The increase in reimbursement, general and administrative expenses was partially offset by lower sales and marketing expenses, which decreased $1.0 million, or 6%, to $17.4 million, compared to $18.4 million in the second quarter of 2019 and, to a lesser extent, by lower research and development expenses, which decreased $0.1 million, or 10%, to $1.1 million, compared to $1.2 million in the second quarter of 2019.
Loss from operations in the second quarter of 2020 was $8.0 million, compared to income from operations of $3.0 million in the second quarter of 2019. Excluding the $4.0 million non-cash Airwear inventory write-off and impairment charge in the second quarter of 2020, non-GAAP adjusted loss from operations was $4.0 million, compared to income from operations of $3.0 million in the second quarter of 2019.
Income tax expense in the second quarter of 2020 increased $5.5 million to $5.9 million, compared to $0.4 million in the second quarter of 2019. The increase in income tax expense was primarily due to changes in our effective tax rate, which were attributable to a change in projected taxable income, including proportionately lower benefits for stock-based compensation, as compared to the same period last year.
Net loss in the second quarter of 2020 was $13.9 million, or $(0.72) per diluted share, compared to net income of $2.8 million, or $0.14 per diluted share, in the second quarter of 2019. Weighted average shares used to compute diluted net loss/income per share were 19.3 million and 19.6 million in the second quarters of 2020 and 2019, respectively.
Adjusted EBITDA loss was $0.7 million in the second quarter of 2020, compared to Adjusted EBITDA of $6.3 million in the second quarter of 2019.
First Six Months 2020 Financial Results:
Total revenue for the six months ended June 30, 2020 decreased $4.0 million, or 5%, to $78.8 million, compared to $82.8 million for the six months ended June 30, 2019. Total revenue for the six months ended June 30, 2020 increased 0.2% on an operational basis, excluding the contribution to revenue in the six months ended June 30, 2019 related to the Company’s adoption of ASC 842. The decrease in revenue was driven by a decrease of approximately $5.4 million, or 7%, in sales and rentals of the Flexitouch system, offset partially by an increase of $1.3 million, or 17%, in sales and rentals of the Entre system for the six months ended June 30, 2020. Revenue in the first two months of 2020 was ahead of our expectations. Beginning in March 2020 and continuing throughout the second quarter, revenue was impacted by the COVID-19 pandemic, which disrupted our ability to access our clinician customers and their patients. Specifically, we saw healthcare facilities and clinics restricting access to their clinicians, reducing patient consultations, or closing temporarily due to COVID-19.
Net loss for the six months ended June 30, 2020 was $15.2 million, or $(0.79) per diluted share, compared to net income of $4.3 million, or $0.22 per diluted share, for the six months ended June 30, 2019. Weighted average shares used to compute diluted net loss/income per share were 19.3 million and 19.6 million for the six months ended June 30, 2020 and 2019, respectively.
Adjusted EBITDA loss was $1.2 million in the six months ended June 30, 2020, compared to adjusted EBITDA of $8.4 million in the six months ended June 30, 2019.