XML 38 R28.htm IDEA: XBRL DOCUMENT v3.24.1.u1
Stock-Based Compensation (Tables)
3 Months Ended
Mar. 31, 2024
Share-Based Payment Arrangement [Abstract]  
Stock Option Valuation The following table presents, on a weighted average basis, the assumptions used in the Black-Scholes option-pricing model to determine the grant-date fair value of stock options granted to employees, directors and non-employees.
Three Months Ended March 31,
20242023
Risk-free interest rate4.1 %3.6 %
Expected term (in years)6.16.0
Expected volatility95.7 %90.8 %
Expected dividend yield%%
Summary of Stock Option Activity
The following table summarizes the Company’s stock option activity for the three months ended March 31, 2024:
Number of
Shares
Weighted
Average
Exercise
Price
Weighted
Average
Contractual
Term (Years)
Aggregate
Intrinsic
Value (in thousands)
Outstanding as of December 31, 20236,008,541 $2.97 8.6$24 
Granted2,387,467 0.93 
Forfeited and Expired(313,170)2.11 
Outstanding as of March 31, 20248,082,838 $2.40 8.8$2,123 
Exercisable as of March 31, 20241,535,408 $7.44 6.0$113 
Vested and expected to vest as of March 31, 20246,136,867 $2.79 8.6$1,501 
Share-based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity
Restricted Stock Units— The following table summarizes the Company's restricted stock unit activity for the three months ended March 31, 2024:
Number of
Shares
Unvested as of December 31, 20233,118,824 
Granted5,882,459 
Vested(503,186)
Forfeited(126,511)
Unvested as of March 31, 20248,371,586 
Summary of Stock-Based Compensation Expense Classification
Stock-based compensation expense was classified in the condensed consolidated statements of operations and comprehensive loss as follows:
Three Months Ended March 31,
(in thousands)20242023
Research and development expense$783 $831 
Selling, general and administrative expense956 814 
Total stock-based compensation$1,739 $1,645 
Share-Based Payment Arrangement, Option and Stock Appreciation Rights, Activity