During the year ended December 31, 2020, we used $13,964,053 of cash for operating activities as compared to $22,355,020 for the comparable period in 2019. For the year ended December 31, 2020 we incurred a net loss of $17,952,172, partially offset by non-cash operating expenses of $5,489,119, for a net cash loss of $12,436,288. Net changes in working capital items were $1,527,765 for 2020 with the largest factor resulting from $1,936,050 of investments in inventory and vendor prepayments for M400 components; partially offset by an increase in trade payables of $454,370.
For the year ended December 31, 2020, net loss after adding back non-cash operating expenses, such as depreciation and amortization, stock-based compensation, inventory reserve for obsolescence and net gain on debt extinguishment, was $12,463,053 versus $17,863,773 in the same period of 2019.
During the year ended December 31, 2020, we used $1,485,513 of cash for investing activities, which includes $496,629 for purchases of manufacturing equipment and product mold tooling, $500,000 in the purchase of software operating system license upgrades for our smart glasses platform, and $488,884 of investments in patents and trademarks. For the year ended December 31, 2019, we used a total of $3,157,539 in cash for investing activities.
During the year ended December 31, 2020, we received $40,912,983 in cash from financing activities, which included: (i) $10,582,309 in net proceeds from our sale of equity securities that closed on May 13, 2020, (ii) $1,555,900 in proceeds from the term loan obtained under the Payroll Protection Act, (iii) $14,617,027 in net proceeds from our sale of equity securities that closed on September 9, 2020, (iv) $14,128,527 in proceeds from the exercise of warrants, and (v) $29,220 in proceeds from the exercise of stock options. For the year ended December 31, 2019, we received $18,855,007 from financing activities.
As of December 31, 2020, the Company does not have any current or long-term debt obligations outstanding.
We incurred a net loss for the year ended December 31, 2020 of $17,952,172 and annual net losses of $26,476,370 in 2019 and $21,875,713 in 2018. The Company has an accumulated deficit of $162,694,983 as of December 31, 2020.
The Company’s cash requirements are primarily for funding operating losses, working capital, research and development, and capital expenditures. Our operations are financed primarily through the net proceeds from the sale of our equity securities and the exercise of any related warrants. As of December 31, 2020, our principal sources of liquidity consisted of cash and cash equivalents of $36,069,508.
On January 28, 2021, the sole holder converted all of its 49,626 shares of Series A Preferred Stock into 4,962,600 shares of common stock and the shares of Series A Preferred Stock have been retired and cannot be reissued. The Company and holder also entered into an agreement on the conversion date pursuant to which the holder agreed to accept $10,000,000 in full payment of all accrued Series A Preferred Share dividends in the approximate amount of $10,800,000.
Since December 31, 2020, a total of 7,196,378 warrants were exercised on a cash basis resulting in the issuance of 7,196,378 shares of common stock in exchange for proceeds of $34,352,848. This has increased our cash and cash equivalents after the payment preferred dividend payment, to a pro-forma total of $60,422,356 before ongoing operating losses and capital investments since December 31, 2021.
The Company needs to grow its business significantly to become profitable and self-sustaining on a cash flow basis or it will be required to raise new capital. Our cash requirements related to funding operating losses depend on numerous factors, including new product development activities, our ability to commercialize our products, our products’ timely market acceptance, selling prices and gross margins, and other factors.
We believe our existing cash and cash equivalent balances will be sufficient to meet our long-term working capital and capital expenditure needs for at least the next 12 months. We intend to increase our levels of investing activities for our 2021 fiscal year as compared to 2020, primarily on new product development as well as increase our R&D spending over that of 2020. Our future capital requirements may vary materially from those currently planned and