The primary factors that impact our cost of revenue are manufacturing efficiencies, cost of material, and mix of products. Given our advanced investment in capacity to capture future demand, we expect to continue to incur significant fixed costs that will be amortized over larger volumes of production as we scale our business.
Research and Development Expenses
Research and development expenses consist primarily of costs related to research, design, maintenance, and minor enhancements of our software that are expensed as incurred. Research and development expenses consist primarily of costs incurred for salaries and related personnel expenses, including stock-based compensation expense, for personnel related to the development of improvements and expanded features for our products, materials and supplies used in development and testing, payments to consultants, outside manufacturers, patent related legal costs, facility costs and depreciation. We expect that our research and development expenses will increase in absolute dollars as our business grows, particularly as we incur additional costs related to continued investments in development of new products and offerings. However, we expect that our research and development expenses will decrease as a percentage of our revenue over time.
Selling, General and Administrative Expenses
Selling, general, and administrative expenses consist primarily of salaries and related personnel expenses, including stock-based compensation, related to sales and marketing, finance, legal and human resource functions, contractor and professional services fees, audit and compliance expenses, insurance costs, advertising and promotional expenses and general corporate expenses, including allocated facilities and information technology expenses.
We expect our selling, general, and administrative expenses to increase in absolute dollars for the foreseeable future as we scale headcount with the growth of our business, and as a result of operating as a public company, including compliance with the rules and regulations of the SEC and Nasdaq, legal, audit, higher expenses for directors and officer insurance, investor relations activities, and other administrative and professional services. Over time, we expect our selling, general and administrative expenses to decline as a percentage of revenue.
Interest and Other Income (Expense), net
Interest and other income (expense), net comprises interest income, interest expense, other expense, net, gain or loss arising out of change in fair value of sponsor earn-out liability, redeemable convertible preferred stock warrants and other derivative liabilities.
Interest income consists primarily of interest received or earned on our cash and cash equivalents balances.
Interest expense consists primarily of interest incurred on our debt facilities and amortization of debt discounts and issuance costs.
Other expense, net primarily consists of foreign exchange gains and losses and realized gains and losses from the sale of short-term investments.
Loss on extinguishment of debt comprises a loss arising from the extinguishment of debt as a result of repayment in full of our revolving debt facility.
Our sponsor earn-out shares, private warrants and redeemable convertible preferred stock warrants are subject to remeasurement to fair value at each balance sheet date. Changes in fair value as a result of the remeasurement are recognized in the condensed consolidated statements of operations. We will continue to adjust the outstanding instruments for changes in fair value until the Earn-Out Triggering Events are met, the earlier of the exercise or expiration of the warrants.
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