and cash equivalents held in U.S. dollars and euros resulting from the proceeds from the issuance of common and preferred stock as well as payments received under our Gilead and Roche collaborations. During the three months ended March 31, 2024 our cash, cash equivalents and restricted cash were mainly held in dollars at U.S. investment grade financial institutions or in money market funds. In addition, smaller amounts were held in euros and dollars at our Austrian subsidiary.
Interest expenses for loans from government agencies were less than $0.1 million for the three months ended March 31, 2024, compared to $0.1 million for the three months ended March 31, 2023. Interest expense was recorded at the market rate of interest, which exceeded the contractual interest rate.
Other Income and Expenses
Other expenses were $0.3 million for the three months ended March 31, 2024, compared to $0.2 million for the three months ended March 31, 2023. The change in the three months ended March 31, 2024 resulted primarily from exchange rate differences and foreign currency remeasurements.
Liquidity and Capital Resources
Since our inception in 2011, we have funded our operations primarily from public offerings and private placements of common stock and convertible preferred stock, including our initial public offering, as well as private placements of our redeemable convertible preferred stock, grant funding and loans from an Austrian government agency, and upfront, milestone and initiation payments from Gilead and Roche in connection with research collaboration agreements.
Prior to our IPO, we raised gross proceeds of approximately $142.5 million from the issuance of our redeemable convertible preferred stock. In April 2019, we completed our IPO in which we issued and sold 6,000,000 shares of our common stock, at $14.00 per share, for gross proceeds of $84.0 million, or net proceeds of $74.6 million. In December 2020, we completed a follow-on public offering in which we issued 3,910,000 shares of our common stock, at $11.75 per share, and 2,978 shares of our Series A convertible preferred stock, at $11,750.00 per share, for net proceeds of $75.0 million after deducting underwriting discounts and commissions and offering expenses. In March 2022, we completed a follow-on public offering in which we issued 21,700,000 shares of our common stock, at $2.00 per share, and 15,800 shares of our Series A-1 convertible preferred stock, at $2,000.00 per share, for net proceeds of $70.2 million after deducting underwriting discounts and commissions and offering expenses. In June 2023, we completed a follow-on public offering in which we issued 22,900,768 shares of our common stock, at $1.31 per share, and 15,268 shares of our Series A-2 convertible preferred stock, at $1,310.00 per share, for net proceeds of $46.2 million after deducting underwriting discounts and commissions and offering expenses. In addition, in February 2022, Gilead purchased 1,666,666 shares of our common stock for $5.0 million, at a purchase price of $3.00 per share, and in December 2023, Gilead purchased 15,000,000 shares of our common stock, at $1.4167 per share, for net proceeds of approximately $21.1 million after deducting offering expenses. Pursuant to the terms of the Amended Stock Purchase Agreement, we may require Gilead to purchase the balance of the $8.75 million of common stock as pro-rata participation in potential future equity raises (see “Note 10. Common stock, Class A common stock and convertible preferred stock” to our consolidated financial statements appearing elsewhere in this Quarterly Report). We also received $46.2 million from non-refundable upfront, milestone and initiation payments pursuant to the Restated Gilead Collaboration Agreement and $35.0 million from non-refundable upfront and milestone payments related to the Roche Collaboration Agreement. In the second quarter of 2024 we received a $10.0 million milestone payment related to the Roche collaboration. As of March 31, 2024, we had cash, cash equivalents and restricted cash of $93.0 million.
On July 12, 2022, we filed a registration statement on Form S-3 (the “Registration Statement”), with the SEC, which was declared effective on July 21, 2022. The Registration Statement registers the offering, issuance and sale of an unspecified amount of common stock, preferred stock, debt securities, warrants and/or units of any combination thereof. We simultaneously entered into a Sales Agreement with SVB Securities LLC, as sales agent, to provide for the issuance and sale by us of up to $50.0 million of common stock from time to time in “at-the-market” offerings under the Registration Statement and related prospectus filed with the Registration Statement, or the ATM Program. As of March 31, 2024, no sales had been made pursuant to the ATM Program.