XML 31 R20.htm IDEA: XBRL DOCUMENT v3.22.2
Stock-Based Compensation (Tables)
6 Months Ended
Jun. 30, 2022
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 June 30,Six Months Ended June 30,
2022202120222021
Research and development$2,658 $3,058 $5,050 $5,785 
Selling, general and administrative2,642 3,012 5,524 5,571 
Total stock-based compensation expense$5,300 $6,070 $10,574 $11,356 
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:
Six Months Ended June 30,
20222021
Expected dividend yield0%0%
Expected volatility
87.8% -89.7%
86.2% - 86.7%
Risk-free interest rate
1.4% - 3.6%
0.6% - 1.4%
Expected term5.95 years6.25 years
Schedule of Stock Options Roll Forward
The following table summarizes stock option activity during the six months ended June 30, 2022:
SharesWeighted-
Average
Exercise Price
Weighted-Average
Remaining
Contractual Term
(Years)
Aggregate
Intrinsic
Value
 (in thousands)
Outstanding, December 31, 20218,373,921 $21.47 6.6
Granted2,685,197 9.50 
Exercised(80,721)1.48 
Forfeited(267,563)16.32 
Expired(210,079)23.08 
Outstanding, June 30, 202210,500,755 $18.66 7.0$80 
As of June 30, 2022:
Exercisable5,930,958 $22.57 5.474 
Vested and expected to vest9,719,165 $19.00 6.879 
Schedule of RSU Activity
The following table summarizes RSU activity during the six months ended June 30, 2022:
Shares
Weighted-Average
Grant Date Fair Value
Outstanding, December 31, 202121,500 $25.97 
Granted314,372 10.13 
Exercised(8,465)26.69 
Forfeited(20,099)10.15 
Outstanding, June 30, 2022307,308 10.78