8. Stock-Based Compensation

The Company has a 2016 Consolidated Stock Incentive Plan (the “2016 Plan”) and a 2019 Stock Incentive Plan (the “2019 Plan”), which provide for the issuance of incentive and non-incentive stock options, restricted and unrestricted stock awards, stock unit awards and stock appreciation rights. Options and restricted stock units granted generally vest over a period of one to four years and have a maximum term of ten years from the date of grant.  Upon completion of the Ohr Acquisition, the Company assumed the awards outstanding under the NeuBase Therapeutics, Inc. 2018 Equity Incentive Plan.

As of September 30, 2019, an aggregate of 3,100,000 shares of common stock were authorized under the 2019 Plan, subject to an “evergreen” provision that will automatically increase the maximum number of shares of Common Stock that may be issued under the term of the 2019 Plan. As of September 30, 2019, 152,248 common shares were available for future grants under the 2019 Plan. As of September 30, 2019, 291,667 shares of common stock were authorized under the 2016 Plan and 147,041 common shares were available for future grants under the 2016 Plan.

Stock Options

Below is a table summarizing the options issued and outstanding as of and for the year ended September 30, 2019:

 

 

As of September 30, 2019, the unrecognized compensation costs of $7.1 million will be recognized over an estimated weighted-average amortization period of 1.7 years. During the year ended September 30, 2019, no stock options were exercised or forfeited.

The fair value of stock option grants are estimated on the date of grant using the Black-Scholes option-pricing model. The Company was historically a private company and lacked company-specific historical and implied volatility information. Therefore, it estimates its expected stock volatility based on the historical volatility of a publicly traded set of peer companies. Additionally, due to an insufficient history with respect to stock option activity and post-vesting cancellations, the expected term assumption for employee grants is based on a permitted simplified method, which is based on the vesting period and contractual term for each tranche of awards. The mid-point between the weighted-average vesting term and the expiration date is used as the expected term under this method. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect for time periods approximately equal to the expected term of the award. Expected dividend yield is zero based on the fact that the Company has never paid cash dividends and does not expect to pay any cash dividends in the foreseeable future.

The weighted average grant date fair value of options granted during the year ended September 30, 2019 was $2.31.  

Key assumptions used to estimate the fair value of the stock options granted during the year ended September 30, 2019 included:

 

 

Restricted Stock

A summary of the changes in the outstanding restricted stock during the year ended September 30, 2019 is as follows:

 

 

During the year ended September 30, 2019, Private NeuBase sold restricted stock to consultants for services to be provided to Private NeuBase and entered into related restricted stock agreements. The gross proceeds from the sale of the restricted stock was $1,474. The restricted stock was scheduled to vest over a period of 3 years, subject to accelerated vesting upon certain performance targets. Upon closing of the Ohr Acquisition, Private NeuBase accelerated the vesting of the restricted stock issued to the consultants.

The Company recorded stock-based compensation expense in the following expense categories of its consolidated statements of operations for the year ended September 30, 2019 and for the period from August 28, 2018 (inception) to September 30, 2018: