At we have a consolidated federal net operating loss (“NOL”) carryforward of approximately million available to offset against future taxable income of which approximately million expires in varying amounts in through Additionally, we have approximately million in research and development (“R&D”) tax credits that expire in through unless utilized earlier. income taxes have been paid to date. Section of the Internal Revenue Code contains provisions that limit our utilization of our NOL and R&D tax credit carryforwards in any given year as a result of significant changes in ownership interests that have occurred in past periods or occur in future periods.

 

Deferred income taxes reflect the net effect of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of our deferred tax assets and liabilities included the following at and

 

 

We have established a full valuation allowance equal to the amount of our net deferred tax assets due to uncertainties with respect to our ability to generate sufficient taxable income to realize these assets in the future. A reconciliation of the income tax benefit on losses at the U.S. federal statutory rate to the reported income tax expense is as follows: