Description of Business and Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2015

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Goodwill and Intangible Assets, Policy [Policy Text Block]

Goodwill is recorded when the cost of an acquisition exceeds the fair value of the net tangible and identifiable intangible assets acquired. We review goodwill for impairment annually during the fourth quarter of each year and whenever events or changes in circumstances indicate that an impairment exists. Impairment losses are recorded when the carrying amount of goodwill exceeds its implied fair value. No goodwill impairment has been identified in any of the years presented.

Nature of Operations [Text Block]

Amkor is one of the world’s leading providers of outsourced semiconductor packaging and test services. Amkor pioneered the outsourcing of semiconductor packaging and test services through a predecessor corporation in 1968, and over the years we have built a leading position by:

• Designing and developing innovative packaging and test technologies;

• Offering a broad portfolio of cost-effective solutions and services;

• Successfully penetrating strategic end markets which offer solid growth prospects;

• Cultivating long-standing relationships with our customers, which include many of the world’s leading semiconductor companies;

• Collaborating with customers, original equipment manufacturers ("OEMs") and equipment and material suppliers;

• Developing a competitive cost structure with disciplined capital investment;

• Building expertise in high-volume manufacturing processes and developing a reputation for high quality and solid execution and

• Providing a geographically diverse operating base with research and development, engineering and production capabilities at various facilities throughout China, Japan, Korea, Malaysia, the Philippines and Taiwan.

Basis of Presentation

Our Consolidated Financial Statements include the accounts of Amkor Technology, Inc. and our subsidiaries (“Amkor”). Our Consolidated Financial Statements reflect the elimination of all significant inter-company accounts and transactions. On July 31, 2013, we completed the purchase of Amkor Technology Malaysia Sdn. Bhd. The financial results of the entity have been included in our Consolidated Financial Statements from the date of acquisition (Note 3). On June 30, 2014, we completed the sale of our Japanese subsidiary to J-Devices. The financial results of the divested entity were included in our Consolidated Financial Statements up to the date of sale and have subsequently been included in the results of J-Devices. On December 30, 2015, we increased our investment in J-Devices to 100% through the exercise of options. As a result, our accounting for J-Devices changed from the equity method to the consolidation method effective December 30, 2015. Our investments in variable interest entities in which we are the primary beneficiary are consolidated. We reflect the remaining portion of variable interest entities and foreign subsidiaries that are not wholly owned as noncontrolling interests.

Use of Estimates

The preparation of financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. On an ongoing basis, we evaluate our estimates, including those related to acquisitions, revenue recognition, income taxes, inventory, long lived assets and contingencies. These estimates are based on management’s best knowledge of current events, historical experience, actions that we may undertake in the future and on various other assumptions that are believed to be reasonable under the circumstances. As a result, actual results could differ materially from these estimates and assumptions.

Consolidation of Variable Interest Entities

We have variable interests in certain Philippine realty corporations in which we have a 40% ownership and from whom we lease land and buildings in the Philippines, for which we are the primary beneficiary. As of December 31, 2015, the combined book value of the assets and liabilities associated with these Philippine realty corporations included in our Consolidated Balance Sheet was $16.9 million and $0.2 million, respectively. The impact of consolidating these variable interest entities on our Consolidated Statements of Income was not significant, and other than our lease payments, we have not provided any significant assistance or other financial support to these variable interest entities for the years ended December 31, 2015, 2014 or 2013. The creditors of the Philippine realty corporations have no recourse to our general credit.

Foreign Currency Translation

The U.S. dollar is the functional currency of our subsidiaries, with the exception of J-Devices, and the foreign currency asset and liability amounts at these subsidiaries are remeasured into U.S. dollars at end-of-period exchange rates, except for nonmonetary items which are remeasured at historical rates. Foreign currency income and expenses are remeasured at daily exchange rates, except for expenses related to balance sheet amounts which are remeasured at historical exchange rates. Exchange gains and losses arising from remeasurement of foreign currency-denominated monetary assets and liabilities are included in other (income) expense, net in the period in which they occur.

The Japanese Yen is the functional currency of J-Devices. The asset and liability amounts of J-Devices are translated into U.S. dollars at end-of-period exchange rates. Income and expenses are translated into U.S. dollars at average exchange rates in effect during the period. The resulting translation adjustments are reported as a component of accumulated other comprehensive income in the stockholders’ equity section of the balance sheet. Assets and liabilities denominated in a currency other than the functional currency are remeasured into the functional currency prior to translation into U.S. dollars, and the resulting transaction exchange gains or losses are included in other expense (income) in the period in which they occur.

Concentration Risk Disclosure [Text Block]

The semiconductor industry is characterized by rapid technological change, competitive pricing pressures and cyclical market patterns. Our financial results are affected by a wide variety of factors, including general economic conditions worldwide, economic conditions specific to the semiconductor industry, the timely implementation of new package and test technologies, the ability to safeguard patents and intellectual property in a rapidly evolving market and reliance on materials and equipment suppliers. In addition, the semiconductor market has historically been cyclical and subject to significant economic downturns at various times. Our profitability and ability to generate cash from operations is principally dependent upon demand for semiconductors, the utilization of our capacity, semiconductor package mix, the average selling price of our services, our ability to manage our capital expenditures and our ability to control our costs including labor, material, overhead and financing costs.

A significant portion of our revenues is concentrated with a small group of customers (Note 18). The loss of a significant customer, a business combination among customers, a reduction in orders or decrease in price from a significant customer or disruption in any of our significant strategic partnerships or other commercial arrangements could have a material adverse effect on our business, liquidity, results of operations, financial condition and cash flows.

Financial instruments, for which we are subject to credit risk, consist principally of accounts receivable and cash and cash equivalents. With respect to accounts receivable, we mitigate our credit risk by selling primarily to well-established companies, performing ongoing credit evaluations and making frequent contact with customers. In addition, we may utilize non-recourse factoring to mitigate credit risk when considered appropriate. We have historically mitigated our credit risk with respect to cash and cash equivalents through diversification of our holdings into various high quality money market funds and bank deposit accounts. At December 31, 2015, our cash and cash equivalents were invested in U.S. money market funds and various U.S. and foreign bank operating and time deposit accounts.

Risks and Uncertainties

We may be subject to certain legal proceedings, lawsuits and other claims, as discussed in Note 17. We accrue for a loss contingency, including legal proceedings, lawsuits, pending claims and other legal matters, when we conclude that the likelihood of a loss is probable and the amount of the loss can be reasonably estimated. When the reasonable estimate of the loss is within a range of amounts, and no amount in the range constitutes a better estimate than any other amount, we accrue for the amount at the low end of the range. We adjust our accruals from time to time as we receive additional information, but the loss we incur may be significantly greater than or less than the amount we have accrued. We disclose loss contingencies if we believe they are material and there is at least a reasonable possibility that a loss has been incurred. Attorney fees related to legal matters are expensed as incurred.

Cash and Cash Equivalents

We consider all highly liquid investments with a maturity of three months or less when purchased to be cash equivalents. Our cash and cash equivalents consist of amounts invested in U.S. money market funds and various U.S. and foreign bank operating and time deposit accounts.

Restricted Cash

Restricted cash, current, consists of short-term cash equivalents used to collateralize our daily banking services. Restricted cash, non-current, mainly consists of collateral to fulfill foreign trade compliance requirements.

Inventories

Inventories are stated at the lower of cost or market (net realizable value). Cost is principally determined by standard cost (on a first-in, first-out basis, with the exception of work-in-process which is determined on an average cost basis), all of which approximate actual cost. We review and set our standard costs as needed, but at a minimum on an annual basis. We reduce the carrying value of our inventories for the cost of inventory we estimate is excess and obsolete based on the age of our inventories. When a determination is made that the inventory will not be utilized in production or is not saleable, it is written-off.

Other Current Assets [Text Block]

Other current assets consist principally of prepaid assets, deferred tax assets and an investment in government securities by a foreign subsidiary to satisfy local regulatory requirements, which is recorded at amortized cost.

Property, Plant and Equipment

Property, plant and equipment are stated at cost. Depreciation is calculated by the straight-line method over the estimated useful lives of depreciable assets which are as follows:

Land use rights	50 to 90 years
Buildings and improvements	10 to 40 years
Machinery and equipment	2 to 7 years
Software and computer equipment	3 to 5 years
Furniture, fixtures and other equipment	4 to 10 years

Cost and accumulated depreciation for property retired or disposed of are removed from the accounts, and any resulting gain or loss is included in earnings. Expenditures for maintenance and repairs are charged to expense as incurred.

We review long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. Recoverability of a long-lived asset group to be held and used in operations is measured by a comparison of the carrying amount to the sum of the undiscounted cash flows expected to result from the use and eventual disposition of the asset group. If such asset group is considered to be impaired, the impairment loss is measured as the amount by which the carrying amount of the asset group exceeds its fair value. Long-lived assets to be disposed of are carried at the lower of cost or fair value less the costs of disposal.

Investments

Our investment in J-Devices, a previously unconsolidated joint venture to provide semiconductor packaging and test services in Japan, was accounted for as an equity method investment before our ownership reached 100% on December 30, 2015. We evaluated our investment for other-than-temporary impairment whenever events or changes in circumstances indicated that the fair value of the investment may have been less than its carrying value. See Note 3 for additional information.

Schedule of Other Assets, Noncurrent [Table Text Block]

Other assets consist principally of deferred tax assets, refundable security deposits and deferred debt issuance costs.

Other Noncurrent Liabilities [Table Text Block]

Other non-current liabilities consist primarily of liabilities associated with the settlement of patent license litigation and uncertain income tax positions. See Note 17 for additional information on the settlement.

Fair Value Measurements

We apply fair value accounting for assets and liabilities that are recognized or disclosed at fair value in the financial statements on a recurring or nonrecurring basis. We define fair value as the price that would be received from selling an asset or paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants at the measurement date. See Note 16 for further discussion of fair value measurements.

Revenue Recognition

We recognize revenue from our packaging and test services, net of value-added or other similar taxes, when there is evidence of an arrangement, delivery has occurred or services have been rendered, fees are fixed or determinable and collectibility is reasonably assured. Generally these criteria are met and revenue is recognized upon shipment or, in some cases, customer acceptance. If the revenue recognition criteria are not met, we defer the revenue. Deferred revenue generally results from two types of transactions: contractual invoicing at interim points in the packaging and test process prior to shipment of the finished product and customer advances for supply agreements with customers where we commit capacity in exchange for customer prepayment of services. These prepayments are deferred and recorded as customer advances within accrued expenses and other non-current liabilities.

We generally do not take ownership of customer-supplied semiconductor wafers. Title and risk of loss remains with the customer for these materials at all times. Accordingly, the cost of the customer-supplied materials is not included in our Consolidated Financial Statements.

An allowance for sales credits is recorded as a reduction to sales and accounts receivable during the period of sale such that accounts receivable is reported at its estimated net realizable value. The allowance for sales credits is an estimate of the future credits we will issue for billing adjustments primarily for invoicing corrections and miscellaneous customer claims and is estimated based upon recent credit issuance, historical experience and specific identification of known or expected sales credits at the end of the reporting period. Additionally, provisions are made for doubtful accounts when there is doubt as to the collectibility of accounts receivable. The allowance for doubtful accounts is recorded as bad debt expense and is classified as selling, general and administrative expense. The allowance for doubtful accounts is based upon specific identification of doubtful accounts considering the age of the receivable balance, the customer’s historical payment history and current credit worthiness as well as specific identification of any known or expected collectibility issues. Historically, our allowance for doubtful accounts has been immaterial.

Shipping and Handling Fees and Costs

Amounts billed to customers for shipping and handling are presented in net sales. Costs incurred for shipping and handling are included in cost of sales.

Research and Development Costs

Research and development expenses include costs attributable to the conduct of research and development programs primarily related to the development of new package designs or technologies and improving the efficiency and capabilities of our existing production processes. Such costs include salaries, payroll taxes, employee benefit costs, materials, supplies, depreciation and maintenance of research equipment, services provided by outside contractors and the allocable portions of facility costs such as rent, utilities, insurance, repairs and maintenance, depreciation and general support services. All costs associated with research and development are expensed as incurred.

Income Taxes

Income taxes are accounted for using the asset and liability method. Under this method, deferred income tax assets and liabilities are recognized for the future tax consequences attributable to temporary differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis as well as for net operating loss and tax credit carryforwards. Deferred income tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which these temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. A valuation allowance is provided for those deferred tax assets for which it is more likely than not that the related tax benefits will not be realized.

We monitor on an ongoing basis our ability to utilize our deferred tax assets and whether there is a need for a related valuation allowance. In evaluating our ability to recover our deferred tax assets in the jurisdictions from which they arise, we consider all available positive and negative evidence, including scheduled reversals of deferred tax liabilities, projected future taxable income, tax-planning strategies and results of recent operations. For most of our foreign deferred tax assets, we consider it more likely than not that we will have sufficient taxable income to allow us to realize these deferred tax assets. However, in the event taxable income falls short of current expectations, we may need to establish a valuation allowance against such deferred tax assets.

We recognize in our Consolidated Financial Statements the impact of an income tax position, if that position is more likely than not of being sustained on audit, based on the technical merits of the position. Related interest and penalties are classified as income taxes in the financial statements. See Note 6 for more information regarding unrecognized income tax benefits.