Income Taxes	3 Months Ended
Jan. 02, 2016
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES Income tax expense includes a provision for federal, state and foreign taxes based on the annual estimated effective tax rate applicable to us and our subsidiaries, adjusted for items which are considered discrete to the period. Our effective tax rate for the three months ended January 2, 2016 was 25.0%. Our effective tax rate for the three months ended January 2, 2016 was lower than the statutory rate of 35% primarily due to differences related to the benefit of income subject to foreign tax rates that are lower than U.S. tax rates including the Singapore tax exemption, the benefit of foreign tax credits and the benefit of federal research and development tax credits including renewal of the federal research and development tax credits for fiscal 2015. These amounts are partially offset by deemed dividend inclusions under the Subpart F tax rules, stock-based compensation not deductible for tax purposes and limitations on the deductibility of compensation under IRC Section 162(m). The effective tax rate on income before income taxes for the first quarter of fiscal 2015 of 26.2% was lower than the statutory rate of 35.0% primarily due to differences related to the benefit of income subject to foreign tax rates that are lower than U.S. tax rates including South Korea and Singapore tax exemptions, the benefit of foreign tax credits and the benefit of federal research and development tax credits including renewal of the federal research and development tax credits for fiscal 2014. These amounts are partially offset by deemed dividend inclusions under the Subpart F tax rules, stock-based compensation not deductible for tax purposes and limitations on the deductibility of compensation under IRC Section 162(m). Determining the consolidated provision for income taxes, income tax liabilities and deferred tax assets and liabilities involves judgment. We calculate and provide for income taxes in each of the tax jurisdictions in which we operate, which involves estimating current tax exposures as well as making judgments regarding the recoverability of deferred tax assets in each jurisdiction. The estimates used could differ from actual results, which may have a significant impact on operating results in future periods. We are subject to taxation and file income tax returns in the U.S. federal jurisdiction and in many state and foreign jurisdictions. For U.S. federal income tax purposes, all years prior to 2011 are closed. In our major foreign jurisdictions and our major state jurisdictions, the years prior to 2006 and 2011, respectively, are closed to examination. Earlier years in our various jurisdictions may remain open for adjustment to the extent that we have tax attribute carryforwards from those years. In December 2011 and January 2012, three of our German subsidiaries received notices of tax audits for the fiscal years 2006 through 2010. In fiscal year 2013, we received a preliminary assessment for two of the German subsidiaries and the amount is immaterial. In September 2015, the German tax authorities issued preliminary tax findings for Coherent GmbH for the years 2006 to 2010 and Coherent management met with the German tax authorities in December 2015 to discuss the preliminary assessments. In July 2015, Coherent Kaiserslautern GmbH (formerly Lumera Laser GmbH) received a tax audit notice for the years 2010 to 2013. The audit began in August 2015. We acquired the shares of Lumera Laser GmbH in December 2012 and we should not have responsibility for any assessments related to the pre-acquisition period. Management believes that it has adequately provided reserves for any adjustments that may result from tax examinations. We regularly engage in discussions and negotiations with tax authorities regarding tax matters in various jurisdictions. It is reasonably possible that certain federal, foreign and state tax matters may be concluded in the next 12 months. The Consolidated Appropriations Act of 2016 (“the Act”), was enacted on December 18, 2015. Under the Act, the federal research and development tax credit was retroactively extended for amounts paid or incurred after December 31, 2014 through December 31, 2015 and the credit was made permanent. The effects of the change in the tax law are recognized in our first quarter of fiscal 2016, which is the quarter that the law was enacted. Accordingly, prior year research and development tax credits of approximately $1.2 million, after netting with appropriate reserves, were recognized in the first quarter of fiscal 2016.

INCOME TAXES

Income tax expense includes a provision for federal, state and foreign taxes based on the annual estimated effective tax rate applicable to us and our subsidiaries, adjusted for items which are considered discrete to the period. Our effective tax rate for the three months ended January 2, 2016 was 25.0%. Our effective tax rate for the three months ended January 2, 2016 was lower than the statutory rate of 35% primarily due to differences related to the benefit of income subject to foreign tax rates that are lower than U.S. tax rates including the Singapore tax exemption, the benefit of foreign tax credits and the benefit of federal research and development tax credits including renewal of the federal research and development tax credits for fiscal 2015. These amounts are partially offset by deemed dividend inclusions under the Subpart F tax rules, stock-based compensation not deductible for tax purposes and limitations on the deductibility of compensation under IRC Section 162(m).

The effective tax rate on income before income taxes for the first quarter of fiscal 2015 of 26.2% was lower than the statutory rate of 35.0% primarily due to differences related to the benefit of income subject to foreign tax rates that are lower than U.S. tax rates including South Korea and Singapore tax exemptions, the benefit of foreign tax credits and the benefit of federal research and development tax credits including renewal of the federal research and development tax credits for fiscal 2014. These amounts are partially offset by deemed dividend inclusions under the Subpart F tax rules, stock-based compensation not deductible for tax purposes and limitations on the deductibility of compensation under IRC Section 162(m).

Determining the consolidated provision for income taxes, income tax liabilities and deferred tax assets and liabilities involves judgment. We calculate and provide for income taxes in each of the tax jurisdictions in which we operate, which involves estimating current tax exposures as well as making judgments regarding the recoverability of deferred tax assets in each jurisdiction. The estimates used could differ from actual results, which may have a significant impact on operating results in future periods.

We are subject to taxation and file income tax returns in the U.S. federal jurisdiction and in many state and foreign jurisdictions. For U.S. federal income tax purposes, all years prior to 2011 are closed. In our major foreign jurisdictions and our major state jurisdictions, the years prior to 2006 and 2011, respectively, are closed to examination. Earlier years in our various jurisdictions may remain open for adjustment to the extent that we have tax attribute carryforwards from those years. In December 2011 and January 2012, three of our German subsidiaries received notices of tax audits for the fiscal years 2006 through 2010. In fiscal year 2013, we received a preliminary assessment for two of the German subsidiaries and the amount is immaterial. In September 2015, the German tax authorities issued preliminary tax findings for Coherent GmbH for the years 2006 to 2010 and Coherent management met with the German tax authorities in December 2015 to discuss the preliminary assessments. In July 2015, Coherent Kaiserslautern GmbH (formerly Lumera Laser GmbH) received a tax audit notice for the years 2010 to 2013. The audit began in August 2015. We acquired the shares of Lumera Laser GmbH in December 2012 and we should not have responsibility for any assessments related to the pre-acquisition period.

Management believes that it has adequately provided reserves for any adjustments that may result from tax examinations. We regularly engage in discussions and negotiations with tax authorities regarding tax matters in various jurisdictions. It is reasonably possible that certain federal, foreign and state tax matters may be concluded in the next 12 months.

The Consolidated Appropriations Act of 2016 (“the Act”), was enacted on December 18, 2015. Under the Act, the federal research and development tax credit was retroactively extended for amounts paid or incurred after December 31, 2014 through December 31, 2015 and the credit was made permanent. The effects of the change in the tax law are recognized in our first quarter of fiscal 2016, which is the quarter that the law was enacted. Accordingly, prior year research and development tax credits of approximately $1.2 million, after netting with appropriate reserves, were recognized in the first quarter of fiscal 2016.