Share-based Payment Arrangement [Text Block] | 4. The Company’s 2018 “2018 July 2018. 2018 1,600,000 2018 January 1 2028, 4% December 31, On January 1, 2019, 2018 620,778 1,600,000 2,220,778 January 1, 2020, 2018 1,129,250 1,287,561 2,416,811 2018 March 31, 2020, 1,723,469 2018 The 2018 2016 2004 2016 2004 2018 2016 2004 2016 2004 2016 2004 not 2018 March 31, 2020, 700,553 2016 386,981 2004 2016 2004 Stock-Based Compensation Valuation and Expense The Company accounts for its employee stock-based compensation plans using the fair value method. The fair value method requires the Company to estimate the grant-date fair value of its stock-based awards and amortize this fair value to compensation expense over the requisite service period or vesting term. The fair value of each option grant is estimated using a Black-Scholes option-pricing model. For restricted stock units (“RSUs”), the grant-date fair value is based upon the market price of the Company’s common stock on the date of the grant. This fair value is then amortized to compensation expense over the requisite service period or vesting term. The Company recorded the following stock-based compensation expense: Three Months Ended March 31, By Expense Category: 20 20 201 9 Research and development $ 275,141 $ 271,921 General and administrative 603,822 615,064 Total $ 878,963 $ 886,985 Three Months Ended March 31, By Type of Award: 20 20 201 9 Stock Options $ 854,770 $ 786,241 Restricted Stock Units 24,193 100,744 Total $ 878,963 $ 886,985 The following table summarizes the unamortized compensation expense and the remaining years over which such expense would be expected to be recognized, on a weighted-average basis, by type of award: As of March 31, 20 20 Unamortized Expense Weighted Average Remaining Recognition Period (Years) Stock Options $ 8,419,952 2.82 Restricted Stock Units $ 654,641 3.89 Stock Options The following table summarizes the assumptions used for estimating the fair value of stock options granted under the Black-Scholes option-pricing model during: Three Months Ended March 31, 20 20 201 9 Expected dividend yield — % — % Risk-free interest rate 0.90 % - 1.60 % 2.54 % Expected Volatility 87 % - 90 % 84 % Expected life (years) 6.08 6.08 As a result of using these assumptions in the Black-Scholes option-pricing model, the weighted average fair value per share for options granted during the three March 31, 2020 2019 $2.38 $10.02, The following describes each of these assumptions and the Company’s methodology for determining each assumption: Expected Dividend Yield The dividend yield percentage is zero Risk-Free Interest Rate The risk-free interest rate is based on the U.S. Treasury yield curve approximating the term of the expected life of the award in effect on the date of grant. Expected Volatility Expected stock price volatility is based on a weighted average of several peer public companies and the historical volatility of the Company’s common stock during the period for which it has traded since the initial public offering. For purposes of identifying peer companies, the Company considered characteristics such as industry, length of trading history and similar vesting terms. Expected Life The expected life represents the period the awards are expected to be outstanding. The Company’s historical share option exercise experience does not The following table summarizes the Company’s stock option activity during the three March 31, 2020: Number of Weighted Weighted Aggregate Outstanding as of December 31, 2019 2,052,976 $ 9.33 Granted 557,961 $ 3.33 Exercised (10,079 ) $ 4.61 Cancelled (36,467 ) $ 9.70 Outstanding as of March 31, 20 20 2,564,391 $ 8.04 8.11 $ 1,090,114 Exercisable as of March 31, 2020 987,724 $ 8.09 6.54 $ 294,677 Vested and expected to vest as of March 31, 2020 2,410,706 $ 7.85 8.07 $ 1,088,356 The aggregate intrinsic value of stock options in the table above represents the difference between the $4.71 March 31, 2020 During the three March 31, 2020 2019, 10,079 15,695 Restricted Stock Unit Awards During the three March 31, 2020, 138,464 four A summary of nonvested RSU awards outstanding as of March 31, 2020 three Number of RSUs Weighted Average Grant-Date Fair Value (per RSU) Nonvested as of December 31, 2019 7,493 $ 28.87 Granted 138,464 3.31 Vested (702 ) 28.87 Forfeited (0 ) 0.00 Nonvested as of March 31, 2020 145,255 $ 4.50 Employee Stock Purchase Plan On May 8, 2019, 2019 March 31, 2020, 446,731 $25,000 six March September September 3, 2019. 85% During the Company’s first September 1, 2019 February 28, 2019, 85% $4.13 February 28, 2020, 3,269 |