9. Stock-Based Compensation

During the three months ended September 30, 2020 the shareholders approved the 2020 Equity Incentive Plan. The 2020 Plan provides for the grant of nonqualified stock options, incentive stock options, restricted stock, restricted stock units, stock appreciation rights (SARs), and performance share awards to employees, officers, consultants, advisors, non-employee directors and independent contractors designated by either the board of directors of the Company or if so authorized by the board of directors, the Compensation Committee (the “Committee”) of the Board of Directors. Under the 2020 Plan, the maximum number of shares of common stock which may be issued, subject to adjustment as described below, is 1,902,520 shares of common stock, which includes 2,520 shares that have been rolled over from our 2012 Plan, as amended.

A summary  of the Company’s outstanding stock option activity for the nine months ended September 30, 2020 is as follows:

The Company estimates the fair value of each stock option on the grant date using the Black-Scholes-Merton valuation model, which requires several estimates including an estimate of the fair value of the underlying common stock on grant date. The expected volatility was based on an average of the historical volatility the Company. The expected term was calculated utilizing the simplified method. The risk-free interest rate was based on the U.S. Treasury yield curve in effect at the time of grant for the expected term of the option. The following weighted average assumptions were used in the calculation to estimate the fair value of options granted to employees during the nine months ended September 30, 2020.

Unrecognized stock-based compensation as of September 30, 2020 is as follows (in thousands):