General and Administrative
For the three months ended September 30, 2021, general and administrative expense increased $0.1 million, or 2.5 percent, to $2.3 million from $2.2 million for the same period last year. This increase is primarily due to higher payroll and benefits expenses, partially offset by lower stock compensation expense.
For the nine months ended September 30, 2021, general and administrative expense decreased $(2.9) million, or (28.0) percent, to $7.2 million from $10.1 million for the same period last year. This decrease is primarily due to stock and cash compensation expenses incurred during the nine months ended September 30, 2020 related to the separation of our former Chief Executive Officer, partially offset by higher regulatory affairs expenses.
Sales and Marketing
For the three months ended September 30, 2021, sales and marketing expense increased $0.3 million, 13.3 percent, to $2.6 million from $2.3 million for the same period last year. This increase is primarily due to higher sales commissions and sales activities expenses, partially offset by lower payroll and benefits expenses.
For the nine months ended September 30, 2021, sales and marketing expense increased $0.3 million, 4.9 percent, to $7.4 million from $7.1 million for the same period last year. This increase is primarily due to higher sales commissions and sales activities expenses, partially offset by lower payroll and benefits expenses.
Research and Development
For the three months ended September 30, 2021, research and development expense was consistent at $0.5 million. For the nine months ended September 30, 2021, research and development expense was consistent at $1.4 million. There were no significant changes in these accounts during the three and nine months ended September 30, 2021, compared to the same periods last year.
Other Income, Net
Other income, net consists of interest income, foreign currency gains and losses, and other miscellaneous income. For the three months ended September 30, 2021, we reported other income of approximately $7,000, compared to $9,000 for the three months ended September 30, 2020. There were no significant changes in these accounts during the three months ended September 30, 2021, compared to the same quarter last year.
For the nine months ended September 30, 2021, we reported other income of approximately $15,000, compared to $126,000 for the nine months ended September 30, 2020. This decrease is primarily due to lower interest income during the nine months ended September 30, 2021.
Income Taxes
For the three and nine months ended September 30, 2021, we recorded a provision for income tax expense of $517,767 and $1,289,988, respectively. Our effective tax rate was 16.7 percent and 19.2 percent, respectively, and differed from the U.S. Federal statutory rate primarily due to benefits from foreign derived intangible income, stock compensation and research and development tax credits, partially offset by U.S. state income tax expense.
For the three and nine months ended September 30, 2020, we recorded a provision for income tax benefit of $(280,536) and $(2,012,998), respectively. Our effective tax rate was (35.3) percent and 157.1 percent, respectively, and differed from the U.S. Federal statutory rate primarily due to discrete items related to tax benefits associated with stock-based compensation and a U.S. state tax benefit, partially offset by a limitation on the deductibility of certain executive compensation associated with the separation of our former Chief Executive Officer. Additionally, we recognized a benefit in our effective tax rate resulting from the Coronavirus Aid, Relief, and Economic Security Act, which allowed us to carryback net operating losses to years prior to the enactment of the Tax Cuts and Jobs Act.