholes-Merton model to determine the fair value of stock option grants were as follows:
Options
Three Months Ended March 31,
20242023
Risk-free interest rate
3.9% - 4.3%
3.5% - 4.0%
Expected volatility
79% - 80%
81% - 82%
Expected term (in years)
6.0 - 6.1
6.0 - 6.1
Expected dividend yield—%—%
Schedule of Allocated Stock-based Compensation Expense
The allocation of stock-based compensation expense for stock option, RSU awards, PSU awards, and shares purchasable under the ESPP was as follows (in thousands):
Three Months Ended March 31,
20242023
Research and development expense$5,737 $5,272 
General and administrative expense4,569 3,832 
Total stock-based compensation expense$10,306 $9,104