Annual report pursuant to Section 13 and 15(d)

Stock and Employee Benefit Plans (Tables)

v3.22.0.1
Stock and Employee Benefit Plans (Tables)
12 Months Ended
Dec. 31, 2021
Share-based Payment Arrangement [Abstract]  
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