5.    Stockholders’ Equity

January 2013 Private Placement

In January 2013, the Company entered into a securities purchase agreement for the private placement of shares of the Company’s common stock and warrants to purchase shares of the Company’s common stock, at a purchase price of $1.20 per unit (the “January 2013 Financing Transaction”). Each unit consisted of one share of common stock and a warrant to purchase one-half share of common stock.

In the January 2013 Financing Transaction, the Company sold to the investors 9,201,684 shares of common stock, together with warrants to purchase 4,600,842 shares of common stock, for aggregate gross proceeds of $11,042,021, before commissions and offering expenses. Non-employee directors of the Company invested a total of $402,000 in the January 2013 Financing Transaction. Each warrant is exercisable for five years from the date of issuance and has an exercise price of $1.75 per share, subject to adjustment from time to time for stock splits or combinations, stock dividends, stock distributions, recapitalizations and other similar transactions. In the event the Company issues shares of its common stock or common stock equivalents in a subsequent financing transaction at a price below the then prevailing warrant exercise price, the exercise price of the warrants will be adjusted downward (commonly referred to as a “down round” provision) to the price at which the Company issues the common stock or common stock equivalents.

In addition, the warrants contain a net-cash settlement feature that gives the warrant holder the right to net-cash settlement in the event certain transactions occur. Pursuant to the net-cash settlement provision of the warrants, if such a transaction occurs, the warrant holder will be entitled to receive cash equal to the value calculated under the Black-Scholes valuation model using (i) an expected volatility equal to the greater of 100% and the 100-day volatility obtained from the HVT function on Bloomberg, (ii) an expected term equal to the remaining term of the warrant, and (iii) an interest rate equal to the United States Treasury risk-free rate for the term of the lesser of the remaining term of the warrant or twenty-four months.

The Company’s placement agents earned commissions of $1,104,202 and the Company incurred other transaction costs of $133,024 related to the January 2013 Financing Transaction.

In connection with the January 2013 Financing Transaction, the Company entered into a registration rights agreement with the investors pursuant to which the Company filed a registration statement with the SEC covering the resale of the shares of common stock and the shares of common stock underlying the warrants issued in the financing. The Company must bear the costs, including legal and accounting fees, associated with the registration of those shares. If the Company fails to continuously maintain the effectiveness of the registration statement (with certain permitted exceptions), the Company will incur certain damages to the investors, up to a maximum amount of 12% of the investors’ investments in the January 2013 Financing Transaction, or approximately $1,300,000.

Common Stock Warrants Requiring Liability Accounting

Under guidance in FASB ASC 815-40, “Contracts in Entity's Own Equity,” the net-cash settlement and down round provisions contained in the warrants issued in the January 2013 Financing Transaction require derivative liability accounting treatment for the warrants. Likewise, under ASC 815-40, the down round provision contained in the warrants issued in the July 2012 Financing Transaction also requires derivative liability accounting treatment for the warrants. As of September 30, 2013 and December 31, 2012, the aggregate fair value of these warrants was $4,106,224 and $2,128,302, respectively. The fair value of these warrants was calculated using the Monte Carlo simulation valuation method.

Assumptions used in calculating the fair value of these warrants are noted below (including assumptions used in calculating the transaction date fair value for the warrants issued in the January 2013 Financing Transaction):

In addition to the assumptions above, the Company also takes into consideration whether the Company would participate in another equity financing and, if so, what the offering price would be in such a financing at that time.

The change in the fair value of the warrants accounted for as derivative liabilities is reflected below:

The Company will continue to adjust the derivative liability for changes in fair value until the earlier of the expiration or exercise of the warrants, at which time the liability will be reclassified to stockholders' equity.

Stock Options

In June 2013, the stockholders of the Company approved the creation of a new share-based incentive plan (the “2013 Plan”). Following stockholder approval of the 2013 Plan, no new grants under the Company’s prior stock plans were made. A total of 1,250,000 shares of the Company’s common stock are reserved for issuance under the 2013 Plan, of which awards as to 382,500 shares had been made as of September 30, 2013. Thus, 867,500 shares remained available for award grants as of September 30, 2013 under the 2013 Plan. On November 5, 2013, awards as to 567,000 shares were granted to employees under the 2013 Plan.

Activity under all of the Company’s equity compensation plans during the nine months ended September 30, 2013 is summarized below:

The estimated grant date fair values of options granted during the nine months ended September 30, 2013 were calculated using the Black-Scholes valuation model, based on the following assumptions:

The Company records share-based compensation expense on a straight-line basis over the related vesting period. For the periods indicated below, employee share-based compensation expense related to options was:

As of September 30, 2013, there was unrecognized compensation expense of $1,117,909 related to outstanding stock options which is expected to be recognized over a weighted average period of approximately 1.5 years.

Warrants

Warrants have generally been issued for terms of up to five years. Common stock warrant activity for the nine months ended September 30, 2013 was as follows:

In August 2013, warrants were issued to a service provider to purchase 43,000 shares of the Company’s common stock at $1.75 per share. The fair value of these warrants of $14,805, which was calculated using the Black-Scholes valuation model, was recorded as share-based compensation expense. Assumptions used in calculating the fair value of these warrants included a dividend yield of 0%, expected volatility of 46.49%, a risk free interest rate of 1.38%, and an expected life of 5 years.

During the nine months ended September 30, 2013, certain warrants were exercised on a net settlement basis which resulted in the Company withholding 61,346 shares out of the common stock warrants exercised.