​

The Company maintains the Axogen 2010 Stock Incentive Plan, as amended and restated (the “Axogen Plan”), which allows for issuance of incentive stock options, non-qualified stock options, performance stock units (“PSUs”) and restricted stock units (“RSUs”) to employees, directors and consultants at exercise prices not less than the fair market value at the date of grant. At the 2017 Annual Meeting of Shareholders held on May 24, 2017, the Axogen Plan was

amended to increase the number of shares of common stock authorized for issuance under the Axogen Plan to 7,700,000 shares. As of June 30, 2019, 423,094 shares of common stock were available for issuance under the Axogen Plan.

​

At the 2017 Annual Meeting of Shareholders, the shareholders approved the adoption of the Axogen 2017 Employee Stock Purchase Plan (the “2017 ESPP”), which allows for eligible employees to acquire shares of the Company’s common stock through payroll deductions at a discount from market value. The 2017 ESPP authorized a total of 600,000 shares of the Company’s common stock to be provided under the plan. As of June 30, 2019, 486,563 shares of common stock were available for issuance under the 2017 ESPP.

​

The options granted to employees prior to July 1, 2017 typically vest 25% one year after the grant date and 12.5% every six months thereafter for the remaining three-year period until fully vested after four years. The options granted to employees after July 1, 2017 typically vest 50% two years after the grant date and 12.5% every six months thereafter for the remaining two-year period until fully vested after four years. The options granted to directors and certain options granted from time to time to certain executive officers have vested ratably over three years, 25% per quarter over one year or had no vesting period. Options typically have terms ranging from seven to ten years.

​

The Company recognized stock-based compensation expense, which consisted of compensation expense related to employee stock options, PSUs, RSUs and the 2017 ESPP based on the value of share-based payment awards that are ultimately expected to vest during the period, of approximately $2,674 and $2,041 for the three months ended June 30, 2019 and 2018, respectively and approximately $4,989 and $3,770 for the six months ended June 30, 2019 and 2018, respectively.

​

The Company estimates the fair value of each option award issued under such plans on the date of grant using a Multiple Point Black-Scholes option-pricing model which uses a weighted average of historical volatility and peer company volatility. The Company determines the expected life of each award giving consideration to the contractual terms, vesting schedules and post-vesting forfeitures. The Company uses the risk-free interest rate on the implied yield currently available on U.S. Treasury issues with an equivalent remaining term approximately equal to the expected life of the award.

​

The Company used the following weighted-average assumptions for options granted during the periods indicated:

​

​

The Company granted stock-based awards for 285,091 shares of its common stock pursuant to the Axogen Plan during the six months ended June 30, 2019. The weighted average fair value of the awards granted at market during the six months ended June 30, 2019 and 2018 was $19.13 and $24.45 per award, respectively.

​

At June 30, 2019, the total future stock compensation expense related to non-vested awards is expected to be approximately $23,180.