Note 2. Liquidity

On October 23, 2018, the Company sold 7,250,000 shares of the Company’s common stock in an underwritten public offering. The Company granted the underwriters an option to purchase, for a period of 30 calendar days from October 19, 2018, up to an additional 1,087,500 shares of common stock. The Company estimates that the net proceeds from the common stock offering after payment of issuance costs of approximately $2.3 million are approximately $28.5 million, or approximately $32.9 million if the underwriters exercise their over-allotment option in full, in each case, after deducting the underwriting discount and estimated offering expenses payable by the Company.

Additionally, on October 23, 2018 the Company completed an offering of $10.0 million principal amount of the Company’s 6.5% Convertible Senior Secured Notes due 2023. The net proceeds of the offering after payment of offering costs of approximately $1.1 million are approximately $8.9 million.

At September 30, 2018, the Company had cash and cash equivalents of $9.1 million and working capital of $8.4 million. The Company has incurred recurring operating losses, and has experienced net cash used in operating activities of $4.7 million for the three months ended September 30, 2018 which raise substantial doubt about the Company’s ability to continue as a going concern within one year after the issuance date. However, as a result of the convertible note offering and common stock offerings described above, as of October 25, 2018 the Company had $45.9 million of cash and cash equivalents which alleviated any substantial doubt about the Company’s ability to continue as a going concern. These funds will be used to fund the Company’s operations, including capital expenditures, R&D, commercialization of our technology, development of our patent strategy and expansion of our patent portfolio, as well as to provide working capital and funds for other general corporate purposes. These funds are sufficient to fund our operations beyond the next twelve months from the date of filing of this Form 10-Q.