Stock Plans | NOTE 9. STOCK PLANS Stock-Based Compensation During the six months ended June 30, 2021, the Company granted options to purchase an aggregate of 200,955 shares of its common stock that are subject to time-based vesting conditions. The Company valued these stock options using the Black-Scholes Merton option pricing model. The following assumptions were used to compute the grant date fair values of the stock options granted during the six months ended June 30, 2021: Expected term (in years) 5.5 - 6.1 Expected volatility 82% - 83% Risk-free interest rate 0.6% - 1.0% Expected dividend yield — The assumptions used in calculating the fair values of purchase rights granted under the ESPP during the six months ended June 30, 2021 are set forth in the table below: Expected term (in years) 0.5 - 2.0 Expected volatility 101% - 119% Risk-free interest rate 0.1 % Expected dividend yield — The Company’s stock-based compensation expense by type of award and by operating expense grouping are presented below: Three Months Ended Six Months Ended June 30, June 30, 2021 2020 2021 2020 Stock-based compensation expense by type of award: Restricted stock units $ 5,579 $ 753 $ 9,750 $ 895 Stock awards — 47 19 109 Performance-based stock options — 1,953 16,314 3,921 Stock options 798 1,306 1,635 3,455 Employee stock purchase plan 101 72 251 207 Common stock issued for services 131 — 250 - Total $ 6,609 $ 4,131 $ 28,219 $ 8,587 Stock-based compensation expense by operating expense grouping: Sales and marketing $ 234 $ 198 $ 1,132 $ 376 Research and development 566 184 1,585 421 General and administrative 5,809 3,749 25,502 7,790 $ 6,609 $ 4,131 $ 28,219 $ 8,587 Equity Award Activity Under Stock Plans Stock Awards The Company’s stock award activity for the six months ended June 30, 2021 was as follows: Weighted Average Grant Shares Date Fair Value Unvested at December 31, 2020 - $ - Granted 581 $ 32.33 Vested (581 ) $ 32.33 Unvested at June 30, 2021 - All stock awards granted during the six months ended June 30, 2021 were fully vested upon grant. As of June 30, 2021, there was no unrecognized compensation cost related to stock awards granted under the Company’s stock plans. Restricted Stock Units The Company’s restricted stock unit activity for the six months ended June 30, 2021 was as follows: Weighted Average Grant Shares Date Fair Value Unvested at December 31, 2020 829,124 $ 11.53 Granted 394,020 $ 44.25 Forfeited (14,439 ) $ 39.60 Vested (749,374 ) $ 10.77 Unvested at June 30, 2021 459,331 $ 39.95 As of June 30, 2021, total unrecognized compensation cost related to restricted stock units was $11,705, which is expected to be recognized over a weighted average period of 0.8 year. Performance-Based Stock Options The activity during the six months ended June 30, 2021 related to stock options that are subject to performance-based vesting conditions tied to the achievement of stock price goals by the Company was as follows: Weighted-Average Remaining Aggregate Exercise Contractual Intrinsic Options Price Term Value Outstanding at December 31, 2020 4,234,020 $ 10.55 Exercised (273,159 ) $ 5.79 Forfeited (12,552 ) $ 5.92 Expired (3,588 ) $ 5.00 Outstanding at June 30, 2021 3,944,721 $ 10.90 7.02 years $ 34,750 Exercisable at June 30, 2021 3,944,721 $ 10.90 7.02 years $ 34,750 During the first six months of 2021, the Company achieved all of the stock price milestones applicable to substantially all of the performance-based stock options and, as a result, such performance-based stock options vested and all associated unrecognized compensation was accelerated and recognized in full as a one-time expense of $16,268 during the six months ended June 30, 2021. The aggregate intrinsic value of the options exercised during the six months ended June 30, 2021 was $6,517. No performance-based stock options were granted during six months ended June 30, 2021 and 2020, and no performance-based stock options vested during the six months ended June 30, 2020. Stock Options The activity during the six months ended June 30, 2021 related to all other stock options was as follows: Weighted-Average Remaining Aggregate Exercise Contractual Intrinsic Options Price Term Value Outstanding at December 31, 2020 5,400,070 $ 12.60 Granted 200,955 $ 33.11 Exercised (348,608 ) $ 8.78 Forfeited (104,774 ) $ 9.79 Expired (2,174 ) $ 5.33 Outstanding at June 30, 2021 5,145,469 $ 13.72 6.55 years $ 34,108 Exercisable at June 30, 2021 4,158,680 $ 13.81 6.05 years $ 24,674 The weighted average grant date fair value of stock options granted during the six months ended June 30, 2021 and 2020 was $23.09 and $2.06 per share, respectively. The aggregate intrinsic value of the stock options exercised during the six months ended June 30, 2021 and 2020 was $8,198 and $177 The aggregate intrinsic values in the tables above represent the difference between the fair market value of the Company’s common stock and the average option exercise price of in-the-money options, multiplied by the number of such stock options. Employee Stock Purchase Plan During the six months ended June 30, 2021, a total of 67,068 shares of common stock were purchased under the Company’s ESPP. As of June 30, 2021, accrued employee contributions for future purchases under the ESPP totaled $223. |