Depreciation and Amortization
In the nine-month period ended June 30, 2021, depreciation and amortization increased by $341,095 or 168% from $203,469 for the nine-month period ended June 30, 2020 to $544,564 for the nine-month period ended June 30, 2021. This increase is related primarily to assets purchased to support our COVID-19 surveillance and diagnostic testing, as well the production of our LineaTM COVID-19 Assay Kit.
Interest income (expense), net
Interest (expense) income for the nine-month period ended June 30, 2021, increased to income of $11,975 from expense of $86,811 in the same period of fiscal 2020. The decrease in interest expense was due to the repayment of the July 2019 Notes during October 2020.
Other expense, net
Other expense, net for the nine-month periods ended June 30, 2021 and 2020, was $191,533 and $334,527, respectively. The decrease of $142,994 is due to a decrease in franchise taxes during the nine-month period ended June 30, 2021.
Loss on Extinguishment of Convertible Notes Payable
Loss on extinguishment of convertible notes payable of $1,774,662 for the nine-month period ended June 30, 2021 relates to the repayment of the July 2019 Notes. The loss on extinguishment represents the difference between the fair value of the July 2019 Notes, including the fair value of the Replacement Warrants issued, on the repayment date compared to its carrying value.
Gain on Extinguishment of Notes Payable
Gain on extinguishment of notes payable for the nine-month period ended June 30, 2021 of $839,945 relates to the full forgiveness of the Company’s PPP loan. The gain on extinguishment represents the difference between the fair value of the PPP loan on the forgiveness date compared to their carrying value.
Net Loss Attributable to Common Stockholders
Net loss increased $868,220, or 10% to $9,775,349 for the nine-month period ended June 30, 2021 compared to $8,907,128 for the nine month period ended June 30, 2020 due to the factors noted above.
Liquidity and Capital Resources
Our liquidity needs consist of our working capital requirements and research and development expenditure funding. As of June 30, 2021, we had working capital of $12,121,760. For the nine-month period ended June 30, 2021, we used cash in operating activities of $8,675,878 consisting primarily of our loss of $9,770,855 net with non-cash adjustments of $544,564 in depreciation and amortization charges, $1,631,175 in stock-based compensation expense, $1,774,662 in loss on extinguishment of convertible notes payable, $839,945 gain on extinguishment of notes payable and a provision for bad debts of $6,245. Additionally, we had a net increase in operating assets of $1,783,584 and a net decrease in operating liabilities of $238,140. Cash used in investing activities of $1,642,277 was for the purchase of property and equipment, primarily for the development and implementation of our COVID-19 Surveillance Testing, as well as our LineaTM COVID-19 Assay Kits. Cash provided by financing activities was $14,704,855, which included net proceeds from a registered direct public offering of 13,756,507, warrant exercises of $2,613,929, and the repayment of convertible notes payable of $1,665,581.
We have recurring net losses, which have resulted in an accumulated deficit of $279,610,999 as of June 30, 2021. At June 30, 2021, we had cash and cash equivalents of $12,173,443.