Cost of subscription services revenue primarily consists of personnel costs associated with delivering our subscription and professional services, part replacements, allocated overhead costs and depreciation of infrastructure used to deliver our subscription services. We expect our cost of subscription services revenue to increase in absolute dollars, as our subscription services revenue increases. Operating Expenses Our operating expenses consist of research and development, sales and marketing and general and administrative expenses. Salaries and personnel-related costs, including stock-based compensation expense, are the most significant component of each category of operating expenses. Operating expenses also include allocated overhead costs for employee benefits and facilities-related costs. Research and Development. Research and development expenses consist primarily of employee compensation and related expenses, prototype expenses, depreciation associated with assets acquired for research and development, third-party engineering and contractor support costs, as well as allocated overhead. We expect our research and development expense to increase in absolute dollars and it may decrease as a percentage of revenue. Sales and Marketing. Sales and marketing expenses consist primarily of employee compensation and related expenses, sales commissions, marketing programs, travel and entertainment expenses as well as allocated overhead. Marketing programs consist of advertising, events, corporate communications and brand-building activities. We expect our sales and marketing expense to increase in absolute dollars and it may decrease as a percentage of revenue as we continue to realize efficiencies from scaling our business. General and Administrative. General and administrative expenses consist primarily of employee compensation and related expenses for administrative functions including finance, legal, human resources, IT and fees for third-party professional services as well as amortization of intangible assets pertaining to defensive technology patents and allocated overhead. We expect our general and administrative expense to increase in absolute dollars and it may decrease as a percentage of revenue. Other Income (Expense), Net Other income (expense), net consists primarily of interest income related to cash, cash equivalents and marketable securities, interest expense related to our debt and gains (losses) from foreign currency transactions. Provision for Income Taxes Provision for income taxes consists primarily of income taxes in certain foreign jurisdictions in which we conduct business and state income taxes in the United States. We have recorded no U.S. federal current income tax and provided a full valuation allowance for U.S. deferred tax assets, which includes net operating loss carryforwards and tax credits related primarily to research and development. We expect to maintain this full valuation allowance for the foreseeable future as it is more likely than not that the assets will not be realized based on our history of losses. 39