Schedule of Fair Value Assumptions |
The Company estimates the fair value of each stock award on the grant date using the Black-Scholes option-pricing model based on the following assumptions:
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Years Ended December 31, |
|
|
2021 |
|
2020 |
Risk free interest rate |
|
0.46% - 1.20% |
|
0.33% - 1.53% |
Expected term (in years) |
|
5.31 - 5.73 |
|
5 - 5.73 |
Dividend yield |
|
— |
|
|
— |
|
Expected volatility |
|
75.0% - 81.7% |
|
70.0% - 75.8% |
The fair value of shares expected to be purchased under the 2018 ESPP was determined using the Black-Scholes model with the following assumptions:
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Years Ended December 31, |
|
|
2021 |
|
2020 |
Risk free interest rate |
|
0.04% - 0.10% |
|
0.10% - 0.18% |
Expected term (in years) |
|
0.5 years |
|
0.5 years |
Dividend yield |
|
— |
|
|
— |
|
Expected volatility |
|
60.46% - 131.21% |
|
74.36% - 120.89% |
|
Schedule of Stock Option Activity |
The following table summarizes stock option activity for employees and non-employees:
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Number of Options |
|
Weighted- Average Exercise Price |
|
Weighted- Average Remaining Contractual Life |
|
Aggregate Intrinsic Value (in thousands) |
Outstanding, December 31, 2020 |
9,591,123 |
|
|
$ |
3.44 |
|
|
|
|
$ |
2,303 |
|
Granted |
2,822,696 |
|
|
3.05 |
|
|
|
|
— |
|
Exercised |
482,115 |
|
|
2.14 |
|
|
|
|
1,106 |
|
Canceled |
379,991 |
|
|
4.96 |
|
|
|
|
102 |
|
Outstanding, December 31, 2021 |
11,551,713 |
|
|
$ |
3.34 |
|
|
6.71 years |
|
$ |
11,402 |
|
Vested or expected to vest, December 31, 2021 |
11,551,713 |
|
|
$ |
3.34 |
|
|
6.71 years |
|
$ |
11,402 |
|
Exercisable, December 31, 2021 |
7,376,177 |
|
|
$ |
3.45 |
|
|
5.52 years |
|
$ |
7,964 |
|
The following table summarizes stock option activity for these inducement options (in thousands):
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Number of Options |
|
Weighted- Average Exercise Price |
|
Weighted- Average Remaining Contractual Life |
|
Aggregate Intrinsic Value (in thousands) |
Outstanding, December 31, 2020 |
420,313 |
|
|
$ |
5.00 |
|
|
|
|
$ |
— |
|
Granted |
360,000 |
|
|
$ |
3.48 |
|
|
|
|
$ |
— |
|
Canceled or Expired |
120,313 |
|
|
$ |
5.87 |
|
|
|
|
$ |
— |
|
Outstanding, December 31, 2021 |
660,000 |
|
|
$ |
4.01 |
|
|
8.71 years |
|
$ |
108 |
|
Vested or expected to vest, December 31, 2021 |
660,000 |
|
|
$ |
4.01 |
|
|
8.71 years |
|
$ |
108 |
|
Exercisable, December 31, 2021 |
168,750 |
|
|
$ |
4.65 |
|
|
7.66 years |
|
$ |
— |
|
|
Schedule of Stock-Based Compensation Expense |
Total stock-based compensation expense is recorded in operating expenses based upon the functional responsibilities of the individuals holding the respective options as follows (in thousands):
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Years Ended December 31, |
|
|
2021 |
|
2020 |
Research and development |
|
$ |
2,274 |
|
|
$ |
2,394 |
|
General and administrative |
|
2,941 |
|
|
2,696 |
|
Total stock-based compensation |
|
$ |
5,215 |
|
|
$ |
5,090 |
|
|