generated any significant revenues and have therefore incurred significant net losses since our inception in December 2008. The assets we purchased from BioSciences in April 2009 generated minimal revenues prior to their acquisition. Unless we secure a collaborator for one or more of our product candidates and generate substantial license revenues, we will need additional capital in order to continue to implement our business strategy. Although we have raised capital in the past and raised net proceeds of approximately $15.2 million and $19.4 million through the sale of common stock in 2012 and 2011, respectively, we cannot assure you that we will be able to secure such additional financing, if needed, or that it will be adequate to execute our business strategy. Even if we obtain additional financing, it may be costly and may require us to agree to covenants or other provisions that will favor new investors over existing shareholders. Due to the time required to conduct clinical trials and obtain regulatory approval for any of our product candidates, we anticipate it will be some time before we generate substantial revenues, if ever. We expect to generate operating losses for the foreseeable future, but intend to try to limit the extent of these losses by entering into co-development or collaboration agreements with one or more strategic partners, such as the license agreement entered into in September 2011 with a major Korean pharmaceutical company.
At this time, due to the risks inherent in the clinical trials and the stage of development of our product candidates, we are unable to estimate with any certainty the costs we will incur for the continued development of our product candidates for commercialization as clinical development timelines, probability of success, and development costs vary widely. While our current focus is primarily on obtaining regulatory approval for our product candidates, initiating pre-clinical development of our methylphenidate product family, and the development of the ORP device, we anticipate that we will make determinations on an ongoing basis as to which product candidates to pursue and how much funding to direct to each product candidate in response to the scientific and clinical success of each product candidate, as well as an ongoing assessment of each product candidate's commercial potential and our financial position. We cannot forecast with any degree of certainty which product candidates will be subject to future collaborative or licensing arrangements, when such arrangements will be secured, if at all, and to what degree such arrangements would affect our product candidate plans and capital requirements.