Warrant Activity

Warrant detail for the three months ended September 30, 2019 is reflected below:

Warrant detail for the three months ended September 30, 2018 is reflected below:

Stock-based Compensation 

On November 26, 2014, the board of directors approved the 2014 Equity Incentive Plan (the “2014 Plan”), which was approved by the Company’s stockholders on February 17, 2015. The 2014 Plan offers selected employees, directors, and consultants the opportunity to acquire our common stock, and serves to encourage such persons to remain employed by us and to attract new employees. The 2014 Plan allows for the award of stock and options, up to 1,000,000 shares of our common stock.  

Activity in stock options during the three months ended September 30, 2019 and related balances outstanding as of that date are reflected below:

Activity in stock options during the three months ended September 30, 2018 and related balances outstanding as of that date are reflected below:

Stock-based compensation expense recognized in the condensed consolidated statements of operations for the three months ended September 30, 2019 and 2018, includes compensation expense for stock-based options and awards granted based on the grant date fair value. For options and awards granted, expenses are amortized under the straight-line method over the expected vesting period. Stock-based compensation expense recognized in the condensed consolidated statements of operations has been reduced for estimated forfeitures of options that are subject to vesting. Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates.

At September 30, 2019, the aggregate intrinsic value of exercisable options was $659,000 .

The Company allocated stock-based compensation expense included in the condensed consolidated statements of operations for employee option grants and non-employee option grants as follows:

The Company uses the Black-Scholes valuation model to calculate the fair value of stock options. The fair value of stock options was measured at the grant date using the assumptions (annualized percentages) in the table below:

The remaining amount of unrecognized stock-based compensation expense at September 30, 2019 relating to outstanding stock options, is approximately $1,163,000, which is expected to be recognized over the weighted-average period of 1.71 years.