Warrants, stock-based compensation, stock options, restricted stock and restricted stock units | 10. Warrants, stock-based compensation, stock options, restricted stock and restricted stock units Warrants During the nine months ended September 30, 2018, the Company issued warrants to purchase common stock to a consultant providing services for the Company. Additionally, during the nine months ended September 30, 2018, warrants were exercised by a holder on a net, non-cash, basis. A summary of warrant activity is as follows: Weighted average Shares exercise price Warrants outstanding as of December 31, 2017 86,090 9.14 Granted 10,000 21.00 Exercised (20,049) 3.35 Warrants outstanding as of September 30, 2018 76,041 12.23 Stock-based compensation Share‑based compensation expense for all stock awards consists of the following (in thousands): Three months ended September 30, Nine months ended September 30, 2018 2017 2018 2017 Cost of product revenue $ 20 $ 7 $ 49 $ 18 Cost of service and other revenue 38 12 121 31 Research and development 152 53 361 126 General and administrative 1,657 551 2,862 1,256 Total $ 1,867 $ 623 $ 3,393 $ 1,431 As of September 30, 2018, under the 2007 Stock Option and Grant Plan (the 2007 Plan), options to purchase 2,015,828 shares of our common stock were outstanding, 805,853 shares of our common stock had been issued and were outstanding pursuant to the exercise of options, 1,128,975 shares of our common stock had been issued and were outstanding pursuant to restricted or unrestricted stock awards, and no shares of our common stock were available for future awards. In connection with the completion of the IPO, the Company terminated the 2007 Plan. In December 2017, the Company adopted the 2017 Employee, Director and Consultant Equity Incentive Plan (the 2017 Plan), under which it may grant incentive stock options, non‑qualified stock options, restricted stock, and other stock‑based awards. As of December 31, 2017, the 2017 Plan allowed for the issuance of up to 1,042,314 shares or options to purchase shares of common stock plus up to 2,490,290 shares of our common stock represented by awards granted under the 2007 Plan that are forfeited, expire or are cancelled without delivery of shares or which result in the forfeiture of shares of common stock back to the Company on or after the date the 2017 Plan became effective. As of September 30, 2018, 110,223 shares were available for grant under the 2017 Plan. In addition, the 2017 Plan contains an “evergreen” provision, which allows for an annual increase in the number of shares of common stock available for issuance under the 2017 Plan on the first day of each fiscal year during the period beginning in fiscal year 2019 and ending in fiscal year 2027. The annual increase in the number of shares shall be equal to the lowest of: 4% of the number of shares of common stock outstanding as of such date; and an amount determined by the Company’s Board of Directors or Compensation Committee. In December 2017, the Company adopted the 2017 Employee Stock Purchase Plan (the 2017 ESPP). As of September 30, 2018, the 2017 ESPP allowed for the issuance of up to 427,305 shares of common stock and 427,305 shares were available for grant under the 2017 ESPP. The 2017 ESPP contains an “evergreen” provision, which allows for an increase on the first day of each fiscal year beginning with fiscal year 2018. The increase in the number of shares shall be equal to the lowest of: 1% of the number of shares of common stock outstanding on the last day of the immediately preceding fiscal year or an amount determined by the Company’s Board of Directors or Compensation Committee. The number of shares available for grant under the 2017 ESPP increased by 218,842 on January 1, 2018 due to this provision. Stock options Under the 2007 Plan and 2017 Plan, stock options may not be granted with exercise prices of less than fair market value on the date of the grant. Options generally vest ratably over a four‑year period with 25% vesting on the first anniversary and the remaining 75% vesting ratably on a monthly basis over the remaining three years. These options expire ten years after the grant date. Activity under the 2007 Plan and the 2017 Plan was as follows: Weighted- Remaining Aggregate average contractual intrinsic exercise life value Options price (in years) (in thousands) Outstanding at December 31, 2017 2,249,843 6.05 7.80 $ 34,695 Granted 629,703 $ 18.57 Exercised (234,015) $ 2.92 Cancelled or forfeited (79,624) $ 12.58 Outstanding at September 30, 2018 2,565,907 $ 9.21 7.85 $ 31,368 Vested and expected to vest at September 30, 2018 2,565,907 $ 9.21 7.85 $ 31,368 Exercisable at September 30, 2018 1,160,407 $ 5.22 6.57 $ 18,795 Using the Black-Scholes option pricing model, the weighted-average fair value of options granted to employees and directors during the nine months ended September 30, 2018 and 2017 was $7.32 and $4.50 per share, respectively. The expense related to awards granted to employees was $0.7 million and $1.8 million for the three and nine months ended September 30, 2018, respectively. The expense related to awards granted to employees was $0.4 million and $0.9 million for the three and nine months ended September 30, 2017, respectively. The intrinsic value of stock options exercised was $0.6 million and $3.4 million for the three and nine months ended September 30, 2018, respectively. The intrinsic value of stock options exercised was less than $0.1 million and $0.2 million for the three and nine months ended September 30, 2017, respectively. Activity related to non-employee awards was not material to the three and nine months ended September 30, 2018 and 2017. At September 30, 2018, there was $7.1 million of total unrecognized compensation cost related to unvested stock options, which is expected to be recognized over the remaining weighted‑average vesting period of 2.81 years. The fair value of stock options granted to employees and directors for their services on the Company’s Board of Directors is estimated on the grant date using the Black‑Scholes option‑pricing model, based on the assumptions noted in the following table: Nine months ended September 30, 2018 2017 Risk - free interest rate 2.82 % 2.0 % Expected dividend yield None None Expected term (in years) 5.85 6.0 Expected volatility 34.98 % 51.7 % Restricted stock Restricted common stock awards represent shares of common stock issued to employees subject to forfeiture if the vesting conditions are not satisfied. In December 2014, the Company issued 78,912 shares of restricted common stock to a director of the Company under the 2007 Plan. Under the terms of the agreement, shares of common stock issued are subject to a four year vesting schedule. Vesting occurs periodically at specified time intervals and specified percentages. In January 2015, the Company issued 781,060 shares of restricted common stock to an executive of the Company under the 2007 Plan. The majority of these shares were issued subject to a four year vesting schedule with 25% vesting on the first anniversary and the remaining vesting 75% ratably on a monthly basis over the remaining three years, while another portion was issued subject to performance based vesting. The vesting of performance based awards is dependent upon achievement of specified financial targets of the Company. The majority of the performance criteria were achieved during the years ended December 31, 2016 and 2015 and the remaining unvested awards with performance conditions are not material. No restricted stock awards were granted during the nine months ended September 30, 2018. A summary of restricted stock activity is as follows: Weighted-average grant date fair value Shares per share Unvested restricted common stock as of December 31, 2017 177,192 $ 3.11 Vested (137,386) $ 3.11 Unvested restricted common stock as of September 30, 2018 39,806 $ 3.12 The expense related to awards granted to employees and directors was $0.1 million and $0.4 million for the three and nine months ended September 30, 2018, respectively. The expense related to awards granted to employees and directors was $0.2 million and $0.5 million for the three and nine months ended September 30, 2017, respectively. At September 30, 2018, there was $0 million of total unrecognized compensation cost related to unvested restricted stock, which is expected to be recognized over the remaining weighted‑average vesting period of 0 years. The aggregate fair value of restricted stock awards that vested during the nine months ended September 30, 2018, based on estimated fair values of the stock underlying the restricted stock awards on the day of vesting, was $1.9 million. Restricted stock units Restricted stock units represent the right to receive shares of common stock upon meeting specified vesting requirements. In the nine months ended September 30, 2018, the Company issued 393,386 restricted stock units to employees of the Company under the 2017 Plan. Under the terms of the agreements, 56,196 of the restricted stock units issued are subject to a four year vesting schedule with 25% vesting on the first anniversary and the remaining vesting 75% ratably on a monthly basis over the remaining three years, 18,200 of the restricted stock units issued are subject to vesting with 50% vesting on December 31, 2018 and 50% vesting on December 31, 2019, 3,100 of the restricted stock units are subject to a four year vesting schedule with 25% vesting on each anniversary, 15,890 of the restricted stock units vest on December 31, 2018, 50,000 of the restricted stock units vested on August 31, 2018, and 250,000 of the restricted stock units vest evenly over 40 months on the last day of each month starting September 30, 2018. A summary of restricted stock unit activity is as follows: Weighted-average grant date fair value Shares per share Unvested restricted stock units as of December 31, 2017 — — Granted 393,386 $ 15.60 Unvested restricted stock units as of September 30, 2018 393,386 $ 15.60 The expense related to awards granted to employees and directors was $1.1 million for the three and $1.2 million for the nine months ended September 30, 2018. At September 30, 2018, there was $5.0 million of total unrecognized compensation cost related to unvested restricted stock, which is expected to be recognized over the remaining weighted‑average vesting period of 3.13 years. |