Stock Based Compensation	3 Months Ended
Mar. 31, 2020
Stock Based Compensation [Abstract]
Stock Based Compensation	Note 5 — Stock Based Compensation We have a stock incentive plan for employees and others called the “VirnetX Holding Corporation 2013 Equity Incentive Plan”, or the Plan, which has been approved by our stockholders. The Plan generally provides for the granting of up to 16,624,469 shares of our common stock, including stock options and stock purchase rights (“RSUs”), and will expire in 2024. As of March 31, 2020, 1,271,039 shares remained available for grant under the Plan. Stock-based compensation expense included in general and administrative expense was $348 and $374, and in research and development expense was $430 and $411, for the three months ended March 31, 2020 and 2019, respectively. During the three months ended March 31, 2020, we granted options for a total of 240,000 shares with a weighted average grant date fair value of $4.30 per option. We estimated the fair value of the options on the date of grant utilizing the Black-Scholes valuation model with the following assumptions: (i) 0 percent dividend yield, (ii) 93.4 percent volatility, (iii) 0.8 percent risk free rate and (iv) 6.25years expected term. There were no options granted during the three months ended March 31, 2019, and no RSUs granted during the three months ended March 31, 2020 or 2019. As of March 31, 2020, the unrecognized stock-based compensation expense related to non-vested stock options and RSUs was $4,088 and $1,581, respectively, which will be amortized over an estimated weighted average period of approximately 2.24 and 2.08 years, respectively.

Note 5 — Stock Based Compensation

We have a stock incentive plan for employees and others called the “VirnetX Holding Corporation 2013 Equity Incentive Plan”, or the Plan, which has been approved by our stockholders. The Plan generally provides for the granting of up to 16,624,469 shares of our common stock, including stock options and stock purchase rights (“RSUs”), and will expire in 2024. As of March 31, 2020, 1,271,039 shares remained available for grant under the Plan.

Stock-based compensation expense included in general and administrative expense was $348 and $374, and in research and development expense was $430 and $411, for the three months ended March 31, 2020 and 2019, respectively.

During the three months ended March 31, 2020, we granted options for a total of 240,000 shares with a weighted average grant date fair value of $4.30 per option. We estimated the fair value of the options on the date of grant utilizing the Black-Scholes valuation model with the following assumptions: (i) 0 percent dividend yield, (ii) 93.4 percent volatility, (iii) 0.8 percent risk free rate and (iv) 6.25years expected term. There were no options granted during the three months ended March 31, 2019, and no RSUs granted during the three months ended March 31, 2020 or 2019.

As of March 31, 2020, the unrecognized stock-based compensation expense related to non-vested stock options and RSUs was $4,088 and $1,581, respectively, which will be amortized over an estimated weighted average period of approximately 2.24 and 2.08 years, respectively.