Stock-based Compensation | Stock-based Compensation The Company recorded stock-based compensation expense related to stock options and shares issued under the Company's 2010 Stock Incentive Plan and 2017 Employee Stock Purchase Plan (2017 Plan) in the following expense categories of its accompanying consolidated statements of operations for the three and six months ended June 30, 2022 and 2021: Three Months Ended Six Months Ended 2022 2021 2022 2021 Cost of product sales $ 7 $ 6 $ 20 $ 17 Research and development 233 286 429 567 General and administrative 3,204 2,441 4,995 4,759 $ 3,444 $ 2,733 $ 5,444 $ 5,343 In addition, stock-based compensation expense of $85 and $1 was charged to inventory and prepaid expenses and other assets, respectively, during the six months ended June 30, 2022, which represents the total stock-based compensation expense incurred related to employees involved in the manufacturing process of finished goods and samples during the period. Stock Options The Company issues stock-based awards pursuant to its 2010 Stock Incentive Plan. Effective as of October 12, 2017, the Company's 2010 Stock Incentive Plan was amended and restated (A&R Plan).The Company has issued service-based, performance-based, and market-based stock options that generally have a contractual life of up to 10 years and may be exercisable in cash or as otherwise determined by the Company's board of directors or committee thereof. Vesting generally occurs over a period of not greater than four years. Performance-based options may vest upon the achievement of certain milestones. As of June 30, 2022, all of the performance conditions related to performance-based stock options issued by the Company had been achieved. Market-based options may vest upon the achievement of certain market-based objectives relating to the trading price of the Common Stock. The following table summarizes the activity related to stock option grants to employees and non-employees for the six months ended June 30, 2022: Shares Weighted Weighted Outstanding at December 31, 2021 7,958,781 $ 8.87 6.50 Granted 2,902,370 1.88 Exercised (67,125) 1.63 Expired (135,983) 8.89 Forfeited (422,129) 3.86 Outstanding at June 30, 2022 10,235,914 $ 7.65 6.62 Exercisable at June 30, 2022 5,819,746 $ 10.37 5.26 Vested and expected to vest at June 30, 2022 9,342,884 $ 7.65 6.62 During the six months ended June 30, 2022, stock options to purchase 2,902,370 shares of Common Stock were granted to employees and generally vest over four years. Included in the total stock options granted were market-based options to purchase 959,215 shares of Common Stock. The stock options, including the market-based options, had an estimated weighted average grant date fair value of $1.19. During the six months ended June 30, 2021, stock options to purchase 1,542,696 shares of Common Stock were granted to employees that generally vest over four years. The stock options had an estimated weighted average grant date fair value of $2.29. The grant date fair value of each stock option grant, other than market-based stock option grants, was estimated at the time of grant using the Black-Scholes option-pricing model using the following weighted average assumptions: Six Months Ended June 30, 2022 2021 Risk free interest rate 1.82 % 1.00 % Expected term (in years) 6.08 6.08 Expected volatility 72.67 % 74.28 % Annual dividend yield 0.00 % 0.00 % Fair value of common stock $ 1.90 $ 3.52 At June 30, 2022, the unrecognized compensation cost related to unvested stock options, other than market-based stock options, expected to vest was $6,655. This unrecognized compensation will be recognized over an estimated weighted-average amortization period of 2.28 years. During the six months ended June 30, 2022, market-based options to purchase 959,215 shares of Common Stock were granted to employees and generally become eligible to vest over four years, subject to the achievement of certain market-based objectives relating to the trading price of the Common Stock. Stock based compensation for these awards is recognized over the derived service period of approximately 2 years. The grant date fair value of each stock option grant, as well as the derived service period for these awards, was estimated at the time of grant using a Monte Carlo simulation based on the following assumptions: Six Months Ended 2022 Risk free rates of return 1.70 % Expected volatility 75.00 % Annual dividend yield — % Restricted Stock Units The Company has issued service-based and performance-based restricted stock units (RSUs). Vesting generally occurs over a period not greater than four years. Vesting of the performance-based RSUs is subject to the achievement of certain milestones in connection with the Company's development programs. The following table summarizes the activity related to RSUs granted to employees for the six months ended June 30, 2022: Shares Outstanding at December 31, 2021 1,959,358 Granted 1,105,246 Vested and settled (598,775) Expired/forfeited/canceled (264,146) Outstanding at June 30, 2022 2,201,683 Expected to vest at June 30, 2022 2,201,683 During the six months ended June 30, 2022, the Company granted 1,105,246 RSUs at a grant date fair value of $1.85, all of which were service-based RSUs. No performance-based RSUs were granted in 2022. As of June 30, 2022, one of the milestones associated with the previously granted performance based-RSUs was achieved. As a result 248,830 RSUs vested on June 15, 2022 and stock based compensation expense of $1,346 was recognized for these awards. At June 30, 2022, the unrecognized compensation cost related to unvested service-based RSUs expected to vest was $5,041, to be recognized over an estimated weighted-average amortization period of 2.63 years. The unrecognized compensation cost related to unvested performance-based RSUs was $1,749, which will be recognized over the remaining service period. Included in the table above are 60,000 RSUs granted outside the A&R Plan. The grants were made pursuant to the Nasdaq inducement grant exception in accordance with Nasdaq Listing Rule 5635(c)(4). 2017 Employee Stock Purchase Plan Under the 2017 Plan, shares of Common Stock may be purchased by eligible employees who elect to participate in the 2017 Plan at 85% of the lower of the fair market value of Common Stock on the first or last day of designated offering periods. The Company recognized stock-based compensation expense of $74 and $91 during the three months ended June 30, 2022 and 2021, respectively, and $162 and $199 during the six months ended June 30, 2022 and 2021, respectively, related to the 2017 Plan. The Company calculated the fair value of each option grant and the shares issued under the 2017 Plan on the respective dates of grant using the following weighted average assumptions: Six Months Ended June 30, 2022 2021 Risk free interest rate 0.22 % 0.09 % Expected term (in years) 0.5 0.5 Expected volatility 88.56 % 86.88 % Annual dividend yield 0.00 % 0.00 % |