This excerpt taken from the SVVS 10-K filed Mar 4, 2005.
Accounting for Income Taxes
We have provided a full valuation allowance on tax loss carry-forwards and other potential tax benefits according to Statement of Financial Accounting Standards No. 109, Accounting for Income Taxes. As a result, to the extent that we realize those benefits in future periods, they will favorably affect net income. We have recorded a valuation allowance for the full amount of our net deferred tax assets because the future realization of the tax benefit is uncertain. At December 31, 2004, we had approximately $550.5 million in United States net operating loss carry-forwards expiring between 2011 and 2023, of which approximately $253.2 million is subject to the Section 382 limitation of the Internal Revenue Code.