| 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:
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Years Ended December 31, |
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2020 |
|
2019 |
| Risk free interest rate |
|
0.33% - 1.53% |
|
1.41% - 2.60% |
| Expected term (in years) |
|
5.00 - 5.73 |
|
5 - 5.73 |
| Dividend yield |
|
— |
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|
— |
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| Expected volatility |
|
70.0% - 75.8% |
|
81.7% - 81.8% |
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Years Ended December 31, |
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|
2020 |
|
2019 |
| Risk free interest rate |
|
0.10% - 0.18% |
|
2.48 |
% |
| Expected term (in years) |
|
0.5 years |
|
0.5 years |
| Dividend yield |
|
— |
|
|
— |
|
| Expected volatility |
|
74.36% - 120.89% |
|
57.57 |
% |
|
| Schedule of Stock Option Activity |
The following table summarizes stock option activity for employees and non-employees:
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Number of
Options |
|
Weighted-
Average
Exercise
Price |
|
Weighted-
Average
Remaining
Contractual
Life |
|
Aggregate
Intrinsic
Value
(in thousands) |
| Outstanding, December 31, 2019 |
8,259,915 |
|
|
$ |
3.60 |
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|
|
$ |
7,987 |
|
| Granted |
2,311,481 |
|
|
3.15 |
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|
|
|
— |
|
| Exercised |
149,406 |
|
|
1.95 |
|
|
|
|
97 |
|
| Canceled |
830,867 |
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|
4.58 |
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|
|
101 |
|
| Outstanding, December 31, 2020 |
9,591,123 |
|
|
$ |
3.44 |
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|
6.84 years |
|
$ |
2,303 |
|
| Vested or expected to vest, December 31, 2020 |
9,591,123 |
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$ |
3.44 |
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|
6.84 years |
|
$ |
2,303 |
|
| Exercisable, December 31, 2020 |
6,123,532 |
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$ |
3.28 |
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|
5.81 years |
|
$ |
2,269 |
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|
Number of
Options |
|
Weighted-
Average
Exercise
Price |
|
Weighted-
Average
Remaining
Contractual
Life |
|
Aggregate
Intrinsic
Value
(in thousands) |
| Outstanding, December 31, 2019 |
1,200,000 |
|
|
$ |
4.36 |
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|
|
$ |
130 |
|
| Granted |
— |
|
|
$ |
— |
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|
$ |
— |
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| Canceled or Expired |
779,687 |
|
|
$ |
4.01 |
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|
|
$ |
— |
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| Outstanding, December 31, 2020 |
420,313 |
|
|
$ |
5.00 |
|
|
8.12 years |
|
$ |
— |
|
| Vested or expected to vest |
420,313 |
|
|
$ |
5.00 |
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|
8.12 years |
|
$ |
— |
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| Exercisable, December 31, 2020 |
214,063 |
|
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$ |
5.34 |
|
|
7.60 years |
|
$ |
— |
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| 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):
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Years Ended December 31, |
| |
|
2020 |
|
2019 |
| Research and development |
|
$ |
2,394 |
|
|
$ |
2,446 |
|
| General and administrative |
|
2,696 |
|
|
2,928 |
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| Total stock-based compensation |
|
$ |
5,090 |
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|
$ |
5,374 |
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