Income Taxes	6 Months Ended
Mar. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes For the three months ended March 31, 2019 and 2018, we recorded income tax expense of $0.3 million and $0.4 million, respectively. For the six months ended March 31, 2019 and 2018, we recorded income tax expense of $0.9 million and $1.6 million, respectively. The quarterly income tax provision is calculated using an estimated annual effective tax rate, based upon expected annual income, permanent items, statutory rates and planned tax strategies in the various jurisdictions in which we operate. However, losses in certain jurisdictions and discrete items are treated separately. For the three and six months ended March 31, 2018, we recorded an income tax benefit of $3.2 million and $3.1 million, respectively, related to our discontinued operations. This benefit was the result of the resolution of an uncertain tax position in specific tax jurisdictions. We worked with tax experts in the local jurisdictions and in the U.S. to review the transactions and tax laws that resulted in this uncertain tax position, as well as the related interest and penalties. At the conclusion of this review, we determined that the Company is not liable for withholding taxes nor the associated interest and penalties in one of the jurisdictions. Therefore, we reversed the accrued tax, interest and penalties relating to this jurisdiction. Deferred tax assets and liabilities reflect the tax effects of temporary differences between the carrying value of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. We record a valuation allowance if, based on the weight of available evidence, it is more likely than not that some portion or all of a deferred tax asset will not be realized. Our expectations regarding realization of our deferred tax assets is based upon the weight of all available evidence, including such factors as our recent earnings history, expected future taxable income and available tax planning strategies. We established valuation allowances on substantially all net deferred tax assets, after considering all of the available objective evidence, both positive and negative, historical and prospective, with greater weight given to historical evidence, and determined it is not more likely than not that these assets will be realized. We will continue to monitor our cumulative income and loss positions in the U.S. and foreign jurisdictions to determine whether full valuation allowances on net deferred tax assets are appropriate. We classify all of our uncertain tax positions as income taxes payable long-term. At both March 31, 2019 and September 30, 2018, the total amount of unrecognized tax benefits was approximately $1.2 million. Income taxes payable long-term includes other items, primarily withholding taxes that are not due until the related intercompany service fees are paid. We classify interest and penalties related to unrecognized tax benefits as income tax expense. As of both March 31, 2019 and September 30, 2018, we had an accrual for potential interest and penalties of approximately $0.7 million classified with income taxes payable long-term. Amtech and one or more of our subsidiaries file income tax returns in The Netherlands, Germany, France, China and other foreign jurisdictions, as well as in the U.S. and various states in the U.S. We have not signed any agreements with the Internal Revenue Service, any state or foreign jurisdiction to the extend the statute of limitations for any fiscal year. As such, the number of open years is the number of years dictated by statute in each of the respective taxing jurisdictions, which generally is from 3 to 5 years.

Income Taxes

For the three months ended March 31, 2019 and 2018, we recorded income tax expense of $0.3 million and $0.4 million, respectively. For the six months ended March 31, 2019 and 2018, we recorded income tax expense of $0.9 million and $1.6 million, respectively. The quarterly income tax provision is calculated using an estimated annual effective tax rate, based upon expected annual income, permanent items, statutory rates and planned tax strategies in the various jurisdictions in which we operate. However, losses in certain jurisdictions and discrete items are treated separately.

For the three and six months ended March 31, 2018, we recorded an income tax benefit of $3.2 million and $3.1 million, respectively, related to our discontinued operations. This benefit was the result of the resolution of an uncertain tax position in specific tax jurisdictions. We worked with tax experts in the local jurisdictions and in the U.S. to review the transactions and tax laws that resulted in this uncertain tax position, as well as the related interest and penalties. At the conclusion of this review, we determined that the Company is not liable for withholding taxes nor the associated interest and penalties in one of the jurisdictions. Therefore, we reversed the accrued tax, interest and penalties relating to this jurisdiction.

Deferred tax assets and liabilities reflect the tax effects of temporary differences between the carrying value of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. We record a valuation allowance if, based on the weight of available evidence, it is more likely than not that some portion or all of a deferred tax asset will not be realized. Our expectations regarding realization of our deferred tax assets is based upon the weight of all available evidence, including such factors as our recent earnings history, expected future taxable income and available tax planning strategies. We established valuation allowances on substantially all net deferred tax assets, after considering all of the available objective evidence, both positive and negative, historical and prospective, with greater weight given to historical evidence, and determined it is not more likely than not that these assets will be realized. We will continue to monitor our cumulative income and loss positions in the U.S. and foreign jurisdictions to determine whether full valuation allowances on net deferred tax assets are appropriate.

We classify all of our uncertain tax positions as income taxes payable long-term. At both March 31, 2019 and September 30, 2018, the total amount of unrecognized tax benefits was approximately $1.2 million. Income taxes payable long-term includes other items, primarily withholding taxes that are not due until the related intercompany service fees are paid.

We classify interest and penalties related to unrecognized tax benefits as income tax expense. As of both March 31, 2019 and September 30, 2018, we had an accrual for potential interest and penalties of approximately $0.7 million classified with income taxes payable long-term.

Amtech and one or more of our subsidiaries file income tax returns in The Netherlands, Germany, France, China and other foreign jurisdictions, as well as in the U.S. and various states in the U.S. We have not signed any agreements with the Internal Revenue Service, any state or foreign jurisdiction to the extend the statute of limitations for any fiscal year. As such, the number of open years is the number of years dictated by statute in each of the respective taxing jurisdictions, which generally is from 3 to 5 years.