For the nine months ended September 30, 2020, general and administrative expense increased $2.6 million, or 34.5 percent, to $10.1 million from $7.5 million for the same period last year. This increase is primarily due to higher expenses from stock and cash compensation related to the separation of our former Chief Executive Officer, higher payroll and benefits costs related to higher headcount, partially offset by lower legal and professional expenses. During the nine months ended September 30, 2020, the Company recognized total general and administrative expense of $3.2 million related to our former Chief Executive Officer, of which $2.7 million relates to the separation.
Sales and Marketing
For the three months ended September 30, 2020 and 2019, sales and marketing expense was consistent at $2.3 million. For the three months ended September 30, 2020, sales and marketing expense was 29.6 percent of revenue compared to 23.1 percent for the same period in 2019. This is primarily the result of higher payroll and employee benefits costs higher sales commissions expense, offset by lower sales activities expenses.
For the nine months ended September 30, 2020, sales and marketing expense increased $0.5 million, or 7.3 percent, to $7.1 million from $6.6 million for the same period last year. This increase is primarily the result of higher payroll and employee benefits costs and higher sales commissions, partially offset by lower sales activities expenses.
Research and Development
For the three months ended September 30, 2020, research and development expense increased $0.1 million, or 29.1 percent, to $0.5 million from $0.4 million for the same period last year. This increase is primarily the result of higher payroll and employee benefits costs due to increased headcount, partially offset by lower consulting expenses.
For the nine months ended September 30, 2020 and 2019, research and development expense increased $0.3 million, or 31.9 percent, to $1.4 million from $1.1 million for the same period last year. This increase is primarily the result of higher payroll and employee benefits expenses due to increased headcount and higher employee recruiting expenses, partially offset by lower consulting expenses.
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, 2020 and 2019, we reported other income of approximately $9,000 and $110,000, respectively. This decrease is primarily due to lower interest income.
For the nine months ended September 30, 2020 and 2019, we reported other income of approximately $126,000 and $281,000, respectively. This decrease is primarily due to lower interest income.
Income Taxes
For the three and nine months ended September 30, 2020, we recorded a provision for income tax benefit of $(0.3) million and $(2.0) million, 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.
For the three and nine months ended September 30, 2019, we recorded a provision for income tax expense of $0.2 million and $0.3 million, respectively. Our effective tax rate was 6.6 percent and 4.5 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 the foreign derived intangible income deduction, partially offset by U.S. state tax expense.
As of September 30, 2020, and December 31, 2019, we had not identified or accrued for any uncertain tax positions. We are currently unaware of any uncertain tax positions that could result in significant payments, accruals or other material deviations in this estimate over the next 12 months. We believe that our tax positions comply in all material respects with applicable tax law. However,