Note 11 - Warrants

12 Months Ended

Dec. 31, 2013

Warrants [Abstract]

Warrants [Text Block]

11. WARRANTS

As more fully described in Note 9, the Company completed a series of equity financing transactions in 2013 and 2011 that included the issuance of warrants to purchase 1,341,382 and 2,394,398 shares, respectively, of the Company’s common stock. In connection with the Hercules Credit Agreement and the Horizon & Oxford Credit Agreement the Company entered into in November 2013 and June 2012 as more fully described in Note 7, the Company issued warrants to purchase 194,986 and 11,415 shares, respectively, of the Company’s common stock. During 2013, 2012 and 2011, the Company received gross proceeds of approximately $0.2 million, $10.2 million and $0.4 million, respectively, from the exercise of warrants to purchase 15,833, 847,715 and 34,859 shares of common stock, respectively.

Following is a summary of all warrant activity for the three years ended December 31, 2012:

Warrants	Number of Warrants Issued			Weighted Average Exercise Price
Warrants outstanding at January 1, 2011		224,239		$	23.58
Warrants issued in connection with 2011 equity transactions		2,394,398			13.28
Warrants exercised for common stock warrants in 2011		(34,859	)		12.29
Warrants outstanding at December 31, 2011		2,583,778		$	14,18
Warrants issued in connection with the Oxford & Horizon Credit Agreement as more fully described in Note 7		11,415		$	13.14
Warrants exercised for common stock in 2012		(847,715	)		12.11
Warrants outstanding at December 31, 2012		1,747,478			15.17
Warrants issued in connection with 2013 equity transactions		1,341,382			5.31
Warrants issued in connection with the Hercules Credit Agreement as more fully described in Note 7		194,986			3.59
Warrants exercised for common stock in 2013		(15,833	)		14.63
		3,268,013		$	10.43
Aggregate intrinsic value of outstanding warrants at December 31, 2013	$	58,496
Weighted average remaining contractual terms (years)		3.56

Common Stock Warrant Liability

In September 2009, the Company closed a registered direct offering with a select group of institutional investors that raised gross proceeds of $7.1 million and net proceeds of $6.3 million. In connection with this registered direct offering, the Company issued 484,478 shares of its common stock and warrants to purchase 224,239 shares of common stock. The warrants have an exercise price of $23.58 per share and are exercisable at any time on or after the six month anniversary of the date of issuance and on or prior to 66 months after the date of issuance. Under the terms of the warrants, upon certain transactions, including a merger, tender offer or sale of all or substantially all of the assets of the Company, each warrant holder may elect to receive a cash payment in exchange for the warrant, in an amount determined by application of the Black-Scholes option valuation model. Accordingly, pursuant to ASC 815.40, Derivative Instruments and Hedging - Contracts in Entity’s Own Equity, the warrants are recorded as a liability and then marked to market each period through the Statement of Operations in other income or expense. At the end of each subsequent quarter, the Company will revalue the fair value of the warrants and the change in fair value will be recorded as a change to the warrant liability and the difference will be recorded through the Statement of Operations in other income or expense.

As more fully described in Note 9, concurrent with the closing of the Common Stock Offering, the investors in this offering agreed to waive their rights to exercise the Waived Warrants to purchase 1,398,816 shares of common stock of the Company until the Company has obtained stockholders’ approval of increasing the number of its authorized shares of common stock in conjunction with the proposed reverse stock split of its outstanding shares of common stock. In accordance with ASC 815-40, Derivative Instruments and Hedging - Contracts in Entity’s Own Equity, the Waived Warrants were required to be classified as liabilities immediately after the closing of the Common Stock Offering on June 3, 2013 because there were an insufficient number of common shares authorized to permit the full exercise of the Waived Warrants if they were exercised.  Therefore, the Company had reclassified the fair value of the Waived Warrants totaling approximately $9.1 million from equity to a liability as of June 3, 2013.  The Waived Warrants were required to be recorded at fair value at each balance sheet date with changes in fair value recorded in earnings until such time as there are a sufficient number of common shares authorized to permit the full exercise of the warrants.   In connection with the Reverse Stock Split, these warrants were valued as of October 28, 2013 and the Company reclassified the fair value of the Waived Warrants totaling approximately $5.3 million from a liability to equity.

As of December 31, 2013 and 2012, the Company recorded a common stock warrant liability of $3,026 and $4.3 million respectively. The fair value of the warrants associated with the September 2009 registered direct offering at December 31, 2013, 2012 and 2011 was calculated using the Black-Scholes option-pricing model with the following assumptions:

	December 31,
	2013			2012			2011
Risk-free interest rate		0.13	%		0.73	%		0.83	%
Expected volatility		64.74	%		92.02	%		75.17	%
Expected life (in years)		1.25			1.13			1.6
Expected forfeiture rate		0.0	%		0.0	%		0.0	%
Expected dividend yield		0.00	%		0.00	%		0.00	%

See Note 9 for the assumptions used at June 3, 2013 and October 28, 2013 for the Black-Scholes option-pricing model calculation for the Waived Warrants associated with the Common Stock Offering on the dates they were waived and when there became a sufficient number of common shares authorized to permit their full exercise.

As a result of this change in the warrant liability in 2013, which included the change in the warrant liability associated with the Waived Warrants as discussed above, the Company recorded a non-cash benefit of $8.1 million during 2013. The change in the warrant liability during 2012 and 2011 resulted in a non-cash loss of $4.1 million in 2012 and a non-cash benefit of $0.1 million in 2011. The following is a summary of the changes in the common stock warrant liability for 2013, 2012 and 2011:

Beginning balance, January 1, 2011	$	248,131
Benefit from the adjustment for the change in fair value included in net loss for 2010		(81,733	)
Balance at December 31, 2011		166,398
Benefit from the adjustment for the change in fair value included in net loss for 2011		4,117,534
Balance at December 31, 2012		4,283,932
Fair value of warrants classified as liability (see Note 9)		9,110,302
Fair value of warrants classified as equity (see Note 9)		(5,300,572	)
Gain from the adjustment for the change in fair value included in net loss		(8,090,636	)
Ending balance, December 31, 2013	$	3,026