The following table sets forth our statements of operations data expressed as a percentage of total revenue for the periods presented: Three Months Ended  September 30, Nine Months Ended  September 30, 2021 2020 2021 2020 Revenue: Platform 96.5 % 95.2 % 96.5 % 93.6 % Professional services and other 3.5 4.8 3.5 6.4 Total revenue 100.0 100.0 100.0 100.0 Cost of revenue: Platform 17.7 13.0 16.8 15.0 Professional services and other 4.1 4.3 3.6 4.7 Total cost of revenue 21.8 17.4 20.5 19.7 Gross Profit 78.2 82.6 79.5 80.3 Operating expenses: Research and development 38.7 28.6 39.2 33.5 General and administrative 56.9 19.9 48.5 22.3 Sales and marketing 12.6 7.3 11.2 9.0 Total operating expenses 108.3 55.8 98.9 64.7 (Loss) income from operations (30.1) 26.9 (19.3) 15.5 Other expenses, net: Interest expense 0.0 0.0 0.0 (0.2) Other (expense) income, net 0.0 0.0 0.0 0.0 Change in fair value of warrant liability 0.0 (8.1) (17.3) (6.3) Total other expenses, net 0.0 (8.1) (17.3) (6.5) (Loss) income before taxes (30.1) 18.7 (36.6) 9.1 Provision for income taxes 0.1 0.2 0.1 0.2 Net (loss) income and comprehensive (loss) income (30.2) 18.6 (36.7) 8.9 Accretion of redeemable convertible preferred stock to redemption value 0.0 (0.1) 0.0 (0.1) Undeclared 8% dividend on participating securities 0.0 (18.5) 0.0 (8.8) Net loss attributable to Class A and Class B common stockholders (30.2) % 0.0 % (36.8) % 0.0 % (2) Includes charitable donation expense of $8.0 million and $13.1 million for the three and nine months ended September 30, 2021, respectively. 32