15. Stock-Based Compensation

The Company’s stock-incentive program is a long-term retention program that is intended to attract, retain and provide incentives for talented employees, officers and directors, and to align stockholder and employee interests. Currently, the Company is able to grant options, stock appreciation rights (“SARs”) and restricted shares from the Interpace Biosciences, Inc. 2019 Equity Incentive Plan. No new grants may be made under the Company’s prior stock incentive plan, the Interpace Diagnostics Group, Inc. (now known as Interpace Biosciences, Inc.) Amended and Restated 2004 Stock Award and Incentive Plan (the “2004 Plan”). Unless earlier terminated by action of the Company’s board of directors, the 2004 Plan will remain in effect until such time as no stock remains available for delivery and the Company has no further rights or obligations under the 2004 Plan with respect to outstanding awards thereunder.

Historically, stock options have been granted with an exercise price equal to the market value of the common stock on the date of grant, expire 10 years from the date they are granted, and generally vested over a one to three-year period for employees and members of the Board. Upon exercise, new shares will be issued by the Company. The restricted shares and restricted stock units (“RSUs”) granted to employees generally have a three-year graded vesting period and are subject to accelerated vesting and forfeiture under certain circumstances. Restricted shares and RSUs granted to Board members generally have a three-year graded vesting period and are subject to accelerated vesting and forfeiture under certain circumstances.

The Company primarily uses the Black-Scholes option-pricing model to determine the fair value of stock options. The determination of the fair value of stock-based payment awards on the date of grant using an option-pricing model is affected by the Company’s stock price as well as assumptions regarding a number of complex and subjective variables. These variables include the Company’s expected stock price volatility over the term of the awards, actual and projected employee stock option exercise behaviors, risk-free interest rate and expected dividends. Expected volatility is based on historical volatility. As there is no trading volume for the Company’s options, implied volatility is not representative of the Company’s current volatility so the historical volatility of the Company’s common stock is determined to be more indicative of the Company’s expected future stock performance. The expected life is determined using the safe-harbor method. The Company expects to use this simplified method for valuing employee options until more detailed information about exercise behavior becomes available over time. The Company bases the risk-free interest rate on U.S. Treasury zero-coupon issues with remaining terms similar to the expected term on the options. The Company does not anticipate paying any cash dividends in the foreseeable future and therefore uses an expected dividend yield of zero in the option valuation model. The Company estimates forfeitures at the time of grant and revise those estimates in subsequent periods if actual forfeitures differ from those estimates. The Company uses historical data to estimate pre-vesting option forfeitures and records stock-based compensation expense only for those awards that are expected to vest. The Company recognizes compensation cost, net of estimated forfeitures, arising from the issuance of stock options on a straight-line basis over the vesting period of the grant.

The Company began an employee stock purchase plan in 2020 and recognized approximately $46,000 and $0.1 million in expense related to that plan for the years ended December 31, 2022 and 2021, respectively. The Company suspended its plan in July 2022 as there were no shares available in the original authorized shares pool. In November 2022, the shareholders approved an increase to the pool of an additional one million shares.

As of December 31, 2022, we have reserved 776,849 shares of our common stock for issuance under our 2019 Equity Incentive Plan and 1,000,007 shares of our common stock for issuance under our Employee Stock Purchase Plan and 1,672,746 additional shares available for future grants of awards under our 2019 Equity Incentive Plan.

The estimated compensation cost associated with the granting of restricted stock and restricted stock units is based on the fair value of the Company’s common stock on the date of grant. The Company recognizes the compensation cost, net of estimated forfeitures, arising from the issuance of restricted stock and restricted stock units on a straight-line basis over the shorter of the vesting period or the period from the grant date to the date when retirement eligibility is achieved.

The following table provides the weighted average assumptions used in determining the fair value of the stock options granted during the years ended December 31, 2022 and December 31, 2021:

Schedule of Stock Options, Valuation Assumptions

The weighted-average fair value of stock options granted during the year ended December 31, 2022 was estimated to be $4.50. The weighted-average fair value of stock options granted during the year ended December 31, 2021 was estimated to be $4.64. There were no options exercised in 2022. There were 13,042 options exercised in 2021.

Stock-based compensation from continuing operations for the years ended December 31, 2022 and 2021 is as follows: 

 Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award

A summary of stock option activity for the year ended December 31, 2022, and changes during such year, is presented below:

 Schedule of Stock Option Activity

A summary of the change in of the Company’s non-vested options for the year ended December 31, 2022 is presented below: 

 Schedule of Non Vested Option Activity

The aggregate fair value of options vested during the years ended December 31, 2022 and 2021 was $0.7 million and $0.8 million, respectively. The weighted-average grant date fair value of options vested during the year ended December 31, 2021 was $6.54.

A summary of the Company’s non-vested shares of restricted stock and restricted stock units for the year ended December 31, 2022, and changes during such year, is presented below:

 Schedule of Share-Based Compensation, Restricted Stock and Restricted Stock Units Activity

The aggregate fair value of restricted stock units vested during each of the years ended December 31, 2022 and 2021 was $0.6 million and $0.3 million, respectively.

As of December 31, 2022, there was approximately $0.9 million of total unrecognized compensation cost, net of estimated forfeitures, related to unvested stock options and restricted stock units which will be expensed over the next three years.