Equity	6 Months Ended
Jun. 30, 2013
Equity
Equity	Note 2 — Equity Common Stock Purchase Agreement On January 15, 2013, we entered into a Common Stock Purchase Agreement (the *“Purchase Agreement”) with Aspire Capital Fund, LLC (“Aspire Capital”), which provides that, upon the terms and subject to the conditions and limitations set forth therein, Aspire Capital is committed to purchase up to an aggregate of $25.0 million in shares of our common stock (the “Purchase Shares”) over a two-year period at purchase prices determined in accordance with the Purchase Agreement. Pursuant to the terms of the Purchase Agreement, we have filed and maintain a registration statement on Form S-1 with the SEC under which we have registered 3,000,000 shares of our common stock for resale by Aspire Capital. In consideration for entering into the Purchase Agreement, concurrently with the execution of the Purchase Agreement, we issued to Aspire Capital 80,257 shares of our common stock as a commitment fee (the “Commitment Shares”). The Purchase Agreement provides that we may not issue and sell more than 1,856,616 shares, or 19.99% of the Company’s outstanding shares as of January 15, 2013. As of June 30, 2013, we have sold 146,886 shares of common stock to Aspire Capital pursuant to the Purchase Agreement. Including the Commitment Shares, an aggregate of 227,143 shares of common stock have been issued to Aspire Capital pursuant to the Purchase Agreement. The Purchase Agreement contains customary representations, warranties, covenants, closing conditions and indemnification and termination provisions by, among and for the benefit of the parties. The Purchase Agreement may be terminated by us at any time, at our discretion, without any cost or penalty to us. Aspire Capital has covenanted not to cause or engage in any manner whatsoever, any direct or indirect short selling or hedging of our shares. We did not pay Aspire Capital any expense reimbursement in connection with the transaction. There are no limitations on use of proceeds, financial or business covenants, restrictions on future fundings, rights of first refusal, participation rights, penalties or liquidated damages in the Purchase Agreement. Public Offering* On April 16, 2013 we sold 2,875,000 shares of common stock in a public offering at $5.25 per share including 375,000 shares of common stock pursuant to the exercise of the over-allotment option by our underwriters. Proceeds in the public offering and exercise of the over-allotment option, net of transaction costs were $14,036 in the aggregate. Stock-Based Compensation The Company recognizes all share-based payments, including grants of stock options and compensatory employee stock purchase plans, in the income statement as an operating expense, based on their fair value over the requisite service period. We recorded $483 and $174 of related compensation expense to selling, general and administrative expense and research and development expense, respectively, for the three months ended June 30, 2013, as compared to $196 and $107, respectively, of related compensation expense for the three months ended June 30, 2012.We recorded $603 and $286 of related compensation expense to selling, general and administrative expense and research and development expense, respectively, for the six months ended June 30, 2013, as compared to $402 and $219, respectively, of related compensation expense for the six months ended June 30, 2012. As of June 30, 2013, a total of $5,106 of unrecognized compensation costs related to non-vested stock option awards was outstanding and is expected to be recognized within the next 3.8 fiscal years. The Company uses the Black-Scholes option pricing model to determine the weighted average fair value of options. The volatility factor used in the Black-Scholes option pricing model is based on historical stock price fluctuations. The current forfeiture rate is based on a reasonable estimate by management. Expected dividend yield is based upon the Company’s historical and projected dividend activity and the risk free interest rate is based upon US Treasury rates appropriate for the expected term of the options. The expected term is based on estimates regarding projected employee stock option exercise behavior. The Company’s stock options generally vest over four years of service and have a contractual life of 10 years. We have 400,924 shares authorized for grant under our Amended and Restated 2011 Equity Incentive Plan and 195,000 shares authorized for grant under our 2013 Non-Executive Directors’ Equity Incentive Plan. Warrants Warrants to purchase 1,633,253 shares of common stock were outstanding at June 30, 2013 and December 31, 2012.

Note 2 — Equity

Common Stock Purchase Agreement

On January 15, 2013, we entered into a Common Stock Purchase Agreement (the “Purchase Agreement”) with Aspire Capital Fund, LLC (“Aspire Capital”), which provides that, upon the terms and subject to the conditions and limitations set forth therein, Aspire Capital is committed to purchase up to an aggregate of $25.0 million in shares of our common stock (the “Purchase Shares”) over a two-year period at purchase prices determined in accordance with the Purchase Agreement. Pursuant to the terms of the Purchase Agreement, we have filed and maintain a registration statement on Form S-1 with the SEC under which we have registered 3,000,000 shares of our common stock for resale by Aspire Capital.

In consideration for entering into the Purchase Agreement, concurrently with the execution of the Purchase Agreement, we issued to Aspire Capital 80,257 shares of our common stock as a commitment fee (the “Commitment Shares”). The Purchase Agreement provides that we may not issue and sell more than 1,856,616 shares, or 19.99% of the Company’s outstanding shares as of January 15, 2013.

As of June 30, 2013, we have sold 146,886 shares of common stock to Aspire Capital pursuant to the Purchase Agreement. Including the Commitment Shares, an aggregate of 227,143 shares of common stock have been issued to Aspire Capital pursuant to the Purchase Agreement.

The Purchase Agreement contains customary representations, warranties, covenants, closing conditions and indemnification and termination provisions by, among and for the benefit of the parties. The Purchase Agreement may be terminated by us at any time, at our discretion, without any cost or penalty to us. Aspire Capital has covenanted not to cause or engage in any manner whatsoever, any direct or indirect short selling or hedging of our shares. We did not pay Aspire Capital any expense reimbursement in connection with the transaction. There are no limitations on use of proceeds, financial or business covenants, restrictions on future fundings, rights of first refusal, participation rights, penalties or liquidated damages in the Purchase Agreement.

Public Offering

On April 16, 2013 we sold 2,875,000 shares of common stock in a public offering at $5.25 per share including 375,000 shares of common stock pursuant to the exercise of the over-allotment option by our underwriters. Proceeds in the public offering and exercise of the over-allotment option, net of transaction costs were $14,036 in the aggregate.

Stock-Based Compensation

The Company recognizes all share-based payments, including grants of stock options and compensatory employee stock purchase plans, in the income statement as an operating expense, based on their fair value over the requisite service period. We recorded $483 and $174 of related compensation expense to selling, general and administrative expense and research and development expense, respectively, for the three months ended June 30, 2013, as compared to $196 and $107, respectively, of related compensation expense for the three months ended June 30, 2012.We recorded $603 and $286 of related compensation expense to selling, general and administrative expense and research and development expense, respectively, for the six months ended June 30, 2013, as compared to $402 and $219, respectively, of related compensation expense for the six months ended June 30, 2012. As of June 30, 2013, a total of $5,106 of unrecognized compensation costs related to non-vested stock option awards was outstanding and is expected to be recognized within the next 3.8 fiscal years.

The Company uses the Black-Scholes option pricing model to determine the weighted average fair value of options. The volatility factor used in the Black-Scholes option pricing model is based on historical stock price fluctuations. The current forfeiture rate is based on a reasonable estimate by management. Expected dividend yield is based upon the Company’s historical and projected dividend activity and the risk free interest rate is based upon US Treasury rates appropriate for the expected term of the options. The expected term is based on estimates regarding projected employee stock option exercise behavior.

The Company’s stock options generally vest over four years of service and have a contractual life of 10 years. We have 400,924 shares authorized for grant under our Amended and Restated 2011 Equity Incentive Plan and 195,000 shares authorized for grant under our 2013 Non-Executive Directors’ Equity Incentive Plan.

Warrants

Warrants to purchase 1,633,253 shares of common stock were outstanding at June 30, 2013 and December 31, 2012.