We do not allocate personnel-related costs, including stock-based compensation costs, or other indirect costs to specific programs, as they are deployed across multiple projects under development and discovery and, as such, are separately classified as internal research and development expenses in the table above.
Research and development expenses for the three months ended March 31, 2023 decreased $3.4 million, or 22.5% compared to the three months ended March 31, 2022, as lower external research and development expenses were partially offset by higher internal research and development expenses, primarily higher personnel costs. The lower external research and development costs were largely attributable to the decision to discontinue clinical development of NC318 announced in the fourth quarter of 2022 and lower costs associated with NC525, as this program initiated a phase 1 trial in February 2023.
General and Administrative Expenses
General and administrative expenses for the three months ended March 31, 2023 decreased by $0.3 million compared to the three months ended March 31, 2022. The decrease was primarily due to lower stock compensation expense and lower professional services expenses.
Other Income, Net
Other income, net for the three months ended March 31, 2023 increased by $0.8 million compared to the three months ended March 31, 2022, due to higher interest income as a result of higher interest rates on our investments.
Liquidity and Capital Resources
We have financed our operations primarily with proceeds from public offerings of our common stock, private placements of our preferred stock and upfront fees received under the the Company’s former agreement with Eli Lilly and Company, which was terminated in March 2020 (the “Lilly Agreement”). On May 13, 2019, we closed our IPO, in which we sold 5,750,000 shares of common stock at a public offering price of $15.00 per share, for net offering proceeds to us of approximately $77.0 million after deducting underwriting discounts and commissions and offering expenses. On November 19, 2019, we completed an underwritten public offering in which we 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 a public offering price of $36.75. Net offering proceeds to us were approximately $160.9 million after deducting underwriting discounts and commissions and offering expenses. Since inception, we have received aggregate gross proceeds of $164.4 million from the sale and issuance of shares of our preferred stock. In addition, in November 2018, we received an upfront payment of $25.0 million in cash from Lilly pursuant to the Lilly Agreement. Our cash and cash equivalents are held in money market funds.
On May 6, 2021, the Company entered into a sales agreement (the “Sales Agreement”) with SVB Leerink LLC (the “Agent”), pursuant to which the Company may sell, from time to time, up to an aggregate sales price of $75 million of its common stock through the Agent in negotiated transactions that are deemed to be an “at the market offering.” The Agent will be entitled to compensation equal to 3.0% of the gross proceeds from the sale of all shares of common stock sold through it as Agent under the Sales Agreement. Actual sales will depend on a variety of factors to be determined by the Company from time to time, including, among other things, market conditions, the trading price of the common stock, capital needs and determinations by the Company of the appropriate sources of funding for the Company. We have not yet sold any shares of our common stock pursuant to the Sales Agreement.
As of March 31, 2023, we had cash, cash equivalents and marketable securities of $145.5 million. We believe that our existing cash, cash equivalents and marketable securities will be sufficient to fund our planned operations into mid-2025.
We will continue to require additional capital to develop our product candidates and fund operations for the foreseeable future. We may seek to raise capital through sale of equity, debt financings, strategic alliances and licensing arrangements. Adequate additional funding may not be available to us on acceptable terms or at all. If we fail to raise