Note 10.      Stockholders’ Equity

At March 31, 2016, there were 4,886,764 stock warrants and 5,052,409 stock options outstanding, all totaling 30,768,130 of total stock and stock equivalents outstanding at March 31, 2016. At December 31, 2015, there were 4,886,764 stock warrants and 5,236,909 stock options outstanding, totaling 28,752,630 of total stock and stock equivalents outstanding at December 31, 2015.

Equity Purchase Agreement

On September 4, 2015, we entered into an equity purchase agreement with Aspire Capital Fund, LLC (“Aspire Capital”), which provides that Aspire Capital is committed to purchase up to an aggregate of $10.0 million of shares of our common stock over a two-year term, subject to our election to sell any such shares, and subject to the Nasdaq Listing Rule 5635(d) limitation. Nasdaq Listing Rule 5635(d) (“the Nasdaq 20% Rule”), requires shareholder approval of a transaction other than a public offering involving the sale, issuance, or potential issuance by a company of common stock (or securities convertible into or exercisable for common stock) equal to 20% or more of the company’s outstanding shares of common stock, or 20% or more of the voting power outstanding before the issuance for less than the greater of book or market value of the stock. Under this 20% Nasdaq Rule, we had a total of approximately 3.6 million common shares available for sale or transfer to Aspire Capital under this equity purchase agreement at September 4, 2015.

Under the agreement, we have the right to sell shares, subject to certain volume limitations and a minimum floor price, to Aspire Capital as of January 8, 2016, the date that the Securities and Exchange Commission (the “SEC”) declared the Form S-1 registration statement registering the resale of the Company’s common stock by Aspire Capital to be effective. On any trading day selected by the Company, the Company will have the right, in its sole discretion, to present Aspire Capital with a purchase notice directing Aspire Capital (as principal) to purchase up to 100,000 shares of the Company’s common stock per business day (in a purchase amount up to $250,000 on each such business day) at a price equal to the lesser of:

In addition, on any date on which we submit a purchase notice to Aspire Capital in an amount equal to 100,000 shares, the Company also has the right, in its sole discretion, to present Aspire Capital with a volume-weighted average price purchase notice (each, a “VWAP Purchase Notice”) directing Aspire Capital to purchase an amount of stock equal to up to 30% of the aggregate shares of the Company’s common stock traded on its principal market on the next trading day (the “VWAP Purchase Date”), subject to a maximum number of shares as the Company may determine. The purchase price per share pursuant to such VWAP Purchase Notice is generally 95% of the volume-weighted average price for the Company’s common stock traded on its principal market on the VWAP Purchase Date.

As part of the agreement, Aspire Capital received 300,000 additional shares as compensation for its commitment, valued at approximately $276,000 or $0.92 per common share.

For the three months ended March 31, 2016 we sold 2.2 million common shares for total gross proceeds of approximately $1.4 million through the equity line financing arrangement with Aspire Capital that we have in place. See Note 13 – Subsequent Events for subsequent sales of stock to Aspire Capital after March 31, 2016.

ATM Offering

On June 11, 2015, the Company entered into an at-the-market issuance (“ATM”) sales agreement with MLV & Co. LLC ("MLV"), pursuant to which the Company may issue and sell shares of its common stock from time to time through MLV as the Company's sales agent. On September 1, 2015, MLV was acquired by FBR & Co. The issuance and sale of shares by the Company under the sales agreement are registered shares under the Company's shelf registration statement on Form S-3, as filed with the Securities and Exchange Commission on June 11, 2015 and declared effective by the Securities and Exchange Commission. The Company has registered the sale of up to $5.8 million of common stock under the ATM sales agreement. There have been 246,083 shares sold for total gross proceeds of approximately $282,000 through the ATM for the twelve month period ended December 31, 2015. There were no ATM sales for the three months ended March 31, 2016.

Outstanding Warrants

Stock-based Compensation – Stock Options and Restricted Stock

Stock Plan

On March 25, 2015, the Compensation Committee and Board of Directors approved the 2015 Equity Incentive Plan (the “Plan”) to authorize grants of (a) Incentive Stock Options, (b) Non-qualified Stock Options, (c) Stock Appreciation Rights, (d) Restricted Awards, (e) Performance Share Awards, and (f) Performance Compensation Awards to the employees, consultants, and directors of the Company. The Plan authorizes a total of 3,000,000 shares to be available for grant under the Plan. The Plan became effective upon ratification by the shareholders of the Company at the shareholders’ annual meeting on July 14, 2015. Other provisions are as follows:

Total stock options outstanding at March 31, 2016 and December 31, 2015, were 5,052,409 and 5,236,909 of which 3,257,523 and 3,442,023 of these options were vested at March 31, 2016 and December 31, 2015, respectively. Stock-based compensation was approximately $0.2 and $0.1 million for the three months ended March 31, 2016 and 2015, respectively.

2015 Short-Term Non-Qualified Option Grants

On April 8, 2015, the Compensation Committee and the Board of Directors granted short term non-qualified stock options totaling 463,192 and 148,845 stock options under the 2006 Stock Plan and the 2015 Equity Incentive Plan, respectively, to employees and consultants of the Company. On April 9, 2015, the Compensation Committee and the Board of Directors granted an additional 47,017 and 3,968 stock options under the 2006 Stock Plan and the 2015 Equity Incentive Plan, respectively, all with a strike price of $1.26. These stock options vested immediately but the grants under the 2015 Equity Incentive Plan became exercisable upon ratification of the Plan at the annual meeting of shareholders, which took place on July 14, 2015.

On August 12, 2015, the Compensation Committee and the Board of Directors granted short term non-qualified stock options totaling 135,880 stock options under the 2015 Equity Incentive Plan to employees and consultants of the Company, all with a strike price of $1.26. These stock options vested immediately.

On November 20, 2015, the Compensation Committee and the Board of Directors granted short term non-qualified stock options totaling 1,129,135 stock options under the 2015 Equity Incentive Plan to employees and consultants of the Company, all with a strike price of $0.92. These stock options vested immediately.

Also granted under the 2006 Stock Plan were 2,981, 1,775, 1,310, 8,368, 14,805, 18,305, and 22,390 non-qualified stock options in 2015 on April 30, May 31, June 30, and December 31, 2015 and in 2016 on January 31, February 29, and March 31, 2016, respectively, as equity compensation in lieu of cash with strike prices ranging from $0.56 to $1.25. Also granted under the 2015 Equity Incentive Plan were 1,812, 1,536, 1,803, 8,255 and 9,752 non-qualified stock options on July 31, August 31, September 30, 2015, October 31, 2015, and November 30, 2015, respectively, as equity compensation in lieu of cash with strike prices ranging from $0.83 to $1.25.

These stock options have an expected life of 1.5 - 5 years, and a contractual term of 3 - 10 years, a fair value of between $0.10 and $0.86 per stock option, a risk free rate ranging between 0.42% to 1.76%, and volatility ranging between 76% to 89%, as measured on the grant date. The expected option term was calculated using the simplified method as we do not have sufficient historical option data to provide a better estimate of the expected option term. Under this method, the weighted-average expected life is presumed to be the average of the vesting term and the contractual term of the option, which results in a reduction of the estimated option value and consequently the stock option expense. The risk free rate was based on the US Treasury Yield Curve for the expected life of the options on the grant date. Expected dividends are estimated at $0.0, as we have never issued dividends and we have no current plans to issue dividends in the future.

2015 Long-Term Incentive Option Grants

Employees and Consultants Option Grants

On April 8, 2015, August 12, 2015, and November 20, 2015, the Compensation Committee and the Board of Directors granted long term incentive stock options totaling 550,972, 79,588, and 661,222 respectively, under the 2015 Equity Incentive Plan, the (“Plan”) to employees and consultants of the Company. These stock options vest 1/3 on each annual anniversary date over three years. These stock options have a strike price ranging from $0.92 to $1.26, and the stock options have a fair value ranging from $0.67 to $0.91, based on a risk free rate of between 1.55% and 1.87%, volatility between 86% and 87%, and an expected life of six years, as measured on the grant date. The expected life is calculated using the simplified method as we do not have sufficient historical option data to provide a better estimate of the expected option term. These options have a 10 year contractual term. The risk free rate was based on the US Treasury Yield Curve for the expected life of the options on the grant date. Expected dividends are estimated at $0.0, as we have never issued dividends and we have no current plans to issue dividends in the future. Grants to our consultants were re-measured as of March 31, 2016 and 2015, and the fair value of each option was between $0.34 and $0.36 on the measurement date. This re-measured stock-based compensation for options issued to consultants was not significant. We estimated future pre-vest forfeitures to be 1.5%, based on historical information.

Director Option Grants

On April 8, 2015, August 12, 2015, and November 20, 2015, the Compensation Committee and the Board of Directors granted 112,996, 23,024, and 97,988 respectively, of long term non-qualified stock options under the 2015 Equity Incentive Plan to the Board of Directors of the Company. These stock options fully vest on the first annual anniversary date of the grant. These stock options have a strike price between $0.92 and $1.26, and the stock options have a fair value of between $0.65 to $0.88, based on a risk free rate between 1.46% and 1.79%, volatility between 86% and 87%, and an expected life of 5.5 years. The expected life is calculated using the simplified method as we do not have any history to provide a better estimate of the expected option term. These options have a 10 year contractual term. The risk free rate was based on the US Treasury Yield Curve for the expected life of the options on the grant date. Expected dividends are estimated at $0.0, as we have never issued dividends and we have no current plans to issue dividends in the future.

Stock option transactions to the employees, directors and consultants are summarized as follows for the three months ended March 31, 2016:

Stock option transactions to the employees, directors and consultants are summarized as follows for the year ended December 31, 2015:

A summary of the status of the Company’s non-vested shares as of March 31, 2016 and December 31, 2015, and changes during the three months ended March 31, 2016 and the year ended December 31, 2015, is presented below:

As of March 31, 2016, there was approximately $1 million of total unrecognized compensation cost related to non-vested share-based compensation arrangements granted under the plans. That cost is expected to be recognized over a weighted-average period of 1.96 years.  There was no intrinsic value for the stock options outstanding at March 31, 2016 and December 31, 2015.

The above tables include options issued and outstanding as of March 31, 2016 and December 31, 2015, as follows:

The following table provides certain information with respect to the above-referenced stock options that are outstanding and exercisable at March 31, 2016:

The following table provides certain information with respect to the above-referenced stock options that are outstanding and exercisable at December 31, 2015:

We use the historical volatility of our stock price over the number of years that matches the expected life of our stock option grants or we use the historical volatility of our stock price since January 5, 2006, the date we announced that we were becoming a public company, to estimate the future volatility of our stock. At this time we do not believe that there is a better objective method to predict the future volatility of our stock for options with an expected term that is greater than our stock trading history. Prior to January 1, 2015, we estimated the life of our option awards based on the full contractual term of the option grant. To date we have had very few exercises of our option grants, and those stock option exercises had occurred just before the contractual expiration dates of the option awards. Since the strike price of most of our outstanding awards is greater than the price of our stock, generally awards have expired at the end of the contractual term. For options granted after January 1, 2015, we have applied the simplified method to estimate the expected term of our option grants as it is more likely that these options may be exercised prior to the end of the term. We estimate the effect of future forfeitures of our option grants based on an analysis of historical forfeitures of unvested grants, as we have no better objective basis for that estimate. The expense that we have recognized related to our grants includes the estimate for future pre-vest forfeitures. We will adjust the actual expense recognized due to future pre-vest forfeitures as they occur. We have estimated that 1.5% of our option grants will be forfeited prior to vesting.

Weighted average assumptions used in the Black Scholes option-pricing model for the three months ended March 31, 2016 and the year ended December 31, 2015, were as follows:

Stock-based compensation expense includes the expense related to (1) Grants of stock options, (2) grants of restricted stock, (3) Stock issued as consideration for some of the services provided by our directors and strategic advisory council members, and (4) stock issued in lieu of cash to pay bonuses to our employees and contractors. Grants of stock options and restricted stock are awarded to our employees, directors, consultants, and board members and we recognize the fair value of these awards ratably as they are earned. The expense related to payments in stock for services is recognized as the services are provided.

Stock-based compensation expense is recorded under the financial statement captions cost of services provided, general and administrative expenses and research and development expenses in the accompanying condensed consolidated statements of operations. For the three months ended March 31, 2016 and 2015, we recognized stock-based compensation of approximately $0.2 million and $0.1 million, respectively. Related income tax benefits were not recognized, as we incurred a tax loss for both periods.