Quarterly report pursuant to Section 13 or 15(d)

Income Taxes

Income Taxes
6 Months Ended
Jun. 30, 2011
Income Taxes [Abstract]  
Income Taxes
10. Income Taxes
We make estimates and judgments in determining income tax expense for financial statement purposes. These estimates and judgments occur in the calculation of certain tax assets and liabilities, which arise from differences in the timing of recognition of revenue and expense for tax and financial statement purposes.
Our tax provision for interim periods is derived using an estimate of our annual effective rate, adjusted for any material items.