and networks, impersonation of authorized users, and efforts to discover and exploit any design flaws, bugs, security vulnerabilities or security weaknesses, as well as intentional or unintentional acts by employees or other insiders with access privileges, intentional acts of vandalism by third parties and sabotage. In addition, federal, state and international laws and regulations, such as GDPR, can expose us to enforcement actions and investigations by regulatory authorities, and potentially result in regulatory penalties and significant legal liability, if our information technology security efforts fail. In addition, a variety of our software systems are cloud-based data management applications, hosted by third-party service providers whose security and information technology systems are subject to similar risks.
The failure of either our or our service providers’ information technology could disrupt our entire operation or result in decreased sales, increased overhead costs, product shortages, loss or misuse of proprietary or confidential information, intellectual property or sensitive or personal information, all of which could have a material adverse effect on our reputation, business, financial condition and operating results.
We cannot be certain that our net operating loss tax carryforwards will be available to offset future taxable income.
At December 31, 2018, we had approximately $154.5 million, $120.6 million and $15.8 million of net operating loss carryforwards for federal, state and foreign purposes, respectively, available to offset future taxable income. The federal net operating loss carryforwards incurred prior to 2018 will being to expire in 2019. A federal net operating loss carryforward of $27.2 million will not expire, but can only be used to offset 80 percent of future taxable income. The state net operating loss carryforwards will begin to expire in 2019. The foreign net operating losses will begin to expire in 2023. At December 31, 2018, we had federal and state research and development carryforwards of approximately $9.1 million and $8.1 million, respectively, which begin to expire in 2021 for federal purposes and carry over indefinitely for state purposes. We have recorded a full valuation allowance against these tax attributes because we believe that uncertainty exists with respect to the future realization of the tax attributes as well as with respect to the amount of the tax attributes that will be available in future periods. To the extent available, we intend to use these net operating loss carryforwards to offset future taxable income associated with our operations. There can be no assurance that we will generate sufficient taxable income in the carryforward period to utilize any remaining net operating loss carryforwards before they expire.
In addition, Section 382 of the Internal Revenue Code of 1986, as amended (the Code) contains rules that limit for U.S. federal income tax purposes the ability of a corporation that undergoes an “ownership change” to utilize its net operating losses (and certain other tax attributes) existing as of the date of such ownership change. Under these rules, a corporation is treated as having had an “ownership change” if there is more than a 50% increase in stock ownership by one or more “five percent shareholders,” within the meaning of Section 382 of the Code, during a rolling three-year period. We believe a portion of our existing net operating losses are subject to limitations arising from previous ownership changes, and if we undergo an ownership change, our ability to utilize our net operating losses to offset future taxable income could be further limited, which could have a negative effect on our liquidity. For these reasons, we may not be able to utilize a material portion of our net operating losses, even if we continue to achieve profitability.
Risks Related to the Regulatory Environment
Our failure to obtain and maintain regulatory clearances or approvals on a timely basis, or at all, could prevent us from commercializing our current or pipeline products in the U.S., which could severely impede our ability to grow our business and/or harm our business, financial condition and operating results.
The iStent and the iStent inject are classified as medical devices. As a result, we are subject to extensive government regulation in the United States by the FDA and state regulatory authorities and by foreign regulatory authorities in the countries in which we conduct business. These regulations relate to, among other things, research and development, design, testing, clinical trials, manufacturing, clearance or approval, environmental controls, safety and efficacy, labeling, advertising, promotion, pricing, recordkeeping, reporting, import and export, post-approval studies and the sale and distribution of the iStent, the iStent inject and our other products in development.
In the United States, before we can market a new medical device, or a new use of, new claim for, or significant modification to, an existing product, we must first receive either clearance under Section 510(k) of the Federal Food, Drug and Cosmetic Act (FDCA) or approval of a premarket approval application (PMA) from the FDA, unless an exemption applies. The process of obtaining PMA approval, which was required for the iStent and the iStent inject, is much more costly and uncertain than the 510(k) clearance process. In the 510(k) clearance process, the FDA must determine that a proposed device is “substantially equivalent” to a device legally on the market, known as a “predicate” device, in order to clear the proposed device for marketing. To be “substantially equivalent,” the proposed device must have the same intended use as the predicate device, and either have the same technological characteristics as the