The Company and Its Significant Accounting Policies	3 Months Ended
The Company and Its Significant Accounting Policies	Sep. 30, 2011
Accounting Policies [Abstract]
The Company and Its Significant Accounting Policies	The Company and Significant Accounting Policies The Company Alpha and Omega Semiconductor Limited and its subsidiaries (the “Company”, "AOS", "we" or "us") design, develop and supply a broad range of power semiconductors. The Company's portfolio of products targets high-volume applications, including portable computers, flat panel TVs, smart phones, battery packs, portable media players, motor control and power supplies. The Company conducts its operations primarily in the United States of America (“USA”), Hong Kong, Macau, China, Taiwan, Korea and Japan. Basis of Preparation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”) for interim financial information and with the instructions to Article 10 of Securities and Exchange Commission Regulation S-X. They do not include all information and footnotes necessary for a fair presentation of financial position, results of operations and cash flows in conformity with U.S. GAAP for complete financial statements. These condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and related notes contained in the Company’s Annual Report on Form 10-K for the year ended June 30, 2011. All significant intercompany balances and transactions have been eliminated in consolidation. In the opinion of management, all adjustments (consisting of normal recurring adjustments and accruals) considered necessary for a fair presentation of the results of operations for the period presented have been included in the interim period. Operating results for the three months ended September 30, 2011 are not necessarily indicative of the results that may be expected for other interim periods or the year ending June 30, 2012. The condensed consolidated financial data at June 30, 2011 is derived from the audited financial statements included in the Company’s Annual Report on Form 10-K for the year ended June 30, 2011. Use of Estimates The preparation of our consolidated financial statements in conformity with U.S. GAAP requires the Company to make estimates, judgments and assumptions that affect the reported amounts of assets, liabilities, revenue and expenses. To the extent there are material differences between these estimates and actual results, the Company's consolidated financial statements will be affected. On an ongoing basis, the Company evaluates the estimates, judgments and assumptions including those related to revenue recognition, inventory reserves, warranty reserve, income taxes, share-based compensation, variable interest entities and useful lives for property and equipment and for intangible assets. Recently Issued Accounting Guidance In September 2011, the FASB issued an amendment to Topic 350, Intangibles-Goodwill and Other, which simplifies how entities test goodwill for impairment. Previous guidance under Topic 350 required an entity to test goodwill for impairment using a two-step process on at least an annual basis. First, the fair value of a reporting unit was calculated and compared to its carrying amount, including goodwill. Second, if the fair value of a reporting unit was less than its carrying amount, the amount of impairment loss, if any, was required to be measured. Under the amendments in this update, an entity has the option to first assess qualitative factors to determine whether the existence of events or circumstances leads the entity to determine that it is more likely than not that its fair value is less than its carrying amount. If after assessing the totality of events or circumstances, an entity determines that it is not more likely than not that the fair value of the reporting unit is less than its carrying amount, then the two-step impairment test is unnecessary. If the entity concludes otherwise, then it is required to test goodwill for impairment under the two-step process as described under Topic 350. The amendments are effective for annual and interim goodwill impairment tests performed for fiscal years beginning after December 15, 2011 and early adoption is permitted. The Company currently does not have goodwill and does not expect the adoption of the updated guidance have an impact on its consolidated financial statements

The entire disclosure for the organization, consolidation and basis of presentation of financial statements disclosure, and significant accounting policies of the reporting entity. May be provided in more than one note to the financial statements, as long as users are provided with an understanding of (1) the significant judgments and assumptions made by an enterprise in determining whether it must consolidate a VIE and/or disclose information about its involvement with a VIE, (2) the nature of restrictions on a consolidated VIE's assets reported by an enterprise in its statement of financial position, including the carrying amounts of such assets, (3) the nature of, and changes in, the risks associated with an enterprise's involvement with the VIE, and (4) how an enterprise's involvement with the VIE affects the enterprise's financial position, financial performance, and cash flows. Describes procedure if disclosures are provided in more than one note to the financial statements.