Quarterly report pursuant to Section 13 or 15(d)

Stock Plans (Tables)

v3.22.1
Stock Plans (Tables)
3 Months Ended
Mar. 31, 2022
Stock Plans  
Schedule of our option activity

The following table summarizes our option activity:

    

    

    

Weighted

    

Weighted

Average

Average 

Remaining

Aggregate

Exercise

Option

Intrinsic

Options (in

Price per

Term

Value

thousands)

share

(in years)

(in thousands)

Outstanding at December 31, 2021

 

682

$

12.53

 

8.98

$

Granted

 

310

 

1.18

Forfeited or expired

 

(2)

 

531.11

Outstanding at March 31, 2022

 

990

$

8.28

9.07

$

Exercisable at March 31, 2022

 

511

$

14.01

8.71

$

Schedule of the stock-based compensation expense

The following table summarizes the stock-based compensation expense recorded for awards under our stock option plans (in thousands):

Three Months Ended

March 31, 

    

2022

    

2021

Research and development

$

123

$

120

Selling, general and administrative

 

103

 

128

Total stock-based compensation expense

$

226

$

248

Schedule of assumptions to estimate the fair value of options

Three Months Ended

March 31, 

 

    

2022

    

2021

    

Weighted-average risk-free interest rate

 

1.47

%  

0.54

%

Expected dividend payments

 

 

 

Expected holding period (years)(1)

 

5.4

5.5

Weighted-average volatility factor (2)

 

113.2

 

113.9

 

Estimated forfeiture rates for options granted (3)

 

5.14

%  

29.6

%

(1) Expected holding period is based on historical experience of similar awards, giving consideration to the contractual terms of the stock-based awards, vesting schedules and the expectations of future employee behavior.
(2) Weighted average volatility is based on the historical volatility of our common stock.
(3) Estimated forfeiture rates are based on historical data.