Quarterly report pursuant to Section 13 or 15(d)

Stock Plans

v3.21.2
Stock Plans
9 Months Ended
Sep. 30, 2021
Stock Plans  
Stock Plans

2.    Stock Plans

The following table summarizes 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, 2020

 

28

$

242.70

 

6.35

$

Granted

 

670

 

4.02

Forfeited or expired

 

(6)

 

137.74

Outstanding at September 30, 2021

 

692

$

12.46

9.23

$

Exercisable at September 30, 2021

 

415

$

18.08

9.15

$

No options to purchase common stock were granted during the three-month period ended September 30, 2021.

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

Three Months Ended

Nine Months Ended

(in thousands)

September 30, 

September 30, 

    

2021

    

2020

    

2021

    

2020

Research and development

$

325

$

$

659

$

Selling, general and administrative

 

330

 

9

 

691

 

4

Total stock-based compensation

$

655

$

9

$

1,350

$

4

We use the Black-Scholes-Merton option-pricing model with the following assumptions to estimate the fair value of our stock options:

Three Months Ended

Nine Months Ended

 

September 30, 

 

September 30, 

 

    

2021

    

2020

    

2021

    

2020

 

Weighted-average risk-free interest rate

 

%  

0.3

%

0.5

%  

0.4

%

Expected dividend payments

 

 

 

 

Expected holding period (years) 1

 

5.7

5.5

5.8

Weighted-average volatility factor 2

 

 

1.07

 

1.14

 

1.04

Estimated forfeiture rates for options granted 3

 

%  

24

%

30

%  

27

%

(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.

As of September 30, 2021, there was approximately $0.6 million of total unrecognized compensation expense related to non-vested stock options. This expense is expected to be recognized over a weighted-average period of approximately 1.3 years.