For the three-month periods ended September 30, 2022 and 2021, our total stock-based compensation expense, which includes reversals of expense for certain forfeited or cancelled awards, was $41,052 and $108,157, respectively. For the nine-month periods ended September 30, 2022 and 2021, our total stock-based compensation expense, which includes reversals of expense for certain forfeited or cancelled awards, was $266,456 and $371,635, respectively. We have not recorded any income tax benefit related to stock-based compensation in any of the three-month or nine-month periods ended September 30, 2022 and 2021.

A summary of the status of our stock options as of September 30, 2022, and changes during the nine-month period then ended, is presented below.

The weighted average grant date fair value per stock option granted during the nine-month period ended September 30, 2022 was $0.65. Key assumptions used in the Black-Scholes option pricing model for stock options granted during the nine-month period ended September 30, 2022 were the Company’s stock price, an expected volatility rate of 93.94%, a risk-free rate of 2.34%, and an expected life of 6.25 years. 

A summary of the status of our unvested restricted stock as of September 30, 2022, and changes during the nine-month period then ended, is presented below.

As of September 30, 2022, there was $106,476 of total unrecognized compensation expense related to unvested stock-based awards, which we expect to recognize over the remaining weighted average vesting term of 1.5 years.