10. Notes Payable, net

PWB Term Loan

In August 2020, the Company entered into a loan agreement (the "PWB Loan Agreement") with a lender, Pacific Western Bank, and received a loan in the principal amount of $2,000 (the "PWB Term Loan") that bore interest on the outstanding daily balance at a rate equal to the greater of: (a) 0.50% above the variable rate of interest announced by the lender as its “prime rate” then in effect; or (b) 4.50%. The PWB Loan Agreement created a first priority security interest with respect to substantially all assets of the Company, including proceeds of intellectual property, but expressly excluding intellectual property itself.

The Company was required to pay accrued interest on the current loan on the 13th day of each month through and including August 13, 2023, at which time the unpaid principal and accrued and unpaid interest was due and payable in full. On August 17, 2023, the Company entered into an amendment to the PWB Loan Agreement extending the maturity date to August 13, 2026 with interest only payments until such date, having daily borrowings bearing interest at a variable annual rate equal to the greater of the Lender's "prime rate" then in effect and 4.50%, and cause the Company to maintain all of its depository, operating, and investment accounts with Pacific Western Bank. The Company determined this amendment constituted a loan modification under ASC 470, and used the updated imputed interest rate to recalculate debt discounts, debt issuance costs and final payment to be amortized over the new term.

The PWB Loan Agreement contains a liquidity covenant, which requires that the Company maintain cash in accounts of the lender or subject to control agreements in favor of the lender in an amount equal to at least the outstanding balance of the PWB Term Loan, which was $2,000 as of December 31, 2023. It also contains a primary depository covenant, which restricts the Company from having more than $1,000 held in subsidiary accounts outside of the United States. As of December 31, 2023 the Company was compliant with all covenants.

The interest rate of the PWB Term Loan is subject to increase in the event of late payment and after occurrence of and during the continuation of an event of default. The Company may elect to prepay the PWB Term Loan at any time, in whole or in part, without penalty or premium.

The debt issuance costs and debt discounts combined with the stated interest resulted in an effective interest rate of 8.81% for the year ended December 31, 2023. The debt issuance costs will be amortized to interest expense using the effective interest method over the life of the loan. Interest expense for the PWB Term Loan totaled $173 and $119 for the years ended December 31, 2023 and 2022, respectively.

The following table presents scheduled principal payments of the Company's PWB term loan as of December 31, 2023:

Parker Hannifin Promissory Note

In connection with the HMC Acquisition, on December 5, 2022, the Company delivered a $5,000 unsecured, subordinated promissory note (the "Promissory Note") to Parker. The Promissory Note, subordinate to the PWB Term Loan, bears no interest with principal payable in sixteen equal installments due on the last day of each quarter, which commenced on December 31, 2023 and matures on September 30, 2027. For additional information see Note 4.

The Promissory Note, upon the occurrence of an event of default, allows for the levying of interest equal to the lesser of (a) 5% per annum and (b) the maximum interest rate permitted under applicable law on the then entire outstanding principal balance, and also for the acceleration of all outstanding liabilities and obligations, making them immediately payable. Under the terms of the Promissory Note, the following occurrences constitute a default, and could, upon written notice or declaration by Parker, allow for the levying of interest and or the acceleration of principal outstanding: (i) failure to pay any amount of the principal when due and payable, (ii) the dissolution of the Company (including the declaration of bankruptcy), and (iii) the acquisition of the Company by another entity or the sale of substantially all of its assets to another entity.

The Company recorded the Promissory Note of $4,055 in its consolidated balance sheets under the captions Notes payable, current and Notes payable, net, estimating an implicit discount rate of 7.5% via reference to the interest charged on the Company's PWB Term Loan and other relevant economic factors present at the execution date of the Promissory Note. The amortization of debt discounts resulted in an effective interest rate of 7.18% for the year ended December 31, 2023. The debt discount is amortized to interest expense using the effective interest method over the life of the loan. Interest expense on the Promissory Note was $320 and $25 for the year ended December 31, 2023 and 2022, respectively.

The following table presents scheduled principal payments of the Promissory Note as of December 31, 2023: