Income taxes	9 Months Ended
Sep. 30, 2018
Income taxes
Income taxes	14. Income taxes For the three and nine months ended September 30, 2018, we recorded income tax expense of approximately $1.8 million and $4.2 million, respectively. For the three and nine months ended September 30, 2017, we recorded income tax expense of approximately $7.3 million and an income tax benefit of approximately $0.5 million, respectively. The change in tax expense for the three and nine months ended September 30, 2018 was primarily driven by the difference in projected annual operating income or loss compared to our actual results as well as the recognition of certain discrete items in the current period. As of September 30, 2018, a full valuation allowance continues to be recorded against our U.S. and Swiss net deferred tax assets. This position is based on an analysis of positive and negative evidence, including analyzing three-year cumulative pre-tax income or loss, projections of future taxable income as well as other quantitative and qualitative information. The balance of our unrecognized tax benefits (including penalties and interest) increased by approximately $5.9 million during the nine months ended September 30, 2018, of which only $0.4 million was recorded as an increase to noncurrent other liabilities on the condensed consolidated balance sheet. The increase is primarily driven by unrecognized tax benefits related to current year operations and prior year positions related to research and development tax credits. On December 22, 2017, the Tax Cuts and Jobs Act of 2017 was signed into law, making significant changes to the Internal Revenue Code. The Act contains numerous provisions impacting corporate taxpayers. Changes include a federal corporate tax rate decrease from 35% to 21% effective for tax years beginning after December 31, 2017, the transition of U.S. international taxation from a worldwide tax system to a territorial system and temporary full expensing of certain business assets. We recorded provisional tax impacts related to the revaluation of deferred tax assets and liabilities as well as the temporary full expensing of certain business assets in our consolidated financial statements for the year ended December 31, 2017. We continue to monitor and analyze further issued guidance, however no additional tax effects of the Act were required to be recorded for the nine months ended September 30, 2018. The financial statement impact is expected to be complete when the 2017 U.S. federal and state corporate income tax returns are filed during the fourth quarter of 2018.

14. Income taxes

For the three and nine months ended September 30, 2018, we recorded income tax expense of approximately $1.8 million and $4.2 million, respectively. For the three and nine months ended September 30, 2017, we recorded income tax expense of approximately $7.3 million and an income tax benefit of approximately $0.5 million, respectively. The change in tax expense for the three and nine months ended September 30, 2018 was primarily driven by the difference in projected annual operating income or loss compared to our actual results as well as the recognition of certain discrete items in the current period.

As of September 30, 2018, a full valuation allowance continues to be recorded against our U.S. and Swiss net deferred tax assets. This position is based on an analysis of positive and negative evidence, including analyzing three-year cumulative pre-tax income or loss, projections of future taxable income as well as other quantitative and qualitative information.

The balance of our unrecognized tax benefits (including penalties and interest) increased by approximately $5.9 million during the nine months ended September 30, 2018, of which only $0.4 million was recorded as an increase to noncurrent other liabilities on the condensed consolidated balance sheet. The increase is primarily driven by unrecognized tax benefits related to current year operations and prior year positions related to research and development tax credits.

On December 22, 2017, the Tax Cuts and Jobs Act of 2017 was signed into law, making significant changes to the Internal Revenue Code. The Act contains numerous provisions impacting corporate taxpayers. Changes include a federal corporate tax rate decrease from 35% to 21% effective for tax years beginning after December 31, 2017, the transition of U.S. international taxation from a worldwide tax system to a territorial system and temporary full expensing of certain business assets. We recorded provisional tax impacts related to the revaluation of deferred tax assets and liabilities as well as the temporary full expensing of certain business assets in our consolidated financial statements for the year ended December 31, 2017. We continue to monitor and analyze further issued guidance, however no additional tax effects of the Act were required to be recorded for the nine months ended September 30, 2018. The financial statement impact is expected to be complete when the 2017 U.S. federal and state corporate income tax returns are filed during the fourth quarter of 2018.