Stockholders' Equity | Note Common stock In May 2008, the Board of Directors of the Company approved the 2008 Equity Incentive Plan (the “2008 Plan”). The 2008 Plan authorized the issuance of up to 1,521,584 common shares for awards of incentive stock options, non-statutory stock options, restricted stock awards, restricted stock award units, and stock appreciation rights. The 2008 Plan terminates on July 1, 2018. No shares have been issued under the 2008 Plan since 2011, and the Company does not intend to issue any additional shares from the 2008 Plan in the future. In January 2012, the Board of Directors of the Company approved the 2012 Equity Incentive Plan (the “2012 Plan”). The 2012 Plan authorized the issuance of up to 6,553,986 shares of common stock for awards of incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock, restricted stock units, performance units, performance shares, and other stock or cash awards. The Board of Directors and stockholders of the Company approved an amendment to the 2012 Plan in August 2013 to increase the number of shares of common stock that may be issued under the 2012 Plan by 5,000,000 shares. In addition, the Board of Directors and stockholders of the Company approved an amendment to the 2012 Plan in August 2015 to further increase the number of shares of common stock that may be issued under the 2012 Plan by 6,000,000 shares, bringing the aggregate shares issuable under the 2012 Plan to 17,553,986. The 2012 Plan as amended and restated became effective on August 20, 2015 and terminates ten years after such date. As of June 30, 2016, 5,575,475 shares remain available for issuance under the 2012 plan. The Company filed a shelf registration statement on Form S-3 (File No. 333-189995), or the 2013 Shelf, with the SEC on July 17, 2013 authorizing the offer and sale in one or more offerings of up to $100,000,000 in aggregate of common stock, preferred stock, debt securities, or warrants to purchase common stock, preferred stock or debt securities, or any combination of the foregoing, either individually or as units comprised of one or more of the other securities. This 2013 Shelf was declared effective by the SEC on July 26, 2013. On July 20, 2016, the Company filed a post-effective amendment to the 2013 Shelf to deregister the $26,777,784 of common stock remaining unsold as of such date under the 2013 Shelf. As a result of the post-effective amendment, no further shares of common stock may be issued pursuant to the 2013 Shelf. The Company filed a second shelf registration statement on Form S-3 (File No. 333-202382), or the 2015 Shelf, with the SEC on February 27, 2015 authorizing the offer and sale in one or more offerings of up to $190,000,000 in aggregate of common stock, preferred stock, debt securities, warrants to purchase common stock, preferred stock or debt securities, or any combination of the foregoing, either individually or as units compromised one or more of the other securities. This shelf was declared effective by the SEC on March 17, 2015. On June 18, 2015, the Company entered into an Underwriting Agreement with Jefferies LLC and Piper Jaffray & Co., acting as representatives of the underwriters named in the 2015 Underwriting Agreement and as joint book-running managers, relating to the issuance and sale of 9,425,000 shares of the Company’s common stock, par value $0.001 per share (the “2015 Offering”). The price to the public in the 2015 Offering was $4.25 per share, and the Underwriters agreed to purchase the shares from the Company pursuant to the 2015 Underwriting Agreement at a price of $3.995 per share. Under the terms of the 2015 Underwriting Agreement, the Company granted the Underwriters an option, exercisable for 30 days, to purchase up to an additional 1,413,750 shares. The Company issued 10,838,750 shares of common stock pursuant to the 2015 Underwriting Agreement, including shares issuable upon the exercise of the over-allotment option, with net proceeds of approximately $43.1 million, after deducting underwriting discounts and commissions and expenses payable by the Company. The shares were issued pursuant to the 2015 Shelf. In December 2014, the Company entered into an equity offering sales agreement, or the 2014 Sales Agreement, with Cantor Fitzgerald. Under the terms of the 2014 Sales Agreement, the Company may offer and sell shares of its common stock, from time to time, through the investment bank in at-the-market offerings and pursuant to the 2013 Shelf. During the three months ended June 30, 2016 and 2015, the Company issued no shares of common stock in at-the-market offerings under the 2014 Sales Agreement. As of June 30, 2016, the Company sold 1,000,000 shares of common stock in at-the-market offerings under the 2014 Sales Agreement, with net proceeds of approximately $6.2 million. On July 20, 2016, the Company filed a prospectus supplement to move the remaining $26,560,000 of the shares of common stock that previously could have been sold pursuant to the 2014 Sales Agreement under the 2013 Shelf to the 2015 Shelf, which does not expire until March 17, 2018. During the three months ended June 30, 2016 and 2015, the Company issued 0 and 30,186 shares of common stock upon the exercise of 0 and 38,234 warrants, respectively. Finally, during the three months ended June 30, 2016 and 2015, the Company issued 0 and 25,503 shares of common stock upon the exercise of 0 and 25,503 stock options, respectively. Restricted stock awards During the three months ended June 30, 2016 and 2015, there were 2,259 and 2,259 shares of restricted stock, respectively, cancelled related to shares of common stock returned to the Company, at the option of the holders, to cover the tax liability related to the vesting of 6,250 and 6,250 restricted stock awards, respectively. Upon the return of the common stock, an equal number of stock options with immediate vesting were granted to the individuals at the vesting date market value strike price. A summary of the Company’s restricted stock award activity from March 31, 2016 through June 30, 2016 is as follows: Number of Shares Unvested at March 31, 2016 6,250 Granted — Vested (6,250 ) Canceled / forfeited — Unvested at June 30, 2016 — The fair value of each restricted stock award is recognized as stock-based compensation expense over the vesting term of the award. The Company recorded restricted stock-based compensation expense in general and administrative expenses for employees and non-employees of approximately $3,000 and $103,000 for the three months ended June 30, 2016 and 2015, respectively. As of June 30, 2016, there was no unrecognized stock-based compensation expense for restricted stock awards. Restricted stock units During the three months ended June 30, 2016 the Company issued restricted stock units for an aggregate of 519,850 shares of common stock to its employees. These shares of common will be issued upon vesting of the restricted stock units. Vesting will occur quarterly over a four year period. A summary of the Company’s restricted stock unit activity from March 31, 2016 through June 30, 2016 is as follows: Number of Shares Weighted Average Price Unvested at March 31, 2016 — $ — Granted 519,850 $ 3.21 Vested — $ — Canceled / forfeited — $ — Unvested at June 30, 2016 519,850 $ 3.21 The fair value of each restricted common stock unit is recognized as stock-based compensation expense over the vesting term of the award. The fair value is based on the closing stock price on the date of the grant. The Company recorded restricted stock-based compensation expense in operating expenses for employees of approximately $21,000 for the three months ended June 30, 2016. Stock-based compensation expense included in research and development was $18,000 for the three months ended June 30, 2016. Stock-based compensation expense included in general and administrative expense was $3,000 for the three months ended June 30, 2016. As of June 30, 2016, total unrecognized stock-based compensation expense related to restricted stock units was approximately $1,647,000, which will be recognized over a weighted average period of 3.15 years. Stock options Under the 2012 Plan, 416,640 and 1,762,641 stock options were issued during the three months ended June 30, 2016 and 2015, respectively, at various exercise prices based on the closing market price of the Company’s common stock on the NYSE MKT on the date of the grant. The stock options generally vest (i) on the one year anniversary of the grant date, (ii) quarterly over a three year period, (iii) quarterly over a four year period, or (iv) over a four-year period, with 25% vesting on either the one year anniversary of employment or the one year anniversary of the vesting commencement date, and the remainder vesting ratably over the remaining term. A summary of the Company’s stock option activity for the three months ended June 30, 2016 is as follows: Options Outstanding Weighted- Average Exercise Price Aggregate Intrinsic Value Outstanding at March 31, 2016 9,614,627 $ 4.79 $ 1,927,137 Options granted 416,640 $ 3.21 Options canceled / forfeited (22,970 ) $ 3.64 Options exercised — $ — $ — Outstanding at June 30, 2016 10,008,297 $ 4.72 $ 7,092,419 Vested and Exercisable at June 30, 2016 5,862,904 $ 4.55 $ 5,416,930 The weighted-average remaining contractual term of options exercisable and outstanding at June 30, 2016 was approximately 6.18 years. The Company uses the Black-Scholes valuation model to calculate the fair value of stock options. Stock-based compensation expense is recognized over the vesting period using the straight-line method. The fair value of stock options was estimated at the grant date using the following weighted average assumptions: Three Months Ended Three Months Ended June 30, 2016 June 30, 2015 Dividend yield — — Volatility 71.30 % 74.25 % Risk-free interest rate 1.20 % 1.65 % Expected life of options 6.00 years 6.00 years Weighted average grant date fair value $ 2.03 $ 3.22 The assumed dividend yield was based on the Company’s expectation of not paying dividends in the foreseeable future. Due to the Company’s limited historical data, the estimated volatility incorporates the historical and implied volatility of comparable companies whose share prices are publicly available. The risk-free interest rate assumption was based on the U.S. Treasury rates. The weighted average expected life of options was estimated using the average of the contractual term and the weighted average vesting term of the options. Certain options granted to consultants are subject to variable accounting treatment and are required to be revalued until vested. The total stock option-based compensation recorded as operating expense was approximately $1,405,000 and $1,677,000 for the three months ended June 30, 2016 and 2015, respectively. Expense included in research and development was $390,000 and $349,000 for the three months ended June 30, 2016 and 2015, respectively. Expense included in general and administrative was $1,015,000 and $1,328,000 for the three months ended June 30, 2016 and 2015, respectively. The total unrecognized compensation cost related to unvested stock option grants as of June 30, 2016 was approximately $11,840,000 and the weighted average period over which these grants are expected to vest is 2.42 years. Warrants During the three months ended June 30, 2016 there were no warrant exercises. During the three months ended June 30, 2015, 38,234 warrants were exercised through a cashless exercise provision for issuance of 30,186 shares of common stock. In addition, during the three months ended June 30, 2015, a warrant that was previously expected to be issued to a service provider and had been expensed in prior periods at its approximate value of $130,000, was cancelled, and the amount was reversed against operating expense during the quarter. Of the warrants exercised during the three months ended June 30, 2016 and 2015, 0 and 38,234, respectively, were derivative liabilities and were valued at the settlement date. For the three months ended June 30, 2016 and 2015, respectively, approximately $0 and $138,000, respectively, of the warrant liability was extinguished due to the exercise of these warrants. (See Note 2). During November 2014 the Company entered into an agreement with a consultant for services. In connection with the agreement, the Company issued 145,000 warrants to purchase common stock, at a price of $6.84, with a life of five years, to be earned over a seventeen month service period ending on March 31, 2016. The final number of vested warrant shares was 95,000, based on management’s judgment of the satisfaction of specific performance metrics. The fair value of the warrants was estimated to be approximately $74,000, which was revalued and amortized over the term of the consulting agreement. The following table summarizes warrant activity for the three months ended June 30, 2016: Warrants Weighted- Average Exercise Price Balance at March 31, 2016 1,046,813 $ 2.29 Granted — $ — Exercised — $ — Cancelled — $ — Balance at June 30, 2016 1,046,813 $ 2.29 The warrants outstanding at June 30, 2016 are exercisable at prices between $0.85 and $7.62 per share, and have a weighted average remaining term of approximately 1.03 years. Common stock reserved for future issuance Common stock reserved for future issuance consisted of the following at June 30, 2016: Common stock warrants outstanding 1,046,813 Common stock options outstanding under the 2008 Plan 622,192 Common stock options outstanding and reserved under the 2012 Plan 14,961,580 Restricted stock units outstanding under the 2012 Plan 519,850 Total 17,150,435 Preferred stock The Company is authorized to issue 25,000,000 shares of preferred stock. There are no shares of preferred stock currently outstanding, and the Company has no current plans to issue shares of preferred stock. |