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 September 30, 2016, 3,578,760 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. The 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. The 2015 Shelf was declared effective by the SEC on March 17, 2015. On October 25, 2016, the Company closed the issuance and sale of 10,065,000 shares (the “2016 Offering”) of its common stock. The 2016 Offering was effected pursuant to an Underwriting Agreement (the “2016 Underwriting Agreement”), dated October 20, 2016, with Jefferies LLC (the “Representative”), acting as representative of the underwriters named in the 2016 Underwriting Agreement. The price to the public in the 2016 Offering was $2.75 per share, and the underwriters purchased the shares from the Company pursuant to the 2016 Underwriting Agreement at a price of $2.585 per share. The net proceeds to the Company from the 2016 Offering were approximately $25.6 million after deducting underwriting discounts and commissions and estimated expenses payable by the Company. The 2016 Offering was made pursuant to the Company’s 2015 Shelf. 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. During the three and six months ended September 30, 2015, the Company issued no shares of common stock in at-the-market offerings under the 2014 Sales Agreement. During the three and six months ended September 30, 2016, the Company issued 997,181 shares of common stock in at-the-market offerings under the 2014 Sales Agreement with net proceeds of approximately $4.5 million, after deducting underwriting discounts and commissions and expenses payable by the Company. As of September 30, 2016, the Company has sold an aggregate of 1,997,181 shares of common stock in at-the-market offerings under the 2014 Sales Agreement, with net proceeds of approximately $10.8 million. On July 20, 2016, the Company filed a prospectus supplement to move the remaining 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. Based on sales through September 30, 2016, the Company can sell an additional $21.9 million of shares pursuant to the 2014 Sales Agreement under the 2015 Shelf. During the three months ended September 30, 2016 and 2015, the Company issued 123,104 and 0 shares of common stock upon the exercise of 160,000 and 0 warrants, respectively. During the six months ended September 30, 2016 and 2015, the Company issued 123,104 and 30,186 shares of common stock upon the exercise of 160,000 and 38,234 warrants, respectively. Finally, during the three months ended September 30, 2016 and 2015, the Company issued 206,266 and 2,060 shares of common stock upon the exercise of 206,266 and 2,060 stock options, respectively. During the six months ended September 30, 2016 and 2015, the Company issued 206,266 and 27,563 shares of common stock upon exercise of 206,266 and 27,563 stock options, respectively. Restricted stock awards During the three months ended September 30, 2016 and 2015, there were 0 and 100,692 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 0 and 187,500 restricted stock awards, respectively. During the six months ended September 30, 2016 and 2015, there were 2,259 and 102,951 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 193,750 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 September 30, 2016 is as follows: Number of Shares Unvested at March 31, 2016 6,250 Granted — Vested (6,250 ) Canceled / forfeited — Unvested at September 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 $0 and $71,000 for the three months ended September 30, 2016 and 2015, respectively, and approximately $3,000 and $174,000 for the six months ended September 30, 2016 and 2015, respectively. The Company recorded restricted stock-based compensation expense in research and development expenses for employees of approximately $0 and $3,000 for the three months ended September 30, 2016 and 2015, respectively, and approximately $0 and $3,000 for the six months ended September 30, 2016 and 2015, respectively. As of September 30, 2016, there was no unrecognized stock-based compensation expense for restricted stock awards. Restricted stock units During the three and six months ended September 30, 2016, the Company issued restricted stock units for an aggregate of 645,900 and 1,165,750 shares of common stock, respectively, to its employees and directors. These shares of common will be issued upon vesting of the restricted stock units. Vesting generally occurs (i) on the one-year anniversary of the grant date, (ii) quarterly over a three-year period, (iii) quarterly over a four-year period, (iv) over a four-year period, with 25% vesting on the one-year anniversary of the vesting commencement date and the remainder vesting ratably on a quarterly basis over the next twelve quarters, or (v) over a three-year period with 50% vesting on the two-year anniversary of the vesting commencement date and 50% vesting on the three-year anniversary of the vesting commencement date. A summary of the Company’s restricted stock unit activity from March 31, 2016 through September 30, 2016 is as follows: Number of Shares Weighted Average Price Unvested at March 31, 2016 — $ — Granted 1,165,750 $ 3.66 Vested (34,581 ) $ 3.85 Canceled / forfeited (1,700 ) $ 3.21 Unvested at September 30, 2016 1,129,469 $ 3.66 The fair value of each restricted 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 $349,000 and $370,000 for the three and six months ended September 30, 2016, respectively. Stock-based compensation expense included in research and development was $114,000 and $132,000 for the three and six months ended September 30, 2016, respectively. Stock-based compensation expense included in general and administrative expense was $235,000 and $238,000 for the three and six months ended September 30, 2016, respectively. As of September 30, 2016, total unrecognized stock-based compensation expense related to restricted stock units was approximately $3,896,000, which will be recognized over a weighted average period of 3.25 years. Stock options Under the 2012 Plan, 1,386,500 and 692,092 stock options were issued during the three months ended September 30, 2016 and 2015, respectively, and 1,803,140 and 2,454,733 stock options were issued during the six months ended September 30, 2016 and 2015, respectively, at various exercise prices based on the closing market price of the Company’s common stock 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 the one-year anniversary of the vesting commencement date, and the remainder vesting on a monthly basis ratably over the remaining term. A summary of the Company’s stock option activity for the six months ended September 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 1,803,140 $ 3.85 Options canceled / forfeited (56,955 ) $ 5.05 Options exercised (206,266 ) $ 2.42 $ 328,691 Outstanding at September 30, 2016 11,154,546 $ 4.68 $ 7,439,063 Vested and Exercisable at September 30, 2016 6,347,222 $ 4.59 $ 6,054,006 The weighted-average remaining contractual term of options exercisable and outstanding at September 30, 2016 was approximately 5.96 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 Six Months Ended Six Months Ended September 30, 2016 September 30, 2015 September 30, 2016 September 30, 2015 Dividend yield — — — — Volatility 72.28 % 74.26 % 72.04 % 74.25 % Risk-free interest rate 1.07 % 1.48 % 1.10 % 1.60 % Expected life of options 6.00 years 6.00 years 6.00 years 6.00 years Weighted average grant date fair value $ 2.57 $ 1.39 $ 2.44 $ 2.70 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 $1,734,000 and $2,098,000 for the three months ended September 30, 2016 and 2015, respectively, and $3,139,000 and $3,775,000 for the six months ended September 30, 2016 and 2015, respectively. Expense included in research and development was $260,000 and $277,000 for the three months ended September 30, 2016 and 2015, respectively, and $650,000 and $626,000 for the six months ended September 30, 2016 and 2015, respectively. Expense included in general and administrative was $1,474,000 and $1,821,000 for the three months ended September 30, 2016 and 2015, respectively, and $2,489,000 and $3,149,000 for the six months ended September 30, 2016 and 2015, respectively. The total unrecognized compensation cost related to unvested stock option grants as of September 30, 2016 was approximately $13,580,000 and the weighted average period over which these awards are expected to vest is 2.52 years. Employee Stock Purchase Plan In June 2016, our Board of Directors adopted, and in August 2016 stockholders subsequently approved, the 2016 Employee Stock Purchase Plan (“ESPP”). We reserved 1,500,000 shares of common stock for issuance thereunder. The ESPP permits employees after five months of service to purchase common stock through payroll deductions, limited to 15 percent of each employee’s compensation up to $25,000 or 10,000 shares per employee per year. Shares under the ESPP are purchased at 85 percent of the fair market value at the lower of (i) the closing price on the first trading day of the six-month purchase period or (ii) the closing price on the last trading day of the six-month purchase period. The initial offering period commenced in September 2016. At September 30, 2016, there were 1,500,000 shares available for purchase under the ESPP. The Company uses the Black-Scholes valuation model to calculate the fair value of ESPP shares. Stock-based compensation expense is recognized over the purchase period using the straight-line method. The fair value of ESPP shares was estimated at the purchase period commencement date using the following weighted average assumptions: Three Months Ended Six Months Ended September 30, 2016 September 30, 2016 Dividend yield — — Volatility 72.89 % 72.89 % Risk-free interest rate 0.47 % 0.47 % Expected term 0.50 years 0.50 years Weighted average grant date fair value $ 1.22 $ 1.22 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 expected life is the 6-month purchase period. Warrants During the three and six months ended September 30, 2016, 160,000 warrants were exercised through a cashless exercise provision in exchange for the issuance of 123,104 shares of common stock. During the three and six months ended September 30, 2015, 0 and 38,234 warrants were exercised through a cashless exercise provision in exchange for the issuance of 0 and 30,186 shares of common stock. In addition, during the six ended September 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 period. Of the warrants exercised during the six months ended September 30, 2016 and 2015, 0 and 38,234, respectively, were derivative liabilities and were valued at the settlement date. For the six months ended September 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 six months ended September 30, 2016: Warrants Weighted- Average Exercise Price Balance at March 31, 2016 1,046,813 $ 2.29 Granted — $ — Exercised (160,000 ) $ 1.00 Cancelled — $ — Balance at September 30, 2016 886,813 $ 2.52 The warrants outstanding at September 30, 2016 are exercisable at prices between $0.85 and $7.62 per share, and have a weighted average remaining term of approximately 0.86 years. Common stock reserved for future issuance Common stock reserved for future issuance consisted of the following at September 30, 2016: Common stock warrants outstanding 886,813 Common stock options outstanding under the 2008 Plan 622,192 Common stock options outstanding and reserved under the 2012 Plan 14,111,114 Common stock reserved under the 2016 Employee Stock Purchase Plan 1,500,000 Restricted stock units outstanding under the 2012 Plan 1,129,469 Total 18,249,588 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. |