Quarterly report pursuant to Section 13 or 15(d)

Stock Based Compensation (Tables)

v3.21.2
Stock Based Compensation (Tables)
 6 Months Ended
Jun. 30, 2021
Share-based Payment Arrangement [Abstract]  
Schedule of Stock-based Compensation Expense The amount of stock-based compensation expense recognized for the three and six months ended June 30, 2021 and 2020 was as follows (in thousands): 
  Three Months Ended June 30, Six Months Ended June 30,
  2021 2020 2021 2020
Research and development $ 467  $ 391  $ 765  $ 772 
General and administrative 2,503  2,308  3,548  2,988 
Sales and marketing 104  87  209  142 
Total stock-based compensation $ 3,074  $ 2,786  $ 4,522  $ 3,902 
Summary of Option Activity A summary of option activity for the six months ended June 30, 2021 is as follows:
  Options Outstanding
  Number of shares Weighted average exercise price per share Weighted average grant date fair value per share Weighted average remaining contractual term (in years)
Balance at December 31, 2020 8,830,674  $ 3.95  $ 2.36  7.7
Granted 4,048,563  $ 3.33  $ 2.19 
Exercised (580,617) $ 2.70  $ 1.74 
Forfeited (313,841) $ 3.82  $ 2.41 
Expired (339,369) $ 4.55  $ 2.70 
Balance at June 30, 2021 11,645,410  $ 3.78  $ 2.32  8.5
Exercisable at June 30, 2021 3,939,679  $ 4.29  $ 2.44  7.5
The following table summarizes the Company’s market-based option activity for the six months ended June 30, 2021 (in thousands except, for share amounts):
  Options Outstanding
  Number of shares Weighted average exercise price per share Weighted average remaining contractual term (in years) Aggregate intrinsic value (1)
Balance at December 31, 2020 1,000,000  $ 3.29  9.5 $ 65 
Granted —  $ — 
Balance at June 30, 2021 1,000,000  $ 3.29  3.0 $ 380 
Exercisable at June 30, 2021 1,000,000  $ 380 
    
(1) The aggregate intrinsic value in the above table represents the total pre-tax amount that a participant would receive if the option had been exercised on the last day of the respective fiscal period. Options with a market value less than its exercise value are not included in the intrinsic value amount.
Schedule of Fair Value Assumptions for Options
The following table shows the assumptions used to compute stock-based compensation expense for stock options with service-based vesting conditions granted under the Black-Scholes valuation model for the six months ended June 30, 2021:
Service-based options  
Expected annual dividend yield   —%
Expected stock price volatility  
73.0% - 86.5%
Expected term of option (in years)  
0.76 - 6.25
Risk-free interest rate  
0.07% - 1.23%
Nonvested Restricted Stock Shares Activity The following table summarizes the Company’s restricted stock unit (“RSU”) activity for the six months ended June 30, 2021:
  RSUs Outstanding
  Number of shares Weighted average grant date fair value
Unvested RSUs at December 31, 2020 155,833  $ 4.91 
Vested (77,917)
Unvested RSUs at June 30, 2021 77,916  $ 4.91