(7) Common Stock

As of December 31, 2016, the Company had 200,000,000 authorized shares of common stock, $0.001 par value, of which 75,862,946 shares were issued and outstanding.

Private Placement / PIPE Warrants

In May 2016, the Company entered into a securities purchase agreement with a select group of qualified institutional buyers, institutional accredited investors and accredited investors pursuant to which the Company sold 17,642,482 units, at a price of $0.965 per unit, for gross proceeds of approximately $17.0 million. Each unit consisted of one share of the Company’s common stock and a warrant to purchase one share of the Company’s common stock (the “PIPE Warrants”). The PIPE Warrants have an exercise price of $1.00 per share and are exercisable for a period of five years from the date of issuance. Certain of the Company’s directors and executive officers purchased an aggregate of 544,039 units in this offering at the same price as the other investors. The net offering proceeds to the Company were approximately $15.4 million after deducting placement agent fees and other offering expenses payable by the Company.

The PIPE Warrants contain a provision giving the warrant holder the option to receive cash, equal to the fair value of the remaining unexercised portion of the warrant, as cash settlement in the event that there is a fundamental transaction (contractually defined to include various merger, acquisition or stock transfer activities). Due to this provision, ASC 480, Distinguishing Liabilities from Equity requires that these warrants be classified as a liability and not as equity. Accordingly, the Company recorded a warrant liability in the amount of approximately $9.3 million upon issuance of the PIPE Warrants. The fair value of these warrants has been determined using the Black-Scholes pricing model, and the changes in the fair value at the time of each reporting date are recorded in the Statements of Operations. During the year ended December 31, 2016, as a result of the fair value adjustment of the warrant liability, the Company recorded a decrease in the fair value of the warrant liability of approximately $4.8 million in the Statements of Operations. As of December 31, 2016, none of the PIPE Warrants have been exercised.

The key assumptions used to value the PIPE Warrants were as follows:

	Original Issuance		December 31, 2016
Expected price volatility	76.25%			78.18%
Expected term (in years)		5.00		4.50
Risk-free interest rates		1.22%		1.93%
Stock price	$	0.89	$	0.54
Dividend yield		—		—

ATM Sales Agreement

In February 2015, the Company entered into an at-the-market issuance sales agreement (the “Sales Agreement”) with FBR & Co. (formerly MLV & Co. LLC) (“FBR”), pursuant to which the Company could issue and sell shares of its common stock from time to time up to an aggregate amount of $17.9 million, at the Company’s option, through FBR as its sales agent. Sales of common stock through FBR may be made by any method that is deemed an “at-the-market” offering as defined in Rule 415 promulgated under the Securities Act of 1933, as amended. Subject to the terms and conditions of the Sales Agreement, FBR will use commercially reasonable efforts to sell the common stock based upon the Company’s instructions (including any price, time or size limits or other customary parameters or conditions the Company may impose). The Company is not obligated to make any sales of its common stock under the Sales Agreement. Any shares sold will be sold pursuant to an effective shelf registration statement on Form S-3. The Company will pay FBR a commission of up to 3% of the gross proceeds. The Sales Agreement may be terminated by the Company at any time.

On May 7, 2015, the Company filed a shelf registration statement on Form S-3 with the SEC, which covers the offering, issuance and sale by the Company of up to $100.0 million of its common stock, preferred stock, debt securities, warrants and/or units (the “2015 Shelf”). The 2015 Shelf was filed to replace the Company’s existing $250.0 million shelf registration statement (the “2012 Shelf”). On May 7, 2015, the Company also amended its Sales Agreement with FBR to provide for the offering, issuance and sale by the Company of up to $15.0 million of its common stock under the 2015 Shelf, which replaced the Company’s existing $17.9 million offering that expired along with the expired 2012 Shelf. As of December 31, 2016, the Company has sold approximately 5.9 million shares pursuant to the Sales Agreement, as amended, resulting in proceeds of approximately $10.2 million, net of commissions and issuance costs. No shares have been sold during the year ended December 31, 2016.

Approximately $9.1 million remains available for sale under the Sales Agreement.