slowed patient enrollment and caused delays in the Company’s clinical trials and issuance of results. Any rise of COVID-19 infection rates, especially in the United States, could continue to negatively affect enrollment going forward. We continue to closely monitor the COVID-19 situation and any potential impact to our planned activities.
Financial Overview
Since commencing operations in 2015, we have devoted substantially all our efforts and financial resources to organizing and staffing our company, identifying business development opportunities, raising capital, securing intellectual property rights related to our product candidates, building and optimizing our manufacturing capabilities, and conducting discovery, research and development activities for our product candidates, discovery programs and FIND-IO platform.
We have not generated any revenue from product sales and only limited revenue from other sources. Our net loss for the three months ended June 30, 2022 and 2021, was $17.9 million and $18.0 million, respectively, and our net loss for the six months ended June 30, 2022 and 2021, was $38.5 million and $34.5 million, respectively. As of June 30, 2022, we had an accumulated deficit of $225.5 million, primarily as a result of research and development and general and administrative expenses. We do not expect to generate product revenue unless and until we obtain marketing approval and commercialize a product candidate, and we cannot assure you that we will ever generate significant revenue or profits.
We have funded our operations to date primarily with proceeds from public offerings of our common stock, with private placements of our preferred stock and with upfront fees received under our former research and development collaboration agreement with Lilly, or the “Lilly Agreement,” which was terminated in March 2020. From our inception through June 30, 2022, we received gross proceeds of $164.4 million through private placements of preferred stock.
In November 2018, we entered into the Lilly Agreement to use our FIND-IO platform to identify novel oncology targets for additional collaborative research and drug discovery by us and Lilly. We received an upfront payment of $25.0 million in cash and an equity investment of $15.0 million from Lilly upon entering into the Lilly Agreement. We were also eligible for quarterly research and development support payments during a portion of the term of the Lilly Agreement. Effective March 3, 2020, Lilly terminated the Lilly Agreement without cause.
On May 13, 2019, we closed our initial public offering, or “IPO”, in which we sold 5,750,000 shares of common stock at a public offering price of $15.00 per share, for aggregate gross proceeds of $86.3 million. The net offering proceeds to us were approximately $77.0 million after deducting underwriting discounts and commissions of $6.0 million and offering expenses of $3.4 million.
On November 19, 2019, we completed an underwritten public offering, in which we issued and sold 4,077,192 shares of common stock at a public offering price of $36.75 per share. On December 2, 2019, the underwriters exercised in full their option to purchase an additional 611,578 shares of common stock at the public offering price of $36.75, for total net proceeds to us of approximately $160.9 million, after deducting underwriting discounts and commissions of approximately $10.3 million and offering expenses of approximately $1.0 million.
As of June 30, 2022, we had cash, cash equivalents and marketable securities, excluding restricted cash, of $185.5 million. We believe that our existing cash, cash equivalents and marketable securities will be sufficient to fund our planned operations into the first quarter of 2024. We have based this estimate on assumptions that may prove to be incorrect, and we could use our available capital resources sooner than we currently expect.
We expect to incur substantial expenditures in the foreseeable future as we advance our product candidates through clinical development, the regulatory approval process and, if approved, commercialization, and as we expand our pipeline through research and development activities related to our FIND-IO platform and discovery programs. Specifically, in the near term, we expect to incur substantial expenses relating to our ongoing Phase 1/2 clinical trial and planned Phase 2 clinical trial of NC318, our ongoing Phase 1/2 clinical trial of NC410, and our ongoing Phase 1/2 clinical trial for NC762, and other research and development activities. We expect to continue to incur significantly increased costs as a result of operating as a public company, including significant legal, accounting, investor relations and other expenses that we did not incur as a private company.