Income Taxes	3 Months Ended
Mar. 31, 2014
Income Taxes
Income Taxes	Note 12. Income Taxes Our tax provision for interim periods is determined using an estimate of our annual effective tax rate, adjusted for discrete items, if any, that are taken into account in the relevant period. Each quarter we update our estimate of the annual effective tax rate, and if our estimated tax rate changes, we make a cumulative adjustment. Our quarterly tax provision, and our quarterly estimate of our annual effective tax rate, is subject to significant volatility due to several factors, including variability in accurately predicting our pre-tax and taxable income and loss and the mix of jurisdictions to which they relate, income and losses from investments, changes in tax laws and relative changes of expenses or losses for which tax benefits are not recognized. Additionally, our effective tax rate can be more or less volatile based on the amount of pre-tax income. For example, the impact of discrete items and non-deductible expenses on our effective tax rate is greater when our pre-tax income is lower. Income tax expense was approximately $3.2 million for the three months ended March 31, 2014 compared to an income tax benefit of $5.6 million for the three months ended March 31, 2013. Our effective income tax rate was 20.8% for the three months ended March 31, 2014 compared to 262.8% for the same period in 2013. The variation in our current year effective tax rate from a U.S. federal statutory rate for the current period was primarily due to the increase of our valuation allowance associated with realized and unrealized losses that are capital in nature for tax purposes and a lower state effective tax rate. For the same period in 2013, the variation in our effective tax rate from a U.S. federal statutory rate was primarily due to the decrease of our valuation allowance associated with realized and unrealized losses that are capital in nature for tax purposes, current year research and experimentation credits, and reinstatement of the tax credit for 2012, as provided by the American Taxpayer Relief Act enacted on January 2, 2013.

Income Taxes

3 Months Ended

Mar. 31, 2014

Note 12. Income Taxes

Our tax provision for interim periods is determined using an estimate of our annual effective tax rate, adjusted for discrete items, if any, that are taken into account in the relevant period. Each quarter we update our estimate of the annual effective tax rate, and if our estimated tax rate changes, we make a cumulative adjustment.

Our quarterly tax provision, and our quarterly estimate of our annual effective tax rate, is subject to significant volatility due to several factors, including variability in accurately predicting our pre-tax and taxable income and loss and the mix of jurisdictions to which they relate, income and losses from investments, changes in tax laws and relative changes of expenses or losses for which tax benefits are not recognized. Additionally, our effective tax rate can be more or less volatile based on the amount of pre-tax income. For example, the impact of discrete items and non-deductible expenses on our effective tax rate is greater when our pre-tax income is lower.

Income tax expense was approximately $3.2 million for the three months ended March 31, 2014 compared to an income tax benefit of $5.6 million for the three months ended March 31, 2013. Our effective income tax rate was 20.8% for the three months ended March 31, 2014 compared to 262.8% for the same period in 2013. The variation in our current year effective tax rate from a U.S. federal statutory rate for the current period was primarily due to the increase of our valuation allowance associated with realized and unrealized losses that are capital in nature for tax purposes and a lower state effective tax rate. For the same period in 2013, the variation in our effective tax rate from a U.S. federal statutory rate was primarily due to the decrease of our valuation allowance associated with realized and unrealized losses that are capital in nature for tax purposes, current year research and experimentation credits, and reinstatement of the tax credit for 2012, as provided by the American Taxpayer Relief Act enacted on January 2, 2013.