Stock-Based Compensation | Stock-Based Compensation Our equity compensation plans provide for the grant of incentive and nonqualified stock options, as well as other stock-based awards including performance share units (“PSUs”), restricted stock awards (“RSAs”), restricted stock units (“RSUs”), and deferred stock units (“DSUs”), to employees, non-employee directors and other consultants who provide services to us. We also provide an employee stock purchase plan (“ESPP”) and 401(k) match to eligible participants. We recognize stock-based compensation expense based on grant date award fair value. This cost is recognized over the period for which the employee is required to provide service in exchange for the award or the award performance period, except for expenses relating to retirement-eligible employees that have not given their required notice, which is recognized on a pro-rata basis over the notice period prior to retirement. At September 30, 2023 , there were 12.8 million shares available for grant under approved equity compensation plans. Stock-based compensation expense was allocated in the condensed consolidated statements of comprehensive income as follows: Three Months Ended Nine Months Ended (in thousands) 2023 2022 2023 2022 Cost of revenues $ 2,506 $ 2,146 $ 7,595 $ 6,477 Operating expenses Sales and marketing 2,428 1,845 7,379 5,835 Research and development 1,798 1,396 5,387 4,250 General and administrative 4,704 2,573 15,736 9,074 $ 11,436 $ 7,960 $ 36,097 $ 25,636 Stock-based compensation expense by grant type or plan was as follows: Three Months Ended Nine Months Ended (in thousands) 2023 2022 2023 2022 Stock options $ 487 $ 461 $ 1,472 $ 1,401 PSUs 2,812 1,541 10,236 6,244 RSUs & DSUs 6,722 4,735 20,165 14,467 RSAs 122 110 345 328 ESPP 637 577 1,974 1,609 401(k) stock match 656 536 1,905 1,587 $ 11,436 $ 7,960 $ 36,097 $ 25,636 As of September 30, 2023, there was $50.3 million of unrecognized stock-based compensation expense under our equity compensation plans, which is expected to be recognized on a primarily straight-line basis over a weighted average period of 2.4 years. Stock Options Our stock option activity was as follows: Nine Months Ended Options (#) Weighted Average Outstanding, beginning of period 562,697 $ 56.24 Granted 39,949 152.08 Exercised (154,279) 35.80 Forfeited (2,236) 127.39 Outstanding, end of period 446,131 $ 71.54 Of the total outstanding options at September 30, 2023, 0.4 million were exercisable. The outstanding and exercisable options had a weighted average exercise price of $59.61 per share and a weighted average remaining contractual life of 2.9 years. The weighted average grant date fair value of options granted during the nine months ended September 30, 2023 was $56.29 per share. This was estimated on the date of grant using the Black-Scholes option pricing model with the following weighted-average assumptions: Life (in years) 4.2 Volatility 39.3 % Dividend yield — Risk-free interest rate 4.0 % Performance Share Units, Restricted Stock Units and Awards, and Deferred Stock Units In each of the quarters ended March 31, 2023, 2022, 2021, and 2020 we granted PSU awards with a target performance level. These awards are earned based upon our Company’s total shareholder return as compared to an indexed total shareholder return over the course of a fiscal based three-year performance period, starting in the year of grant. Earned awards vest in the quarter following the conclusion of the performance period. In the three months ended March 31, 2023 , PSU awards granted in 2020 vested at the maximum performance level and 0.1 million shares of common stock were issued. Activity for our PSUs, RSUs, RSAs, and DSUs in aggregate was as follows: Nine Months Ended # Weighted Average Grant Outstanding, beginning of period 712,158 $ 103.93 Granted 352,457 163.26 Vested and common stock issued (341,570) 77.06 Forfeited (7,607) 118.37 Outstanding, end of period 715,438 $ 145.83 The number of PSUs, RSUs, RSAs, and DSUs outstanding at September 30, 2023 included 0.1 million units that have vested, but the shares of common stock have not yet been issued, pursuant to the terms of the underlying agreements. Employee Stock Purchase Plan Our ESPP activity was as follows: Three Months Ended Nine Months Ended (in thousands, except shares) 2023 2022 2023 2022 Amounts for shares purchased $ 344 $ 238 $ 4,481 $ 3,588 Shares purchased 3,159 2,481 41,384 37,516 A total of 1.7 million shares of common stock are reserved for issuance under the ESPP as of September 30, 2023. The fair value was estimated based on the market price of our common stock at the beginning of the offering period using the following assumptions: Life (in years) 0.5 Volatility 40.1 % Dividend yield — Risk-free interest rate 4.6 % |