NOTE 5 - STOCKHOLDERS’ EQUITY

Preferred Stock

Our amended and restated certificate of incorporation authorizes the issuance of up to 10,000,000 shares of preferred stock, $0.001 par value, with rights senior to those of our common stock, issuable in one or more series. Upon issuance, we can determine the rights, preferences, privileges and restrictions thereof. These rights, preferences and privileges could include dividend rights, conversion rights, voting rights, terms of redemption, liquidation preferences, sinking fund terms and the number of shares constituting any series or the designation of such series, any or all of which may be greater than the rights of common stock.

Common Stock

Our amended and restated certificate of incorporation authorizes the issuance of up to 150,000,000 shares of $0.001 par value common stock.

In December 2014, we filed a shelf registration statement on Form S-3 (the “2015 S-3”), which was declared effective in January 2015. Under the 2015 S-3, the Company may sell up to a total of $250 million of its securities. In connection with the 2015 S-3, we amended our 2013 At-the-Market Issuance Sales Agreement with MLV & Co. LLC (the “2015 ATM”) such that we may issue and sell additional shares of our common stock, having an aggregate offering price of up to $75.0 million, from time to time through MLV & Co. LLC (“MLV”), acting as the sales agent. Under the 2015 ATM, we would pay MLV a commission rate of up to 3.0% of the gross proceeds from the sale of any shares of common stock sold through MLV.

During the first quarter ended March 31, 2015, we sold a total of 2,195,016 shares of common stock under the 2015 ATM for aggregate total gross proceeds of approximately $34.8 million at an average selling price of $15.87 per share, resulting in net proceeds of approximately $34.2 million after deducting commissions and other transactions costs.

From April 1, 2015 through May 8, 2015, we sold an aggregate of 518,076 shares of common stock pursuant to the 2015 ATM for total gross proceeds of approximately $8.5 million at an average selling price of $16.38 per share, resulting in net proceeds of approximately $8.0 million after deducting commissions and other transactions costs.

We currently have two shelf registration statements on Form S-3 filed and declared effective by the SEC (File No. 333-189015 and File No. 333-201339). After deducting shares already sold, approximately $273 million of common stock remains available for sale under these shelf registration statements. We may offer the securities under our shelf registration statements from time to time in response to market conditions or other circumstances if we believe such a plan of financing is in the best interests of our stockholders. We believe that these shelf registration statements provide us with the flexibility to raise additional capital to finance our operations as needed.

Equity Incentive Plans

Shares available for the issuance of stock options or other stock-based awards under our stock option and incentive plans were 115,166 shares at March 31, 2015.

Stock Options

The following table summarizes stock option activity for the three months ended March 31, 2015:

	Number of shares		Weighted- average exercise price		Weighted- average Contractual Term		Aggregate Intrinsic Value
					(in years)
Outstanding at December 31, 2014		194	$	971.70		3.50	$	--
Granted		--		--
Exercised		--		--
Forfeited		--		--
Expired		(42)		2,811.53
Outstanding at March 31, 2015		152	$	463.32		4.22	$	--

Exercisable at March 31, 2015		152	$	463.32		4.22	$	--

As of March 31, 2015, there are no unvested option awards and no unrecognized compensation cost related to option awards.

Restricted Stock

Certain employees, directors and consultants have been awarded restricted stock. The restricted stock vesting consists of milestone and time-based vesting. The following table summarizes restricted share activity for the three months ended March 31, 2015:

	Number of Shares		Weighted Average Grant Date Fair Value
Outstanding at December 31, 2014		6,400,001	$	5.86
Granted		12,000		14.59
Vested		(380,001)		4.23
Forfeited		(1,166)		10.53
Outstanding at March 31, 2015		6,030,834	$	5.98

Total expense associated with restricted stock grants was $5,357,028 during the three months ended March 31, 2015. As of March 31, 2015, there was approximately $13.6 million of total unrecognized compensation cost related to unvested time-based restricted stock, which is expected to be recognized over a weighted-average period of 2 years. This amount does not include, as of March 31, 2015, 134,302 shares of restricted stock outstanding which are milestone-based and vest upon certain corporate milestones; and 1,965,250 shares of restricted stock outstanding issued to non-employees. Milestone-based non-cash compensation expense will be measured and recorded if and when a milestone occurs. The expense for non-employee shares is determined at the “measurement date.” The expense is recognized over the vesting period of the award. Until the measurement date is reached, the total amount of compensation expense remains uncertain. We record compensation expense based on the fair value of the award at the reporting date.

Warrants

The following table summarizes warrant activity for the three months ended March 31, 2015:

	Warrants		Weighted- average exercise price		Aggregate Intrinsic Value
Outstanding at December 31, 2014		4,148,228	$	0.94	$	61,792,184
Issued		--		--
Exercised		(177,448)		2.34
Expired		(11,364)		2.25
Outstanding at March 31, 2015		3,959,416	$	0.88	$	57,817,178

Stock-Based Compensation

The fair value of stock options granted is estimated at the date of grant using the Black-Scholes pricing model. The expected term of options granted is derived from historical data and the expected vesting period. Expected volatility is based on the historical volatility of our common stock. The risk-free interest rate is based on the U.S. Treasury yield for a period consistent with the expected term of the option in effect at the time of the grant. We have assumed no expected dividend yield, as dividends have never been paid to stock or option holders and will not be paid for the foreseeable future. We did not grant any stock options during the three months ended March 31, 2015 and 2014.

The following table summarizes stock-based compensation expense information about stock options and restricted stock for the three months ended March 31, 2015:

	Three months ended March 31, 2015		Three months ended March 31, 2014
Stock-based compensation expense associated with restricted stock	$	5,357,028	$	4,231,438
Stock-based compensation expense associated with option grants		--		--
	$	5,357,028	$	4,231,438