Stockholders' Equity | Note Stock-based compensation expense and valuation information Stock-based compensation expense for all stock awards consists of the following (in thousands): Three Months Ended Three Months Ended Six Months Ended Six Months Ended September 30, 2017 September 30, 2016 September 30, 2017 September 30, 2016 Research and development $ 384 $ 379 $ 715 $ 787 General and administrative $ 1,914 $ 1,714 $ 3,635 $ 2,735 Total $ 2,298 $ 2,093 $ 4,350 $ 3,522 The total unrecognized compensation cost related to unvested stock option grants as of September 30, 2017 was approximately $10,527,000 and the weighted average period over which these grants are expected to vest is 2.43 years. The total unrecognized compensation cost related to unvested restricted stock units (not including performance-based restricted stock units) as of September 30, 2017 was approximately $7,027,000, which will be recognized over a weighted average period of 3.18 years. The total unrecognized compensation cost related to unvested performance-based restricted stock units as of September 30, 2017 was approximately $378,000 which will be recognized over a weighted average period of 2.16 years. As of September 30, 2017, there was no unrecognized stock-based compensation expense for restricted stock awards. The total unrecognized stock-based compensation cost related to unvested ESPP shares as of September 30, 2017 was approximately $25,000, which will be recognized over a period of 5 months. The Company calculates the grant date fair value of all stock-based awards in determining the stock-based compensation expense. Stock-based awards include (i) stock options, (ii) restricted stock awards, (iii) restricted stock units, and (iv) rights to purchase stock under the 2016 Employee Stock Purchase Plan. 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, 2017 September 30, 2016 September 30, 2017 September 30, 2016 Dividend yield — — — — Volatility 70.97% 72.28% 76.85% 72.04% Risk-free interest rate 1.78% 1.07% 1.81% 1.1% Expected life of options 6.00 years 6.00 years 6.00 years 6.00 years Weighted average grant date fair value $ 1.25 $ 2.57 $ 1.73 $ 2.44 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 as an early-stage commercial business, 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 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 fair value of each restricted stock unit and performance-based 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 fair value of each restricted stock award 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 uses the Black-Scholes valuation model to calculate the fair value of shares issued pursuant to the Company’s ESPP. 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 assumptions: Three Months Ended Three Months Ended Six Months Ended Six Months Ended September 30, 2017 September 30, 2016 September 30, 2017 September 30, 2016 Dividend yield — — — — Volatility 43.03 - 74.70% 72.89% 43.03 - 74.70% 72.89% Risk-free interest rate 0.79 - 1.10% 0.47% 0.79 - 1.10% 0.47% Expected term 6 months 6 months 6 months 6 months Weighted average grant date fair value $0.52 - $1.04 $1.22 $0.52 - $1.04 $1.22 The assumed dividend yield was based on the Company’s expectation of not paying dividends in the foreseeable future. For the first full year of ESPP offering periods, beginning September 1, 2016, due to the Company’s limited historical data as an early-stage commercial business, the estimated volatility incorporates the historical and implied volatility of comparable companies whose share prices are publicly available. As of September 1, 2017 and the beginning of the second year of ESPP offering periods, the Company is using our Company-specific volatility rate. The risk-free interest rate assumption was based on U.S. Treasury rates. The expected life is the 6-month purchase period. 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. 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, 2017, 2,117,682 shares remain available for issuance under the 2012 Plan. On April 24, 2017, the Company filed a Registration Statement on Form S-8 with the SEC authorizing the issuance of 2,297,034 shares of the Company’s common stock, pursuant to the terms of an Inducement Award Stock Option Agreement and an Inducement Award Performance-Based Restricted Stock Unit Agreement (collectively, the “Inducement Award Agreements”). 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 and was terminated in 2016. A shelf registration statement on Form S-3 (File No. 333-202382), or the 2015 shelf, was filed 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 comprised of one or more of the other securities. The 2015 shelf was declared effective by the SEC on March 17, 2015. In December 2014, the Company entered into an equity offering sales agreement, or the 2014 Sales Agreement, with an investment banking firm. Under the terms of the distribution agreement, the Company could offer and sell up to $30,000,000 of its shares of common stock, from time to time, through the investment bank in at-the-market offerings, as defined by the SEC, and pursuant to the 2013 Shelf. On July 20, 2016, the Company filed a prospectus supplement to move the remaining $26.6 million 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. On that same date, the Company filed a post-effective amendment to the 2013 Shelf de-registering all remaining securities that could have been offered by the Company pursuant to the 2013 Shelf. On June 23, 2015, the Company closed the public offering of 10,838,750 shares of its common stock (the “2015 Offering”), which included the full exercise of the underwriters’ over-allotment. The 2015 Offering was effected pursuant to an Underwriting Agreement (the “2015 Underwriting Agreement”), dated June 18, 2015, with Jefferies LLC and Piper Jaffray & Co. (the “Representatives”), acting as representatives of the underwriters named in the 2015 Underwriting Agreement. 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. On October 25, 2016, the Company closed the public offering of 10,065,000 shares (the “2016 Offering”) of its common stock, which included partial exercise of the underwriters’ over-allotment. 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 $25.7 million after deducting underwriting discounts and commissions and expenses payable by the Company. The 2016 Offering was made pursuant to the 2015 Shelf. During the three months ended September 30, 2017 and 2016, the Company issued 0 and 123,104 shares of common stock upon the exercise of 0 and 160,000 warrants, respectively. During the six months ended September 30, 2017 and 2016, the Company issued 0 and 123,104 shares of common stock up on the exercise of 0 and 160,000 warrants, respectively. During the three months ended September 30, 2017 and 2016, the Company issued 500,000 and 206,266 shares of common stock upon the exercise of 500,000 and 206,266 stock options, respectively. During the six months ended September 30, 2017 and 2016, the Company issued 500,000 and 206,266 shares of common stock upon the exercise of 500,000 and 206,266 stock options, respectively. Restricted stock awards During the three months ended September 30, 2017 and 2016, there were 0 and 0 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 0 restricted stock awards, respectively. During the six months ended September 30, 2017 and 2016, there were 0 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 0 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. Restricted stock units During the three and six months ended September 30, 2017, the Company issued restricted stock units for an aggregate of 7,000 and 1,869,078 shares of common stock, respectively, to its employees and directors. These shares of common stock 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 (not including performance-based restricted stock units) activity from March 31, 2017 through September 30, 2017 is as follows: Number of Shares Weighted Average Price Unvested at March 31, 2017 1,178,114 $ 3.57 Granted 1,869,078 $ 2.66 Vested (263,594 ) $ 3.45 Cancelled / forfeited (154,924 ) $ 3.04 Unvested at September 30, 2017 2,628,674 $ 2.96 Performance-based restricted stock units On April 24, 2017, in connection with the appointment of a new CEO, the Company allocated 208,822 Performance-Based Restricted Stock Units outside of the 2012 Plan. The Company intends for these to be “inducement awards” within the meaning of NASDAQ Marketplace Rule 5635(c)(4). While outside the Company’s 2012 Plan, the terms and conditions of these awards are consistent with awards granted to the Company’s executive officers pursuant to the 2012 Plan. On August 23, 2017, the Board of Directors formally approved the vesting criteria for the Performance-Based Restricted Stock Units (“PBRSUs”) allocated by the Company on April 24, 2017. The units are divided into five separate tranches each with independent vesting criteria. The first four tranches have performance criteria related to annual revenue goals with measurement at the end of fiscal year 2018 (20 percent), fiscal year 2019 (20 percent), fiscal year 2020 (20 percent), and fiscal year 2021 (20 percent). The fifth tranche has a performance metric related to a path to profitability goal measured as Negative Adjusted EBITDA achievable at any point between the grant date and the end of fiscal year 2020 (20 percent). The number of units that ultimately vest for each tranche will range from 0 percent to 120 percent of the target amount, not to exceed 208,822 in aggregate. As of September 30, 2017, no tranches had vested and 100% of current year tranches are expected to vest. The grant date fair values of the tranches are collectively $393,000 of which one-fifth is being recognized over each tranches’ service period. The Company began recording stock-based compensation expense for these tranches after the August 23, 2017 grant date when the financial performance goals were established and approved. As of September 30, 2017, PBRSUs from the fiscal year 2018 tranche and the Negative Adjusted EBITDA tranche have begun vesting and are expected to vest in the amount of 83,530 shares. A summary of the Company’s performance-based restricted stock unit activity from March 31, 2017 through September 30, 2017 is as follows: Number of Shares Weighted Average Price Unvested at March 31, 2017 — $ — Granted 208,822 $ 1.88 Vested — $ — Cancelled / forfeited — $ — Unvested at September 30, 2017 208,822 $ 1.88 Stock options Under the 2012 Plan, 260,000 and 1,386,500 stock options were issued during the three months ended September 30, 2017 and 2016, respectively, and 2,366,812 and 1,803,140 stock options were issued during the six months ended September 30, 2017 and 2016, 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, or (iii) over a four-year period with a quarter 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 36 month terms. Stock options can also vest immediately at the grant date or vest after one full year. On April 24, 2017, in connection with the appointment of a new CEO, the Company granted 2,088,212 stock options outside of the 2012 Plan. The Company intends for these to be “inducement grants” within the meaning of NASDAQ Marketplace Rule 5635(c)(4). While granted outside the Company’s 2012 Plan, the terms and conditions of these awards are consistent with awards granted to the Company’s executive officers pursuant to the 2012 Plan. These stock options vest A summary of the Company’s stock option activity from March 31, 2017 to September 30, 2017 is as follows: Options Outstanding Weighted- Average Exercise Price Aggregate Intrinsic Value Outstanding at March 31, 2017 10,956,201 $ 4.63 $ 4,876,437 Options granted 2,366,812 $ 2.65 $ — Options cancelled / forfeited (493,050 ) $ 4.41 $ — Options exercised (500,000 ) $ 1.65 $ 235,000 Outstanding at September 30, 2017 12,329,963 $ 4.38 $ 1,812,776 Vested and Exercisable at September 30, 2017 7,265,871 $ 4.92 $ 1,723,601 The weighted-average remaining contractual term of options exercisable and outstanding at September 30, 2017 was approximately 6 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. 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 the lower of $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, 2017, there were 1,372,960 shares available for purchase under the ESPP. Warrants During the three and six months ended September 30, 2017, there were no warrant exercises. 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. The following table summarizes warrant activity for the six months ended September 30, 2017: Warrants Weighted- Average Exercise Price Balance at March 31, 2017 221,370 $ 7.16 Granted — $ — Exercised — $ — Cancelled — $ — Balance at September 30, 2017 221,370 $ 7.16 The warrants outstanding at September 30, 2017 are exercisable at prices between $2.28 and $7.62 per share, and have a weighted average remaining term of approximately 1.36 years. Common stock reserved for future issuance Common stock reserved for future issuance consisted of the following at September 30, 2017: Common stock warrants outstanding 221,370 Common stock options outstanding under the 2008 Plan 622,192 Common stock options outstanding and reserved under the 2012 Plan 11,737,241 Common stock reserved under the 2016 Employee Stock Purchase Plan 1,372,960 Restricted stock units outstanding under the 2012 Plan 2,628,674 Common stock options outstanding and reserved under the Inducement Awards 2,088,212 Restricted stock units outstanding under the Inducement Awards 208,822 Total at September 30, 2017 18,879,471 |