NOTE 9 - STOCK OPTION PLANS

Our stock-based employee compensation plans are described below:

2015 Equity Incentive Plan

Under our 2015 Equity Incentive Plan, as amended, up to 10,000,000 shares of our authorized but unissued common stock are reserved for issuance to employees, consultants, or to non-employee members of the Board or to any member of the board of directors (or similar governing authority) of any affiliate of the Company. The 2015 Equity Incentive Plan, approved by our stockholders on May 7, 2015, replaced the previously approved stock option plan (the “2005 Equity Incentive Plan”). The maximum contractual term of awards is generally 10 years.

Stock Options: We estimate the fair value of each option award on the date of grant using the Black-Scholes option valuation model. We then recognize the grant date fair value of each option as compensation expense ratably using the straight-line attribution method over the service period (generally the vesting period). The Black-Scholes model incorporates the following assumptions:

We used the following weighted-average assumptions to estimate the fair value of the options granted for the years indicated:

Summarized information for the 2015 Equity Incentive Plan is as follows:

The intrinsic value related to the outstanding options under this plan was $0.7 million, $8.4 million and $46.0 million at December 31, 2019, 2018 and 2017, respectively. The intrinsic value related to the exercisable options under this plan was $0.6 million, $6.0 million and $25.6 million at December 31, 2019, 2018 and 2017, respectively.

The total intrinsic value of the options exercised was $0.4 million, $3.2 million and $0.6 million during 2019, 2018 and 2017, respectively.

Further information regarding options outstanding under the 2015 Equity Incentive Plan at December 31, 2019 is summarized below:

At December 31, 2019, the total compensation cost related to non-vested options not recognized is $14.4 million. The expected weighted average period over which the total compensation costs related to non-vested options is 2.7 years.

Restricted Common Stock: We granted 376,625 shares of restricted common stock to employees during the year ended December 31, 2019. We did not grant any restricted common stock to employees during the years ended December 31, 2018 and 2017.

During the year ended December 31, 2019, 22,000 shares of restricted common stock were forfeited, and no shares became vested.

At December 31, 2019, the total compensation cost related to restricted common stock not recognized is $0.5 million. The expected weighted average period over which the total compensation costs related to restricted common stock is 0.2 years.

2005 Equity Incentive Plan

Under the 2005 Equity Incentive Plan, as amended, shares of our authorized but unissued common stock were reserved for issuance to employees, consultants, or to non-employee members of the Board or to any member of the board of directors (or similar governing authority) of any affiliate of the Company. As of January 20, 2015, no additional shares were available for grant under the 2005 Equity Incentive Plan. A total of 260,000 options were outstanding and exercisable under this plan at December 31, 2019.

Summarized information for the 2005 Equity Incentive Plan is as follows:

The intrinsic value related to the outstanding or exercisable options under this plan was $0, $0.5 million and $1.5 million at December 31, 2019, 2018 and 2017, respectively.

Further information regarding options outstanding under the 2005 Equity Incentive Plan at December 31, 2019 is summarized below: