A cashless warrant issued in connection with a marketing and consulting agreement is classified as a derivative liability as opposed to equity. This cashless warrant is a non-cash liability, and the Company is not required to expend any cash to settle this liability. The fair value of this cashless warrant is recorded on the balance sheets at issuance. The cashless warrant was marked to fair value at each financial reporting period, with changes in the fair value recorded as a gain or loss in the consolidated statements of operations. The fair value of the cashless warrants is determined using the Black-Scholes option pricing model, which requires the use of significant judgment and estimates for the inputs used in the model. The following reflects the weighted-average assumptions for each of the periods indicated:

The dividend yield assumption of zero is based upon the fact the Company has never paid cash dividends and presently has no intention of paying cash dividends.  The risk-free interest rate used for each grant is equal to the U.S. Treasury rates in effect at the time of the grant for instruments with a similar expected life. The expected lives are based on the remaining contractual lives of the related warrants at the valuation date. The Company’s computation of expected volatility is based on the historical daily volatility of its publicly traded stock.

The derivative liability level within the fair value hierarchy is a Level 3 - Significant Unobservable Input.

The change in the fair value for Level 3 derivative liability for the year ended April 30, 2015, is as follows: