Income Taxes	3 Months Ended
Mar. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Our tax provision for income taxes for interim periods is determined using an estimate of our annual effective tax rate, adjusted for discrete items, if any, that arise during the period. Each quarter, we update our estimate of the annual effective tax rate, and if the estimated annual effective tax rate changes, we make a cumulative adjustment in such period. Our quarterly tax provision, and estimate of our annual effective tax rate, is subject to variation due to several factors, including variability in pre-tax income (or loss), the mix of jurisdictions to which such income relates, changes in how we do business, and tax law developments. Our estimated effective tax rate for the year differs from the U.S. statutory rate of 21% primarily due to non-deductible stock-based compensation expense, state taxes, foreign income subject to different tax rates than the U.S., and the benefit of U.S. federal income tax credits. The Company recorded an income tax provision of $0.5 million and income tax benefit of $13.8 million for the three months ended March 31, 2018 and 2017, respectively. The Company's effective income tax rate was approximately 5.3% and (170.4)% for the three months ended March 31, 2018 and 2017, respectively. On December 22, 2017, the Tax Cuts and Jobs Act (the “2017 Tax Act”) was enacted into law. The new legislation contains significant tax provisions that affect the Company, including a one-time repatriation tax on accumulated foreign earnings, a reduction of the corporate income tax rate from 35% to 21%, which was effective January 1, 2018, and a change from a worldwide tax system to a modified territorial system. In accordance with Staff Accounting Bulletin No. 118 ("SAB 118"), the effects of the 2017 Tax Act may be adjusted within a one-year measurement period from the enactment date of the 2017 Tax Act for items that were previously reported as provisional estimates, or where a provisional estimate could not be made. The income tax provision for the three months ended March 31, 2018, does not reflect any adjustment to the provisional estimates recorded in the year ended December 31, 2017. The Company will continue to assess forthcoming guidance and accounting interpretations on the effects of the 2017 Tax Act and expects to complete its analysis within the measurement period in accordance with the SEC guidance. Such analysis includes both the implications of the newly introduced provisions for Global Intangible Low Tax Income and the detailed analysis of historical foreign earnings and potential correlative adjustments to verify the one-time transition tax does not apply. As of March 31, 2018, the Company had unrecognized tax benefits of $5.3 million, of which $3.0 million, if recognized, would favorably impact the Company's effective tax rate. As of December 31, 2017, the Company had unrecognized tax benefits of $5.1 million, of which $2.8 million, if recognized, would favorably impact the Company's effective tax rate. The Company does not anticipate a material change in its unrecognized tax benefits in the next 12 months.

Income Taxes

Our tax provision for income taxes for interim periods is determined using an estimate of our annual effective tax rate, adjusted for discrete items, if any, that arise during the period. Each quarter, we update our estimate of the annual effective tax rate, and if the estimated annual effective tax rate changes, we make a cumulative adjustment in such period.

Our quarterly tax provision, and estimate of our annual effective tax rate, is subject to variation due to several factors, including variability in pre-tax income (or loss), the mix of jurisdictions to which such income relates, changes in how we do business, and tax law developments. Our estimated effective tax rate for the year differs from the U.S. statutory rate of 21% primarily due to non-deductible stock-based compensation expense, state taxes, foreign income subject to different tax rates than the U.S., and the benefit of U.S. federal income tax credits.

The Company recorded an income tax provision of $0.5 million and income tax benefit of $13.8 million for the three months ended March 31, 2018 and 2017, respectively. The Company's effective income tax rate was approximately 5.3% and (170.4)% for the three months ended March 31, 2018 and 2017, respectively.

On December 22, 2017, the Tax Cuts and Jobs Act (the “2017 Tax Act”) was enacted into law. The new legislation contains significant tax provisions that affect the Company, including a one-time repatriation tax on accumulated foreign earnings, a reduction of the corporate income tax rate from 35% to 21%, which was effective January 1, 2018, and a change from a worldwide tax system to a modified territorial system.

In accordance with Staff Accounting Bulletin No. 118 ("SAB 118"), the effects of the 2017 Tax Act may be adjusted within a one-year measurement period from the enactment date of the 2017 Tax Act for items that were previously reported as provisional estimates, or where a provisional estimate could not be made. The income tax provision for the three months ended March 31, 2018, does not reflect any adjustment to the provisional estimates recorded in the year ended December 31, 2017. The Company will continue to assess forthcoming guidance and accounting interpretations on the effects of the 2017 Tax Act and expects to complete its analysis within the measurement period in accordance with the SEC guidance. Such analysis includes both the implications of the newly introduced provisions for Global Intangible Low Tax Income and the detailed analysis of historical foreign earnings and potential correlative adjustments to verify the one-time transition tax does not apply.

As of March 31, 2018, the Company had unrecognized tax benefits of $5.3 million, of which $3.0 million, if recognized, would favorably impact the Company's effective tax rate. As of December 31, 2017, the Company had unrecognized tax benefits of $5.1 million, of which $2.8 million, if recognized, would favorably impact the Company's effective tax rate. The Company does not anticipate a material change in its unrecognized tax benefits in the next 12 months.