approximately $81,000 decrease in lease liability, offset by an approximately $280,000 increase in accounts payable, an approximately $259,000 decrease in accounts receivable-unbilled, an approximately $82,000 decrease in operating lease right-of-use asset, and an approximately $55,000 decrease in prepaid expenses and other current assets.
For the six months ended June 30, 2023, net cash used in operating activities was approximately $4,519,000, which consisted of a net loss of approximately $5,915,000 offset by non-cash charges of approximately $1,420,000, which included approximately $935,000 related to amortization of internally developed software, approximately $262,000 in bad debt expense, approximately $245,000 in stock-based compensation, and approximately $76,000 related to depreciation of property and equipment, offset by $98,000 of amortization of discount on available-for-sale securities.
Total changes in assets and liabilities of approximately $23,000 were attributable to an approximately $679,000 decrease in accounts payable, an approximately $649,000 decrease in accrued expenses, an approximately $123,000 increase in accounts receivable, an approximately $78,000 decrease in operating lease liability, and an approximately $43,000 decrease in deferred revenue, offset by an approximately $1,229,000 decrease in accounts receivable-unbilled, an approximately $129,000 decrease in tax credit receivable, an approximately $113,000 decrease in prepaid expenses and other current assets, and an approximately $78,000 decrease in operating lease right-of-use asset.
Investing Activities
Net cash provided by investing activities was approximately $2,233,000 for the six months ended June 30, 2024, which consisted of approximately $3,150,000 of proceeds from sales and maturities of available-for-sale securities, which were offset by approximately $461,000 of purchases of available-for-sale securities, approximately $448,000 of capitalization of internally developed software, and approximately $9,000 of purchase of property and equipment.
Net cash used in investing activities was approximately $8,856,000 for the six months ended June 30, 2023, which consisted of approximately $7,643,000 of purchase of available-for-sale securities, approximately $2,732,000 of capitalization of internally developed software, and approximately $14,000 of purchase of property and equipment, offset by approximately $1,532,000 of proceeds from sale and maturities of available-for-sale securities.
Financing Activities
Net cash provided by financing activities was approximately $1,187,000 for the six months ended June 30, 2024, which consisted of approximately $1,494,000 of proceeds received from the issuance of common stock in connection with the ATM Offering, offset by approximately $255,000 for the payment of offering costs in connection with the issuance of common stock in connection with the ATM Offering and approximately $53,000 for the repurchase of common stock exercisable under PIPE Warrants.
Net cash provided by financing activities was approximately $71,000 for the six months ended June 30, 2023, due to proceeds received from the exercise of stock options.
Effects of Inflation and Supply Chain Shortages
Our operations are heavily reliant on specimen availability, and as a result, we often receive more requests than we can fulfill. While the Company is subject to these types of supply chain constraints that are specific to the specimen industry, we have not been materially affected by the more common supply chain issues currently affecting the economy, specifically surrounding transportation. Due to the small size of the packages that we ship, our carriers were able to continue making timely deliveries during the six months ended June 30, 2024. However, there had been an increase in our shipping costs period over period during the six months ended June 30, 2024.
We have experienced negative effects of inflation in certain areas of our business due to the high rates of inflation in the world’s current economy. This inflation is affecting employee salaries, which account for a significant portion of our operating costs. Additionally, the costs of supplies have been affected by inflation; however, these costs are not significant to the Company’s results.
Inflation has not had a significant impact on the cost of specimens due to our long-term contracts maintained with vendors, which include revenue sharing plans.