Warrants, stock-based compensation, stock options, restricted stock and restricted stock units | 9. Warrants, stock-based compensation, stock options, restricted stock and restricted stock units Warrants On July 2, 2019, 66,041 warrants were exercised by a holder on a net, non-cash, basis. Per terms of the warrant agreement, the Company issued 45,690 shares of common stock with a value equal to the holder’s gain. The Company issued no warrants during the nine months ended September 30, 2019, and had 10,000 warrants outstanding as of September 30, 2019. Stock-based compensation Stock‑based compensation expense for all stock awards consists of the following (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Cost of product revenue $ 31 $ 20 $ 75 $ 49 Cost of service and other revenue 58 38 175 121 Research and development 175 152 523 361 Selling, general, and administrative 1,564 1,657 3,940 2,862 Total $ 1,828 $ 1,867 $ 4,713 $ 3,393 As of September 30, 2019, under the 2007 Stock Option and Grant Plan (the 2007 Plan), options to purchase 1,324,255 shares of common stock were outstanding and no shares of 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. Upon its adoption, the 2017 Plan allowed for the issuance of up to 1,042,314 shares of common stock plus up to 2,490,290 shares of 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. 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. The number of shares available for grant under the 2017 Plan increased by 894,761 on January 1, 2019 due to this provision. As of September 30, 2019, under the 2017 Plan, options to purchase 1,338,079 shares of common stock were outstanding and unvested restricted stock units for 422,336 shares of common stock were outstanding. As of September 30, 2019, 207,589 shares were available for grant under the 2017 Plan. In December 2017, the Company adopted the 2017 Employee Stock Purchase Plan (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 223,690 on January 1, 2019 due to this provision. As of September 30, 2019, the 2017 ESPP allowed for the issuance of up to 649,223 shares of common stock and 612,470 shares were available for issuance under the 2017 ESPP. Stock options Under the 2007 Plan and the 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-average Remaining contractual Aggregate intrinsic value Options exercise price life (in years) (in thousands) Outstanding at December 31, 2018 2,476,911 $ 9.65 7.73 $ 22,108 Granted 818,918 $ 24.25 Exercised (322,250) $ 6.74 Cancelled (311,245) $ 13.45 Outstanding at September 30, 2019 2,662,334 $ 14.04 7.72 $ 23,476 Vested and expected to vest at September 30, 2019 2,662,334 $ 14.04 7.72 $ 23,476 Exercisable at September 30, 2019 1,234,533 $ 7.91 6.40 $ 17,394 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, 2019 and 2018 was $8.85 and $7.32 per share, respectively. The expense related to awards granted to employees was $1.0 million and $2.7 million for the three and nine months ended September 30, 2019, 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 intrinsic value of stock options exercised was $1.3 million and $5.5 million for the three and nine months ended September 30, 2019, 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. Activity related to non-employee awards was not material to the three and nine months ended September 30, 2019 and 2018. 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 common stock awards were granted or vested during the nine months ended September 30, 2019. Restricted stock units Restricted stock units (RSUs) represent the right to receive shares of common stock upon meeting specified vesting requirements. In the nine months ended September 30, 2019, the Company issued 227,653 RSUs to employees of the Company under the 2017 Plan. Under the terms of the agreements, 135,058 of the RSUs issued are subject to a four-year vesting schedule with 25% vesting on the first anniversary of the grant date and the remaining vesting 75% ratably on a monthly basis over the remaining three years; 15,890 of the RSUs vest on December 31, 2019; 24,233 of the RSUs vest in equal amounts annually over four years; 10,194 of the RSUs vested with respect to 5/48 th of the shares on the date of grant with the rest vesting ratably over the remaining 43 months; 31,732 of the RSUs vested with respect to 1,983 shares vesting on the grant date with the rest vesting ratably over the remaining 45 months; 4,540 of the RSUs vest equally over three years on the anniversary of the vesting start date; 3000 of the RSUs vest upon the one year anniversary of the grant date; and 3,006 vested immediately upon grant. A summary of RSU activity is as follows: Weighted-average grant date fair value Shares per share Unvested RSUs as of December 31, 2018 321,662 $ 15.84 Granted 227,653 $ 24.21 Vested (83,996) $ 16.65 Cancelled (42,983) $ 18.17 Unvested RSUs as of September 30, 2019 422,336 $ 19.90 The expense related to awards granted to employees and directors was $0.8 million and $2.0 million for the three and nine months ended September 30, 2019, respectively, and $1.1 million and $1.2 million for the three and nine months ended September 30, 2018, respectively. At September 30, 2019, there was $7.6 million of total unrecognized compensation cost related to unvested restricted stock units, which is expected to be recognized over the remaining weighted‑average vesting period of 2.94 years. |