8. Long-Term Debt

On November 6, 2024 (the "Closing Date"), the Company entered into a Loan and Security Agreement (the “Hercules Loan Agreement”), with the lenders party thereto (the “Lenders”) and Hercules Capital, Inc., as administrative agent and collateral agent (the “Agent”). The Hercules Loan Agreement provides for up to $200.0 million of senior secured term loans available to the Company in multiple tranches (the “Term Loan Facility”). Under the Hercules Loan Agreement, the Company borrowed an initial amount of $30.0 million on the Closing Date, and at the Company's sole option, can draw an additional $80.0 million on or prior to December 15, 2026, as well as additional term loan advances in an aggregate principal amount of up to $65.0 million during the term of the Term Loan Facility subject to achievement of specified performance milestones, and one additional term loan advance up to an aggregate principal amount of $25.0 million subject to certain terms and conditions. The Company intends to use the proceeds of the Term Loan Facility for working capital and general corporate purposes.

The Term Loan Facility will mature on December 1, 2029 (the “Maturity Date”). The outstanding principal balance of the Term Loan Facility bears cash interest at a floating annual rate equal to the greater of (i) 8.25% and (ii) the sum of the Prime Rate and 1.75%. Accrued interest is payable monthly following the funding of each term loan advance. Borrowings under the Hercules Loan Agreement are repayable in monthly interest-only payments through November 2028. At the end of the interest-only payment period, borrowings under the Hercules Loan Agreement are repayable in equal monthly payments of principal and accrued interest until the Maturity Date. At the Company's option, the Company may prepay all or a portion of the outstanding borrowings, subject to a prepayment fee of 3.0% of the principal amount if prepayment occurs during the 18 months following the Closing Date, 2.0% after 18 months following the Closing Date but prior to 36 months following the Closing Date, and 1.0% thereafter.

The obligations under the Hercules Loan Agreement are secured, subject to customary permitted liens and other agreed-upon exceptions, by a first-priority perfected security interest in all of the tangible and intangible assets of the Company, other than intellectual property. The Hercules Loan Agreement includes customary repayment and prepayment terms, events of default, affirmative and negative covenants and representations and warranties. Additionally, the Hercules Loan Agreement contains a minimum cash covenant that requires the Company to maintain certain levels of cash in accounts subject to a control agreement in favor of the Agent at all times beginning on the first day on or after January 1, 2027 (or January 1, 2028, if the Company achieves a certain milestone) on which the aggregate principal amount of the term loan advances is then more than $50.0 million; provided, however, the minimum cash covenant will be waived during all times that the Company's market capitalization is greater than or equal to $1.0 billion. The Hercules Loan Agreement also includes a subjective acceleration clause for circumstances which could be reasonably expected to have a material adverse effect on the Company.

The Hercules Loan Agreement provides for a final payment ("End of Term Charge"), payable upon maturity or the repayment of the obligations in full or in part (on a pro rata basis), equal to 6.75% of the aggregate principal amount of term loans advanced to the Company and repaid on such date, which is being accrued on the Company's condensed consolidated balance sheets.

The Company recorded debt discount and debt issuance costs of $1.8 million upon closing of the Hercules Loan Agreement. Debt discount and unamortized debt issuance costs were recorded as a reduction of the carrying amount on the term loan and are amortized as interest expense using the effective-interest method. In addition, unamortized deferred financing costs of $0.6 million were recorded in other assets as of June 30, 2025, related to the Company's right to borrow additional amounts in the future.

Interest expense for the three and six months ended June 30, 2025 was $0.9 million and $1.8 million, respectively. As of June 30, 2025, the carrying value of the Term Loan Facility approximates its fair value.

The table of future principal payments excludes the End of Term Charge of $2.0 million, which is due upon the maturity of the loan.