For the years ended December 31, 2021 and 2020, cash used in operating activities was $6,805,674 and $2,730,253, respectively. Our cash used in operations for the year ended December 31, 2021 was primarily attributable to our net loss of $11,911,151, adjusted for non-cash expenses in the aggregate amount of $4,670,955, as well as $434,522 of net cash generated from changes in the levels of operating assets and liabilities. Our cash used in operations for the year ended December 31, 2020 was primarily attributable to our net loss of $2,850,096, adjusted for non-cash expenses in the aggregate amount of $864,929, as well as $745,086 of net cash used from changes in the levels of operating assets and liabilities.
For the years ended December 31, 2021 and 2020, cash used in investing activities was $2,737,235 and $46,087, respectively. Cash used in investing activities during the year ended December 31, 2021 was related to deposits paid for equipment of $2,153,950, purchases of property and equipment of 383,285, and the purchase of an intangible asset for $200,000. Cash used in investing activities during the year ended December 31, 2020 was related to the purchases of property and equipment for $46,087.
For the years ended December 31, 2021 and 2020, cash provided by financing activities was $15,526,070 and $11,547,623, respectively. Cash provided by financing activities during the year ended December 31, 2021 was due to proceeds from the exercise of warrants of $11,719,204, proceeds from the sale of Series D Convertible Preferred Stock of $6,500,000, and proceeds from the exercise of options of $121,866. These amounts were partially offset by repayments of notes payable of $2,450,000, and payment of financing costs of $365,000. Cash provided by financing activities during the year ended December 31, 2020 was due to proceeds from the sale of common stock and warrants of $8,000,001, proceeds from notes payable of $3,710,000, proceeds from the sale of common stock issued pursuant to the SEDA agreement of $1,501,696, and proceeds from the Paycheck Protection Program loan of $155,226. These amounts were partially offset by repayments of notes payable of $759,000, payment of offering costs in connection with the sale of common stock and warrants of $705,300, payment of debt issuance costs of $340,000, and payment of financing costs of $15,000.
As of December 31, 2021 and 2020, we had cash balances of $14,863,301 and $8,880,140, respectively, and working capital of $13,302,935 and $6,194,257, respectively. Cash requirements for our current liabilities include approximately, $1,880,113 for accounts payable and accrued expenses (including lease liabilities) and $155,226 related to our PPP loan, for which we will apply for forgiveness. The Company has also committed to spend $1,650,000 in sponsorship fees, capital expenditures of $1,324,251 for automation and testing equipment, and $958,286 for research and development. Cash requirements for long term liabilities consist of $423,447 for lease payments, $350,000 for sponsorship fees, and $245,270 for research and development. The Company intends to meet these cash requirements from its current cash balance and from future revenues.
In March 2020, the World Health Organization declared COVID-19, a novel strain coronavirus, a pandemic. During 2020 and continuing into 2022, the global economy has been, and continues to be, affected by COVID-19. While the Company continues to see signs of economic recovery as certain governments begin to gradually ease restrictions, provide economic stimulus and accelerate vaccine distribution, the rate of recovery on a global basis has been affected by resurgence of the virus or its variants in certain jurisdictions. The Company continues to monitor the impact of COVID-19 on its business and operational assumptions; however, given the uncertainty around the extent and timing of the potential future spread or mitigation of the Coronavirus and around the imposition or relaxation of protective measures, we cannot reasonably estimate the impact to our future results of operations, cash flows, or financial condition.
The short and long-term worldwide implications of Russia’s invasion of Ukraine are difficult to predict at this time. The imposition of sanctions on Russia by the United States or other countries and possible counter sanctions by Russia, and the resulting economic impacts on oil prices and other materials and goods, could affect the price of materials used in the manufacture of our product candidates. If the price of materials used in the manufacturing of our product candidates increase, that would adversely affect our business and the results of our operations.
Our consolidated financial statements included elsewhere in this Annual Report on Form 10-K have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”), which contemplate our continuation as a going concern and the realization of assets and satisfaction of liabilities in the normal course of business. The carrying amounts of assets and liabilities presented in the consolidated financial statements do not necessarily purport to represent realizable or settlement values.
Critical Accounting Estimates
The preparation of financial statements and related disclosures must be in conformity with U.S. GAAP. These accounting principles require us to make estimates and judgments that can affect the reported amounts of assets and liabilities as of the date of the financial statements as well as the reported amounts of revenue and expense during the periods presented. We believe that the estimates and judgments upon which it relies are reasonably based upon information available to us at the time that it makes these estimates and judgments. To the extent that there are material differences between these estimates and actual results, our financial results will be