Document and Entity Information - shares	3 Months Ended
Document and Entity Information - shares	Sep. 30, 2016	Oct. 31, 2016
Document and Entity Information [Abstract]
Entity Registrant Name	ALPHA & OMEGA SEMICONDUCTOR Ltd
Entity Central Index Key	0001387467
Current Fiscal Year End Date	--06-30
Entity Filer Category	Accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2016
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		23,295,656

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2016	Jun. 30, 2016
Current assets:
Cash and cash equivalents	$ 118,774	$ 87,774
Restricted cash	225	188
Accounts receivable, net	27,059	26,594
Inventories	70,018	68,848
Other current assets	5,314	4,526
Total current assets	221,390	187,930
Property, plant and equipment, net	123,048	116,084
Deferred income tax assets - long term	5,486	12,132
Other long-term assets	10,642	2,359
Total assets	360,566	318,505
Current liabilities:
Accounts payable	38,644	42,718
Accrued liabilities	25,977	22,590
Income taxes payable	2,667	2,356
Deferred margin	1,003	997
Capital leases	801	819
Total current liabilities	69,092	69,480
Income taxes payable - long term	1,592	1,577
Deferred income tax liabilities	2,972	2,973
Capital leases - long term	1,496	1,695
Other long term liabilities	680	741
Total liabilities	75,832	76,466
Commitments and contingencies (Note 9)
Preferred shares, par value $0.002 per share:
Authorized: 10,000 shares, issued and outstanding: none at September 30, 2016 and June 30, 2016	0	0
Common shares, par value $0.002 per share:
Authorized: 50,000 shares, issued and outstanding: 28,928 shares and 23,281 shares, respectively at September 30, 2016 and 28,405 shares and 22,754 shares, respectively at June 30, 2016	58	57
Treasury shares at cost, 5,647 shares at September 30, 2016 and 5,651 shares at June 30, 2016	(50,166)	(50,199)
Additional paid-in capital	198,615	191,444
Accumulated other comprehensive income	860	769
Retained earnings	103,368	100,071
Total Alpha and Omega Semiconductor Limited shareholder's equity	252,735	242,142
Noncontrolling interest	31,999	(103)
Total equity	284,734	242,039
Total liabilities and equity	$ 360,566	$ 318,505

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2016	Jun. 30, 2016
Common shares, par value (in dollars per share)	$ 0.002	$ 0.002
Common shares, authorized (in shares)	50,000,000	50,000,000
Common stock, shares issued (in shares)	28,928,000	28,405,000
Common stock, shares outstanding (in shares)	23,281,000	22,754,000
Preferred stock, par value (in dollars per share)	$ 0.002	$ 0.002
Preferred stock, shares authorized (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Treasury shares (in shares)	5,647,000	5,651,000

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Revenue	$ 97,362	$ 81,439
Cost of goods sold	75,418	66,378
Gross profit	21,944	15,061
Operating expenses
Research and development	7,019	6,164
Selling, general and administrative	11,183	9,497
Total operating expenses	18,202	15,661
Operating income (loss)	3,742	(600)
Interest income and other income (loss), net	(49)	(151)
Interest expense	(26)	(10)
Net Income (loss) before income taxes	3,667	(761)
Income tax expense	1,237	1,214
Net income (loss) including noncontrolling interest	2,430	(1,975)
Net loss attributable to noncontrolling interest	(877)	0
Net income (loss) attributable to Alpha and Omega Semiconductor Limited	$ 3,307	$ (1,975)
Net income (loss) per common share attributable to Alpha and Omega Semiconductor Limited
Basic (in dollars per share)	$ 0.14	$ (0.09)
Diluted (in dollars per share)	$ 0.14	$ (0.09)
Weighted average number of common shares attributable to Alpha and Omega Semiconductor Limited used to compute net income (loss) per share
Basic (in shares)	23,031	22,698
Diluted (in shares)	24,413	22,698

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Net income (loss) including noncontrolling interest	$ 2,430	$ (1,975)
Foreign currency translation adjustment	70	(166)
Comprehensive income (loss)	2,500	(2,141)
Noncontrolling interest	(898)	0
Comprehensive income (loss) attributable to Alpha and Omega Semiconductor Limited	$ 3,398	$ (2,141)

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities
Net income (loss) including noncontrolling interest	$ 2,430	$ (1,975)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	6,503	6,895
Share-based compensation expense	1,316	789
Deferred income taxes, net	6,645	571
Gain on disposal of property and equipment	(377)	0
Changes in assets and liabilities:
Accounts receivable	(465)	1,583
Inventories	(1,170)	2,217
Other current and long-term assets	(5,690)	595
Accounts payable	(2,804)	(5,193)
Income taxes payable	327	389
Accrued and other liabilities	2,582	1,936
Net cash provided by operating activities	9,297	7,807
Cash flows from investing activities
Purchases of property and equipment	(17,374)	(6,002)
Proceeds from sale of property and equipment	417	0
(Increase) decrease in restricted cash	(37)	172
Net cash used in investing activities	(16,994)	(5,830)
Cash flows from financing activities
Proceeds from investment by noncontrolling interest	33,000	0
Withholding tax on restricted stock units	(132)	(51)
Proceeds from exercise of stock options	6,011	424
Payment for repurchases of common shares	0	(35,240)
Principal payments on capital leases	(215)	(227)
Net cash provided by (used in) financing activities	38,664	(35,094)
Effect of exchange rate changes on cash and cash equivalents	33	(100)
Net increase (decrease) in cash and cash equivalents	31,000	(33,217)
Cash and cash equivalents at beginning of period	87,774	106,085
Cash and cash equivalents at end of period	118,774	72,868
Supplemental disclosures of non-cash investing and financing information:
Property and equipment purchased but not yet paid	5,226	4,472
Re-issuance of treasury stock	$ 10	$ 0

The Company and Significant Accounting Policies	3 Months Ended
The Company and Significant Accounting Policies	Sep. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
The Company and 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 personal computers, flat panel TVs, LED lighting, smart phones, battery packs, consumer and industrial motor controls and power supplies for TVs, computers, servers and telecommunications equipment. The Company conducts its operations primarily in the United States of America (“USA”), Hong Kong, 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, as amended. 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 fiscal year ended June 30, 2016. 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 periods presented have been included in the interim periods. Operating results for the three months ended September 30, 2016 are not necessarily indicative of the results that may be expected for the fiscal year ending June 30, 2017. The condensed consolidated balance sheet at June 30, 2016 is derived from the audited financial statements included in the Company’s Annual Report on Form 10-K for the fiscal year ended June 30, 2016. Reclassification The Company has reclassified certain amounts previously reported in its financial statements to conform to the current presentation. These reclassifications did not have a material impact on our consolidated financial statements. Joint Venture In March 2016, the Company executed an agreement with two strategic investment funds owned by the Municipality of Chongqing, China (the "Chongqing Funds") to form a joint venture for a new state-of-the-art power semiconductor packaging, testing and wafer fabrication facility in Liangjiang New Area of Chongqing (the "Joint Venture"). The initial capitalization of the Joint Venture under the agreement is $330.0 million, which includes cash contribution from the Chongqing Funds and contributions of cash, equipment and intangible assets from the Company. The Company owns 51% and the Chongqing Funds owns 49% of the equity interest of the Joint Venture. The Joint Venture is accounted under the provisions of the consolidation guidance since the Company has controlling financial interest. Use of Estimates The preparation of the condensed 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 condensed consolidated financial statements will be affected. On an ongoing basis, the Company evaluates the estimates, judgments and assumptions including those related to stock rotation returns, price adjustments, allowance for doubtful accounts, inventory reserves, warranty accrual, income taxes, share-based compensation, and useful lives for property, plant and equipment and intangible assets. Fair Value of Financial Instruments The fair value of cash equivalents are based on observable market prices and have been categorized in Level 1 in the fair value hierarchy. Cash equivalents consist primarily of short term bank deposits. The carrying values of financial instruments such as cash and cash equivalents, accounts receivable and accounts payable approximate their carrying values due to their short-term maturities. Impairment of Long-Lived Assets Long-lived assets or asset groups are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset might not be recoverable. Factors that would necessitate an impairment assessment include a significant decline in the observable market value of an asset, a significant change in the extent or manner in which an asset is used, or any other significant adverse change that would indicate that the carrying amount of an asset or group of assets may not be recoverable. Where such factors indicate potential impairment, the recoverability of an asset or asset group is assessed by determining if the carrying value of the asset or asset group exceeds the sum of the projected undiscounted cash flows expected to result from the use and eventual disposition of the assets over the remaining economic life. The impairment loss is measured based on the difference between the carrying amount and the estimated fair value. Comprehensive Income (Loss) Comprehensive income (loss) is defined as the change in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources. The Company's accumulated other comprehensive income (loss) consists of cumulative foreign currency translation adjustments. Total comprehensive income (loss) is presented in the condensed consolidated statements of comprehensive income (loss). Recent Accounting Pronouncements In October 2016, the Financial Accounting Standards Board ("FASB") issued ASU No. 2016-16, "Income Taxes - Intra-Entity Transfers of Assets Other Than Inventory ("ASU 2016-16"). ASU 2016-16 requires entities to recognize income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. The amended guidance is effective for annual reporting periods beginning after December 15, 2018, and interim reporting periods wihin annual periods beginning after December 15, 2019. Early adoption is permitted. The Company is currently evaluating the impact the adoption of ASU 2016-16 will have on its consolidated financial statements. In August 2016, the Financial Accounting Standards Board ("FASB") issued ASU No. 2016-15, "Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments ("ASU 2016-15"). ASU 2016-15 identifies how certain cash receipts and cash payments are presented and classified in the Statement of Cash Flows under Topic 230. ASU 2016-15 is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years, with early adoption permitted. Upon adoption, entities must apply the guidance retrospectively to all periods presented. The Company is currently evaluating the impact the adoption of ASU 2016-15 will have on its consolidated financial statements. In May 2016, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2016-12, "Revenue from Contracts with Customers (Topic 606) - Narrow-Scope Improvements and Practical Expedients." ASU 2016-12 provides additional guidance established by the FASB-IASB Joint Transition Resource Group for Revenue Recognition regarding the implementation of certain aspects of the new revenue recognition guidance. More specifically, the amendment provides additional guidance regarding assessing the collectibility criterion, the presentation of sales taxes and other similar taxes collected from customers, noncash consideration, contract modifications or completed contracts at transition of the new revenue recognition guidance and technical corrections. The effective date is consistent with the effective date of ASU 2014-09. The Company is currently evaluating the impact the adoption of ASU 2016-12 will have on its consolidated financial statements. In April 2016, the FASB issued ASU 2016-10, Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing ("ASU 2016-10"). ASU 2016-10 clarify two aspects of Topic 606: (a) identifying performance obligations; and (b) the licensing implementation guidance. The update is effective for annual periods beginning after December 15, 2017 including interim reporting periods therein. The Company is currently evaluating the impact the adoption of ASU 2016-10 will have on its consolidated financial statements. In March 2016, the FASB issued ASU 2016-09, Improvements to Employee Share-Based Payment Accounting ("ASU 2016-09"). ASU 2016-09 simplifies several aspects of the accounting for employee share-based payment transactions including the accounting for income taxes, forfeitures, and statutory tax withholding requirements, as well as classification of related amounts within the statement of cash flows. This guidance is effective for annual periods beginning after December 15, 2016, and interim periods within those annual periods. Early adoption is permitted. The Company does not expect the adoption of this guidance will have a material impact on its consolidated financial position, results of operations or cash flows. In February 2016, the FASB issued No. 2016-02, Leases ("ASU 2016-02"). This guidance requires a dual approach for lessee accounting under which a lessee will account for leases as finance leases or operating leases. Both finance and operating leases will result in the lessee recognizing a right-of-use asset and a corresponding liability on its balance sheet, with differing methodology for income statement recognition. This guidance is effective for public business entities for fiscal years, and interim periods within those years, beginning after December 15, 2018, and early adoption is permitted. A modified retrospective approach is required for all leases existing or entered into after the beginning of the earliest comparative period in the consolidated financial statements. The Company is currently assessing the impact that adoption of this guidance will have on its consolidated financial statements. In July 2015, the FASB issued No. 2015-11, Inventory - Simplifying the Measurement of Inventory ("ASU 2015-11"). ASU 2015-11 is additional guidance regarding the subsequent measurement of inventory by requiring inventory to be measured at the lower of cost and net realizable value. This guidance is effective for fiscal years and interim periods beginning after December 15, 2016. Early adoption is permitted. The Company does not expect the adoption of this guidance will have a material impact on its consolidated financial position, results of operations or cash flows. In April 2015, the FASB issued ASU No. 2015-03, Interest -Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs. The amendments in this ASU require that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts and the accounting for debt issue costs under IFRS. The recognition and measurement guidance for debt issuance costs are not affected by the amendments in this ASU. ASU 2015-03 is effective for the annual period ending after December 15, 2015, and interim periods within those fiscal years. Early adoption of the amendments in this Update is permitted for financial statements that have not been previously issued. The Company does not expect the adoption of this guidance will have a material impact on its consolidated financial position, results of operations or cash flows. In February 2015, the FASB issued ASU No. 2015-2, “Consolidation (Topic 820): Amendments to the Consolidation Analysis.” ASU 2015-2 provides a revised consolidation model for all reporting entities to use in evaluating whether they should consolidate certain legal entities. All legal entities will be subject to reevaluation under this revised consolidation model. The revised consolidation model, among other things, (i) modifies the evaluation of whether limited partnerships and similar legal entities are VIEs or voting interest entities, (ii) eliminates the presumption that a general partner should consolidate a limited partnership, and (iii) modifies the consolidation analysis of reporting entities that are involved with VIEs through fee arrangements and related party relationships. ASU 2015-2 is effective for fiscal years, and interim reporting periods within those fiscal years, beginning after December 15, 2015. The Company does not expect the adoption of this guidance will have a material impact on its consolidated financial position, results of operations or cash flows. In August 2014, the FASB issued amended standards No. 2014-15, Presentation of Financial Statements - Going Concern ("ASU 2014-15"), to provide guidance about management’s responsibility to evaluate whether there is substantial doubt about an entity’s ability to continue as a going concern and to provide related footnote disclosures requirement. The amendments (1) provide a definition of the term substantial doubt, (2) require an evaluation for each annual and interim reporting period, (3) provide principles for considering the mitigating effect of management’s plans, (4) require certain disclosures when substantial doubt is alleviated as a result of consideration of management’s plans, (5) require an express statement and other disclosures when substantial doubt is not alleviated, and (6) require an assessment for a period of one year after the date that the financial statements are issued (or available to be issued). ASU 2014-15 is effective for the annual period ending after December 15, 2016, and for annual periods and interim periods thereafter. Early adoption is permitted. The Company does not expect the adoption of this guidance will have a material impact on its consolidated financial position, results of operations or cash flows. In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”). The standard provides companies with a single model for use in accounting for revenue arising from contracts with customers and supersedes current revenue recognition guidance, including industry-specific revenue guidance. The core principle of the model is to recognize revenue when control of the goods or services transfers to the customer, as opposed to recognizing revenue when the risks and rewards transfer to the customer under the existing revenue guidance. In August 2015, the FASB issued an accounting standard update for a one-year deferral of the effective date of ASU 2014-09 to annual and interim periods beginning after December 15, 2017 and permits entities to early adopt the standard of ASU 2014-09 for annual and interim reporting periods beginning after December 15, 2016. Companies are permitted to either apply the requirements retrospectively to all prior periods presented, or apply the requirements in the year of adoption, through a cumulative adjustment. The Company is in the process of evaluating the timing of its adoption and the impact of adoption on its consolidated financial statements.

Net Income (Loss) Per Share

3 Months Ended

Sep. 30, 2016

Earnings Per Share [Abstract]

Net Income (Loss) Per Share

Net Income (Loss) Per Common Share Attributable to Alpha and Omega Semiconductor Limited

The following table presents the calculation of basic and diluted net income (loss) per share attributable to common shareholders:



	Three Months Ended September 30,
	2016		2015
	(in thousands, except per share data)
Numerator:
Net income (loss) attributable to Alpha and Omega Semiconductor Limited	$	3,307	$	(1,975	)

Denominator:
Basic:
Weighted average number of common shares used to compute basic net income (loss) per share	23,031		22,698
Diluted:
Weighted average number of common shares used to compute basic net income (loss) per share	23,031		22,698
Effect of potentially dilutive securities:
Stock options, RSUs and ESPP shares	1,382		—
Weighted average number of common shares used to compute diluted net income (loss) per share	24,413		22,698
Net income (loss) per share attributable to Alpha and Omega Semiconductor Limited:
Basic	$	0.14	$	(0.09	)
Diluted	$	0.14	$	(0.09	)

The following potential dilutive securities were excluded from the computation of diluted net income (loss) per share as their effect would have been anti-dilutive:



	Three Months Ended September 30,
	2016	2015
	(in thousands)
Employee stock options and RSUs	247	3,617
ESPP	—	188
Total potential dilutive securities	247	3,805

Concentration of Credit Risk and Significant Customers

3 Months Ended

Sep. 30, 2016

Risks and Uncertainties [Abstract]

Concentration of Credit Risk and Significant Customers

The Company manages its credit risk associated with exposure to distributors and direct customers on outstanding accounts receivable through the application and review of credit approvals, credit ratings and other monitoring procedures. In some instances, the Company also obtains letters of credit from certain customers.

Credit sales, which are mainly on credit terms of 30 to 60 days, are only made to customers who meet the Company's credit requirements, while sales to new customers or customers with low credit ratings are usually made on an advance payment basis. The Company considers its trade accounts receivable to be of good credit quality because its key distributors and direct customers have long-standing business relationships with the Company and the Company has not experienced any significant write-offs of accounts receivable in the past. The Company closely monitors the aging of accounts receivable from its distributors and direct customers, and regularly reviews their financial positions, when available.

Summarized below are individual customers whose revenue or accounts receivable balances were more than 10% of the respective total consolidated amounts:



	Three Months Ended September 30,
Percentage of revenue	2016		2015
Customer A	24.2	%	23.1	%
Customer B	36.5	%	36.0	%
Customer C	13.9	%	14.3	%



	September 30, 2016		June 30, 2016
Percentage of accounts receivable	September 30, 2016		June 30, 2016
Customer A	27.6	%	21.3	%
Customer B	6.9	%	16.7	%
Customer C	35.3	%	27.2	%

Balance Sheet Components

3 Months Ended

Sep. 30, 2016

Balance Sheet Related Disclosures [Abstract]

Balance Sheet Components

Accounts receivable:



	September 30, 2016			June 30, 2016
	(in thousands)
Accounts receivable	$	46,104		$	43,324
Less: Allowance for price adjustments	(19,015		)	(16,700		)
Less: Allowance for doubtful accounts	(30		)	(30		)
Accounts receivable, net	$	27,059		$	26,594

Inventories:



	September 30, 2016		June 30, 2016
	(in thousands)
Raw materials	$	26,352	$	23,982
Work in-process	31,345		32,446
Finished goods	12,321		12,420
	$	70,018	$	68,848

Property, plant and equipment, net:



	September 30, 2016			June 30, 2016
	(in thousands)
Land	$	4,877		$	4,877
Building	4,325			4,323
Manufacturing machinery and equipment	200,778			193,164
Equipment and tooling	13,118			12,289
Computer equipment and software	23,791			23,448
Office furniture and equipment	1,943			1,822
Leasehold improvements	28,825			28,660
	277,657			268,583
Less: Accumulated depreciation	(175,012		)	(168,687		)
	102,645			99,896
Equipment and construction in progress	20,403			16,188
Property, plant and equipment, net	$	123,048		$	116,084

Other long-term assets:



	September 30, 2016		June 30, 2016
	(in thousands)
Prepayments for property and equipment	$	3,404	$	506
Prepayment for others	204		42
Prepaid income tax	5,308		—
Investment in a privately held company	100		100
Office leases deposits	1,342		1,427
Intangible assets	15		15
Goodwill	269		269
	$	10,642	$	2,359

Accrued liabilities:



	September 30, 2016		June 30, 2016
	(in thousands)
Accrued compensation and benefit	$	10,368	$	10,211
Warranty accrual	2,938		1,495
Stock rotation accrual	2,015		1,988
Accrued professional fees	1,936		1,867
Accrued inventory	1,272		918
Accrued facilities related expenses	1,382		1,544
Other accrued expenses	6,066		4,567
	$	25,977	$	22,590

The activities in the warranty accrual, included in accrued liabilities, are as follows:



	Three Months Ended September 30,
	2016			2015
	(in thousands)
Beginning balance	$	1,495		$	1,957
Additions	1,491			305
Utilization	(48		)	(59		)
Ending balance	$	2,938		$	2,203

The activities in the stock rotation accrual, included in accrued liabilities, are as follows:



	Three Months Ended September 30,
	2016			2015
	(in thousands)
Beginning balance	$	1,988		$	1,894
Additions	1,626			1,510
Utilization	(1,599		)	(1,494		)
Ending balance	$	2,015		$	1,910

Other Long-term liabilities:



	September 30, 2016		June 30, 2016
	(in thousands)
Deferred rent	$	680	$	741

Joint Venture

3 Months Ended

Sep. 30, 2016

Equity Method Investments and Joint Ventures [Abstract]

Joint Venture

5. Joint Venture

On March 29, 2016, the Company entered into a joint venture contract (the “JV Agreement”) with two investment funds owned by the Municipality of Chongqing (the “Chongqing Funds”), pursuant to which the Company and the Chongqing Funds formed a joint venture, (the “JV Company”), for the purpose of constructing a power semiconductor packaging, testing and 12-inch wafer fabrication facility in the Liangjiang New Area of Chongqing, China (the “JV Transaction”). The total initial capitalization of the JV Company is $330.0 million (the “Initial Capitalization”), which includes cash contribution from the Chongqing Funds and contributions of cash, equipments and intangible assets from the Company. The Initial Capitalization will be completed in stages commencing on the incorporation of the JV Company. The Company owns 51%, and the Chongqing Funds owns 49%, of the equity interest in the JV Company. If both parties agree that the termination of the JV Company is the best interest of each party or the JV Company is bankrupt or insolvent where either party may terminate early, after paying the debts of the JV Company, the remaining assets of the JV Company shall be paid to the Chongqing Funds to cover the principal of its total paid-in contributions plus interest at 10% simple annual rate prior to distributing the balance of the JV Company's assets to the Company. The Company expects the JV Company to commence its initial production in the first half of fiscal 2018.

The Company began consolidating the financial statements of the JV Company in the quarter ended June 30, 2016. During the quarter ended September 30, 2016, the Chongqing Funds contributed $33.0 million of initial capital in cash and the Company fulfilled its obligation to contribute certain packaging equipments as required by the JV Agreement by transferring the legal titles of such equipment to the JV Company. Within one year from June 30, 2016, the Company expects to contribute certain intangible assets and cash of $10.0 million pursuant to the terms of the JV Agreement.

The changes in total stockholders' equity and noncontrolling interest were as follows (in thousands):



	Total AOS Stockholders' Equity			Noncontrolling Interest			Total Equity
Balance, June 30, 2016	$	242,142		$	(103	)	$	242,039
Contributions from noncontrolling interest	—			33,000			33,000
Exercise of common stock options and release of RSUs	5,988			—			5,988
Reissuance of treasury stock upon exercise of common stock options and release of RSUs	23			—			23
Withholding tax on restricted stock units	(132		)	—			(132		)
Stock-based compensation expense	1,316			—			1,316
Net income (loss)	3,307			(877		)	2,430
Cumulative translation adjustment	91			(21		)	70
Balance, September 30, 2016	$	252,735		$	31,999		$	284,734

Shareholders' Equity and Share-based Compensation

3 Months Ended

Sep. 30, 2016

Share-based Compensation [Abstract]

Shareholders' Equity and Share-based Compensation

Share Repurchase

In April 2015, the Board of Directors approved an increase in the remaining available amount under the Company’s then effective share repurchase program from approximately $17.8 million to $50.0 million. The repurchases may be made from the open market pursuant to a pre-established Rule 10b5-1 trading plan (as amended, the "Repurchase Trading Plan") or through privately negotiated transactions.

In July 2015, the Company completed a Dutch tender offer (the "Tender Offer") in which it purchased 3,296,703 shares of its common shares, at a purchase price of $9.10 per share, for an aggregate purchase price of $30.0 million, excluding fees and expenses relating to the Tender Offer. The Tender Offer was part of the $50.0 million share repurchase program approved by the Board on April 15, 2015. Shares repurchased are accounted for as treasury shares and the total cost of shares repurchased is recorded as a reduction of shareholders' equity.

During the three months ended September 30, 2016, the Company did not repurchased any shares pursuant to the repurchase program. Since the inception of the program in 2010, the Company repurchased an aggregate of 5,723,093 shares from the open market for a total cost of $50.8 million, at an average price of $8.87 per share, excluding fees and related expenses. No repurchased shares have been retired. Of the 5,723,093 repurchased shares, 75,678 shares with a weighted average repurchase price of $12.14 per share, were reissued at an average price of $4.37 per share pursuant to option exercises and vested restricted share units. As of September 30, 2016, $6.4 million remained available under the share repurchase program.

Stock Options

The Company did not grant any stock options during the three months ended September 30, 2016. Options expected to vest are the result of applying the pre-vesting forfeiture rate assumption to total outstanding options.

The following table summarizes the Company's stock option activities for the three months ended September 30, 2016:



					Weighted
			Weighted		Average
			Average		Remaining
	Number of		Exercise Price		Contractual	Aggregate
	Shares		Per Share		Term (in years)	Intrinsic Value
Outstanding at June 30, 2016	1,859,260		$	11.37	4.71	$	5,959,720
Granted	—		$	—
Exercised	(503,236	)	$	11.95		$	3,805,159
Canceled or forfeited	(75,000	)	$	13.43
Outstanding at September 30, 2016	1,281,024		$	11.03	5.00	$	13,693,937
Options vested and expected to vest	1,266,146		$	11.07	4.97	$	13,483,674
Exercisable at September 30, 2016	1,059,449		$	11.75	4.49	$	10,565,183

Restricted Stock Units ("RSU")

The following table summarizes the Company's RSU activities for the three months ended September 30, 2016:



	Number of Restricted Stock Units		Weighted Average Grant Date Fair Value Per Share		Weighted Average Remaining Recognition Period (Years)	Aggregate Intrinsic Value
Nonvested at June 30, 2016	933,063		$	9.18	1.73	$	12,997,568
Granted	54,376		$	19.33
Vested	(30,973	)	$	9.49
Forfeited	(12,575	)	$	11.9
Nonvested at September 30, 2016	943,891		$	9.72	1.57	$	20,501,313
RSUs vested and expected to vest	814,711				1.46	$	17,695,533

The fair value of RSU is estimated based on the market price of the Company's share on the date of grant.

Employee Share Purchase Plan ("ESPP")

The assumptions used to estimate the fair values of common shares issued under the ESPP were as follows:




	Three Months Ended September 30,
	2016
Volatility rate	34.76%
Risk-free interest rate	0.4% - 0.8%
Expected term	1.3 years
Dividend yield	0%

Share-based Compensation Expense

The total share-based compensation expense related to stock options, RSUs and ESPP described above, recognized in the condensed consolidated statements of operations for the periods presented was as follows:



	Three Months Ended September 30,
	2016		2015
	(in thousands)
Cost of goods sold	$	195	$	131
Research and development	360		193
Selling, general and administrative	761		465
	$	1,316	$	789

As of September 30, 2016, total unrecognized compensation cost under the Company's equity plans was $5.4 million, which is expected to be recognized over a weighted-average period of 1.5 years.

Income Taxes	3 Months Ended
Income Taxes	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company recognized income tax expense of approximately $1.2 million and $1.2 million for the three months ended September 30, 2016 and 2015, respectively. The estimated effective tax rate for the three months ended September 30, 2016 was 33.7% compared to (159.5)% for the three months ended September 30, 2015. The changes in the effective tax rate and tax expense between the periods resulted primarily from changes in the mix of earnings in various geographic jurisdictions between the current quarter and the same period of last year. During the quarter ended September 30, 2016, the Company fulfilled its obligations to contribute certain packaging equipment as required by the JV Agreement by transferring the legal titles of such equipment to the JV Company. The Company recorded $6.6 million on both deferred tax assets and prepaid tax asset, which will be amortized to tax expense over the useful life of the assets. As of September 30, 2016, the prepaid tax asset was amortized down to $6.4 million, of which $1.1 million and $5.3 million were included in prepaid and other current assets and other long-term assets on the Company’s balance sheet, respectively. The Company files its income tax returns in the United States and in various foreign jurisdictions. The tax years 2001 to 2016 remain open to examination by U.S. federal and state tax authorities. The tax years 2009 to 2016 remain open to examination by foreign tax authorities. The Company's income tax returns are subject to examinations by the Internal Revenue Service and other tax authorities in various jurisdictions. In accordance with the guidance on the accounting for uncertainty in income taxes, the Company regularly assesses the likelihood of adverse outcomes resulting from these examinations to determine the adequacy of its provision for income taxes. These assessments can require considerable estimates and judgments. As of September 30, 2016, the gross amount of unrecognized tax benefits was approximately $6.8 million, of which $4.4 million, if recognized, would reduce the effective income tax rate in future periods. If the Company's estimate of income tax liabilities proves to be less than the ultimate assessment, then a further charge to expense would be required. If events occur and the payment of these amounts ultimately proves to be unnecessary, the reversal of the liabilities would result in tax benefits being recognized in the period when the Company determines the liabilities are no longer necessary. The Company does not anticipate any material changes to its uncertain tax positions during the next twelve months. On July 27, 2015, in Altera Corp. v. Commissioner, the U.S. Tax Court issued an opinion related to the treatment of share-based compensation expense in an intercompany cost-sharing arrangement. A final decision has yet to be issued by the Tax Court due to other outstanding issues related to the case. At this time, the U.S. Department of the Treasury has not withdrawn the requirement to include share-based compensation from its regulations. Due to the uncertainty surrounding the status of the current regulations, questions related to the scope of potential benefits, and the risk of the Tax Court’s decision being overturned upon appeal, the Company has not recorded any benefit as of September 30, 2016. The Company will continue to monitor ongoing developments and potential impacts to its financial statements.

Segment and Geographic Information

3 Months Ended

Sep. 30, 2016

Segment Reporting [Abstract]

Segment and Geographic Information

The Company is organized as, and operates in, one operating segment: the design, development and supply of power semiconductor products for computing, consumer electronics, communication and industrial applications. The chief operating decision-maker is the Chief Executive Officer. The financial information presented to the Company's Chief Executive Officer is on a consolidated basis, accompanied by information about revenue by customer and geographic region, for purposes of evaluating financial performance and allocating resources. The Company has one business segment, and there are no segment managers who are held accountable for operations, operating results and plans for products or components below the consolidated unit level. Accordingly, the Company reports as a single operating segment.

The Company sells its products primarily to distributors in the Asia Pacific region, who in turn sell these products to end customers. Because the Company's distributors sell their products to end customers which may have a global presence, revenue by geographical location is not necessarily representative of the geographical distribution of sales to end user markets.

The revenue by geographical location in the following tables is based on the country or region to which the products were shipped to:



	Three Months Ended September 30,
	2016		2015
	(in thousands)
Hong Kong	$	82,835	$	70,453
China	12,442		9,016
South Korea	366		658
United States	894		717
Other Countries	825		595
	$	97,362	$	81,439

The following is a summary of revenue by product type:



	Three Months Ended September 30,
	2016		2015
	(in thousands)
Power discrete	$	71,428	$	59,912
Power IC	22,998		17,514
Packaging and testing services	2,936		4,013
	$	97,362	$	81,439

Long-lived assets, net consisting of property, plant and equipment, by geographical area are as follows:



	September 30, 2016		June 30, 2016
	(in thousands)
China	$	69,567	$	64,272
United States	52,859		51,214
Other Countries	622		598
	$	123,048	$	116,084

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e8981-108599

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 41
-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e9038-108599

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e8971-108599

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e8595-108599

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e8380-108599

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e8933-108599

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 26
-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e8844-108599

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 35
-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e8984-108599

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 40
-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e9031-108599

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e9054-108599

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e8538-108599

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 29
-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e8864-108599

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 31
-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e8924-108599

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-URI http://asc.fasb.org/extlink&oid=51669610&loc=d3e8906-108599

+ Details

Commitments and Contingencies	3 Months Ended
Commitments and Contingencies	Sep. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Purchase Commitments As of September 30, 2016 and June 30, 2016, the Company had approximately $38.6 million and $39.6 million, respectively, of outstanding purchase commitments primarily for purchases of semiconductor raw materials, wafers, spare parts and packaging and testing services, and approximately $6.2 million and $6.6 million, respectively, of capital commitments for the purchase of property and equipment. Contingencies and Indemnities The Company is currently not a party to any pending material legal proceedings. The Company has in the past, and may from time to time in the future, become involved in legal proceedings arising from the normal course of business activities. The semiconductor industry is characterized by frequent claims and litigation, including claims regarding patent and other intellectual property rights as well as improper hiring practices. Irrespective of the validity of such claims, the Company could incur significant costs in the defense of such claims and suffer adverse effects on its operations. The Company is a party to a variety of agreements that it has contracted with various third parties. Pursuant to these agreements, the Company may be obligated to indemnify another party to such an agreement with respect to certain matters. Typically, these obligations arise in the context of contracts entered into by the Company, under which the Company customarily agrees to hold the other party harmless against losses arising from a breach of representations and covenants related to such matters as title to assets sold, certain intellectual property rights, specified environmental matters and certain income taxes. In these circumstances, payment by the Company is customarily conditioned on the other party making a claim pursuant to the procedures specified in the particular contract, which procedures typically allow the Company to challenge the other party's claim. Further, the Company's obligations under these agreements may be limited in time and/or amount, and in some instances, the Company may have recourse against third parties for certain payments made by it under these agreements. The Company has not historically paid or recorded any material indemnifications and no accrual has been made at September 30, 2016 and June 30, 2016. The Company has agreed to indemnify its directors and certain employees as permitted by law and pursuant to its bye-laws, and has entered into indemnification agreements with its directors and executive officers. The Company has not recorded a liability associated with these indemnification arrangements, as it historically has not incurred any material costs associated with such indemnification obligations. Costs associated with such indemnification obligations may be mitigated by insurance coverage that the Company maintains. However, such insurance may not cover any, or may cover only a portion of, the amounts the Company may be required to pay. In addition, the Company may not be able to maintain such insurance coverage in the future. Joint Venture In March 2016, the Company executed an agreement with two strategic investment funds owned by the Municipality of Chongqing, China to form a joint venture for a new state-of-the-art power semiconductor packaging, testing and wafer fabrication facility in Liangjiang New Area of Chongqing (the "Joint Venture"). The initial capitalization of the Joint Venture under the agreement is $330.0 million, which includes cash contribution from the Chongqing Funds and contributions of cash, equipments and intangible assets from the Company. The Company owns 51% and the Chongqing Funds owns 49% of the equity interest of the Joint Venture. The Joint Venture is accounted under the provisions of the consolidation guidance since the Company has controlling financial interest. The Joint Venture is expected to commence its initial packaging production in the first half of fiscal 2018. Within one year from June 30, 2016, the Company is expected to contribute cash of $10.0 million and certain intangible assets. Over the long term, the Joint Venture plans to construct a 12-inch wafer fabrication facility for the production of power semiconductors.

The Company and Significant Accounting Policies (Policies)	3 Months Ended
	Sep. 30, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Preparation	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, as amended. 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 fiscal year ended June 30, 2016. 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 periods presented have been included in the interim periods. Operating results for the three months ended September 30, 2016 are not necessarily indicative of the results that may be expected for the fiscal year ending June 30, 2017. The condensed consolidated balance sheet at June 30, 2016 is derived from the audited financial statements included in the Company’s Annual Report on Form 10-K for the fiscal year ended June 30, 2016.
Reclassification	Reclassification The Company has reclassified certain amounts previously reported in its financial statements to conform to the current presentation. These reclassifications did not have a material impact on our consolidated financial statements.
Use of Estimates	Use of Estimates The preparation of the condensed 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 condensed consolidated financial statements will be affected. On an ongoing basis, the Company evaluates the estimates, judgments and assumptions including those related to stock rotation returns, price adjustments, allowance for doubtful accounts, inventory reserves, warranty accrual, income taxes, share-based compensation, and useful lives for property, plant and equipment and intangible assets.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The fair value of cash equivalents are based on observable market prices and have been categorized in Level 1 in the fair value hierarchy. Cash equivalents consist primarily of short term bank deposits. The carrying values of financial instruments such as cash and cash equivalents, accounts receivable and accounts payable approximate their carrying values due to their short-term maturities.
Impairment of Long-Lived Assets [Policy Text Block]	Impairment of Long-Lived Assets Long-lived assets or asset groups are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset might not be recoverable. Factors that would necessitate an impairment assessment include a significant decline in the observable market value of an asset, a significant change in the extent or manner in which an asset is used, or any other significant adverse change that would indicate that the carrying amount of an asset or group of assets may not be recoverable. Where such factors indicate potential impairment, the recoverability of an asset or asset group is assessed by determining if the carrying value of the asset or asset group exceeds the sum of the projected undiscounted cash flows expected to result from the use and eventual disposition of the assets over the remaining economic life. The impairment loss is measured based on the difference between the carrying amount and the estimated fair value.
Comprehensive Income (Loss)	Comprehensive Income (Loss) Comprehensive income (loss) is defined as the change in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources. The Company's accumulated other comprehensive income (loss) consists of cumulative foreign currency translation adjustments. Total comprehensive income (loss) is presented in the condensed consolidated statements of comprehensive income (loss).
Recent Accounting Pronouncements	Recent Accounting Pronouncements In October 2016, the Financial Accounting Standards Board ("FASB") issued ASU No. 2016-16, "Income Taxes - Intra-Entity Transfers of Assets Other Than Inventory ("ASU 2016-16"). ASU 2016-16 requires entities to recognize income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. The amended guidance is effective for annual reporting periods beginning after December 15, 2018, and interim reporting periods wihin annual periods beginning after December 15, 2019. Early adoption is permitted. The Company is currently evaluating the impact the adoption of ASU 2016-16 will have on its consolidated financial statements. In August 2016, the Financial Accounting Standards Board ("FASB") issued ASU No. 2016-15, "Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments ("ASU 2016-15"). ASU 2016-15 identifies how certain cash receipts and cash payments are presented and classified in the Statement of Cash Flows under Topic 230. ASU 2016-15 is effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years, with early adoption permitted. Upon adoption, entities must apply the guidance retrospectively to all periods presented. The Company is currently evaluating the impact the adoption of ASU 2016-15 will have on its consolidated financial statements. In May 2016, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2016-12, "Revenue from Contracts with Customers (Topic 606) - Narrow-Scope Improvements and Practical Expedients." ASU 2016-12 provides additional guidance established by the FASB-IASB Joint Transition Resource Group for Revenue Recognition regarding the implementation of certain aspects of the new revenue recognition guidance. More specifically, the amendment provides additional guidance regarding assessing the collectibility criterion, the presentation of sales taxes and other similar taxes collected from customers, noncash consideration, contract modifications or completed contracts at transition of the new revenue recognition guidance and technical corrections. The effective date is consistent with the effective date of ASU 2014-09. The Company is currently evaluating the impact the adoption of ASU 2016-12 will have on its consolidated financial statements. In April 2016, the FASB issued ASU 2016-10, Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing ("ASU 2016-10"). ASU 2016-10 clarify two aspects of Topic 606: (a) identifying performance obligations; and (b) the licensing implementation guidance. The update is effective for annual periods beginning after December 15, 2017 including interim reporting periods therein. The Company is currently evaluating the impact the adoption of ASU 2016-10 will have on its consolidated financial statements. In March 2016, the FASB issued ASU 2016-09, Improvements to Employee Share-Based Payment Accounting ("ASU 2016-09"). ASU 2016-09 simplifies several aspects of the accounting for employee share-based payment transactions including the accounting for income taxes, forfeitures, and statutory tax withholding requirements, as well as classification of related amounts within the statement of cash flows. This guidance is effective for annual periods beginning after December 15, 2016, and interim periods within those annual periods. Early adoption is permitted. The Company does not expect the adoption of this guidance will have a material impact on its consolidated financial position, results of operations or cash flows. In February 2016, the FASB issued No. 2016-02, Leases ("ASU 2016-02"). This guidance requires a dual approach for lessee accounting under which a lessee will account for leases as finance leases or operating leases. Both finance and operating leases will result in the lessee recognizing a right-of-use asset and a corresponding liability on its balance sheet, with differing methodology for income statement recognition. This guidance is effective for public business entities for fiscal years, and interim periods within those years, beginning after December 15, 2018, and early adoption is permitted. A modified retrospective approach is required for all leases existing or entered into after the beginning of the earliest comparative period in the consolidated financial statements. The Company is currently assessing the impact that adoption of this guidance will have on its consolidated financial statements. In July 2015, the FASB issued No. 2015-11, Inventory - Simplifying the Measurement of Inventory ("ASU 2015-11"). ASU 2015-11 is additional guidance regarding the subsequent measurement of inventory by requiring inventory to be measured at the lower of cost and net realizable value. This guidance is effective for fiscal years and interim periods beginning after December 15, 2016. Early adoption is permitted. The Company does not expect the adoption of this guidance will have a material impact on its consolidated financial position, results of operations or cash flows. In April 2015, the FASB issued ASU No. 2015-03, Interest -Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs. The amendments in this ASU require that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts and the accounting for debt issue costs under IFRS. The recognition and measurement guidance for debt issuance costs are not affected by the amendments in this ASU. ASU 2015-03 is effective for the annual period ending after December 15, 2015, and interim periods within those fiscal years. Early adoption of the amendments in this Update is permitted for financial statements that have not been previously issued. The Company does not expect the adoption of this guidance will have a material impact on its consolidated financial position, results of operations or cash flows. In February 2015, the FASB issued ASU No. 2015-2, “Consolidation (Topic 820): Amendments to the Consolidation Analysis.” ASU 2015-2 provides a revised consolidation model for all reporting entities to use in evaluating whether they should consolidate certain legal entities. All legal entities will be subject to reevaluation under this revised consolidation model. The revised consolidation model, among other things, (i) modifies the evaluation of whether limited partnerships and similar legal entities are VIEs or voting interest entities, (ii) eliminates the presumption that a general partner should consolidate a limited partnership, and (iii) modifies the consolidation analysis of reporting entities that are involved with VIEs through fee arrangements and related party relationships. ASU 2015-2 is effective for fiscal years, and interim reporting periods within those fiscal years, beginning after December 15, 2015. The Company does not expect the adoption of this guidance will have a material impact on its consolidated financial position, results of operations or cash flows. In August 2014, the FASB issued amended standards No. 2014-15, Presentation of Financial Statements - Going Concern ("ASU 2014-15"), to provide guidance about management’s responsibility to evaluate whether there is substantial doubt about an entity’s ability to continue as a going concern and to provide related footnote disclosures requirement. The amendments (1) provide a definition of the term substantial doubt, (2) require an evaluation for each annual and interim reporting period, (3) provide principles for considering the mitigating effect of management’s plans, (4) require certain disclosures when substantial doubt is alleviated as a result of consideration of management’s plans, (5) require an express statement and other disclosures when substantial doubt is not alleviated, and (6) require an assessment for a period of one year after the date that the financial statements are issued (or available to be issued). ASU 2014-15 is effective for the annual period ending after December 15, 2016, and for annual periods and interim periods thereafter. Early adoption is permitted. The Company does not expect the adoption of this guidance will have a material impact on its consolidated financial position, results of operations or cash flows. In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”). The standard provides companies with a single model for use in accounting for revenue arising from contracts with customers and supersedes current revenue recognition guidance, including industry-specific revenue guidance. The core principle of the model is to recognize revenue when control of the goods or services transfers to the customer, as opposed to recognizing revenue when the risks and rewards transfer to the customer under the existing revenue guidance. In August 2015, the FASB issued an accounting standard update for a one-year deferral of the effective date of ASU 2014-09 to annual and interim periods beginning after December 15, 2017 and permits entities to early adopt the standard of ASU 2014-09 for annual and interim reporting periods beginning after December 15, 2016. Companies are permitted to either apply the requirements retrospectively to all prior periods presented, or apply the requirements in the year of adoption, through a cumulative adjustment. The Company is in the process of evaluating the timing of its adoption and the impact of adoption on its consolidated financial statements.
Concentration of Credit Risk	The Company manages its credit risk associated with exposure to distributors and direct customers on outstanding accounts receivable through the application and review of credit approvals, credit ratings and other monitoring procedures. In some instances, the Company also obtains letters of credit from certain customers. Credit sales, which are mainly on credit terms of 30 to 60 days, are only made to customers who meet the Company's credit requirements, while sales to new customers or customers with low credit ratings are usually made on an advance payment basis. The Company considers its trade accounts receivable to be of good credit quality because its key distributors and direct customers have long-standing business relationships with the Company and the Company has not experienced any significant write-offs of accounts receivable in the past. The Company closely monitors the aging of accounts receivable from its distributors and direct customers, and regularly reviews their financial positions, when available.

Net Income (Loss) Per Share (Tables)

3 Months Ended

Sep. 30, 2016

Earnings Per Share [Abstract]

Schedule of Earnings Per Share, Basic and Diluted

The following table presents the calculation of basic and diluted net income (loss) per share attributable to common shareholders:



	Three Months Ended September 30,
	2016		2015
	(in thousands, except per share data)
Numerator:
Net income (loss) attributable to Alpha and Omega Semiconductor Limited	$	3,307	$	(1,975	)

Denominator:
Basic:
Weighted average number of common shares used to compute basic net income (loss) per share	23,031		22,698
Diluted:
Weighted average number of common shares used to compute basic net income (loss) per share	23,031		22,698
Effect of potentially dilutive securities:
Stock options, RSUs and ESPP shares	1,382		—
Weighted average number of common shares used to compute diluted net income (loss) per share	24,413		22,698
Net income (loss) per share attributable to Alpha and Omega Semiconductor Limited:
Basic	$	0.14	$	(0.09	)
Diluted	$	0.14	$	(0.09	)

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share

The following potential dilutive securities were excluded from the computation of diluted net income (loss) per share as their effect would have been anti-dilutive:



	Three Months Ended September 30,
	2016	2015
	(in thousands)
Employee stock options and RSUs	247	3,617
ESPP	—	188
Total potential dilutive securities	247	3,805

Concentration of Credit Risk and Significant Customers (Tables)

3 Months Ended

Sep. 30, 2016

Risks and Uncertainties [Abstract]

Schedules of Concentration of Risk, by Risk Factor

Summarized below are individual customers whose revenue or accounts receivable balances were more than 10% of the respective total consolidated amounts:



	Three Months Ended September 30,
Percentage of revenue	2016		2015
Customer A	24.2	%	23.1	%
Customer B	36.5	%	36.0	%
Customer C	13.9	%	14.3	%



	September 30, 2016		June 30, 2016
Percentage of accounts receivable	September 30, 2016		June 30, 2016
Customer A	27.6	%	21.3	%
Customer B	6.9	%	16.7	%
Customer C	35.3	%	27.2	%

Balance Sheet Components (Tables)

3 Months Ended

Sep. 30, 2016

Balance Sheet Related Disclosures [Abstract]

Schedule of Accounts, Notes, Loans and Financing Receivable

Accounts receivable:



	September 30, 2016			June 30, 2016
	(in thousands)
Accounts receivable	$	46,104		$	43,324
Less: Allowance for price adjustments	(19,015		)	(16,700		)
Less: Allowance for doubtful accounts	(30		)	(30		)
Accounts receivable, net	$	27,059		$	26,594

Schedule of Inventory, Current

Inventories:



	September 30, 2016		June 30, 2016
	(in thousands)
Raw materials	$	26,352	$	23,982
Work in-process	31,345		32,446
Finished goods	12,321		12,420
	$	70,018	$	68,848

Property, Plant and Equipment

Property, plant and equipment, net:



	September 30, 2016			June 30, 2016
	(in thousands)
Land	$	4,877		$	4,877
Building	4,325			4,323
Manufacturing machinery and equipment	200,778			193,164
Equipment and tooling	13,118			12,289
Computer equipment and software	23,791			23,448
Office furniture and equipment	1,943			1,822
Leasehold improvements	28,825			28,660
	277,657			268,583
Less: Accumulated depreciation	(175,012		)	(168,687		)
	102,645			99,896
Equipment and construction in progress	20,403			16,188
Property, plant and equipment, net	$	123,048		$	116,084

Schedule of Other Assets, Noncurrent

Other long-term assets:



	September 30, 2016		June 30, 2016
	(in thousands)
Prepayments for property and equipment	$	3,404	$	506
Prepayment for others	204		42
Prepaid income tax	5,308		—
Investment in a privately held company	100		100
Office leases deposits	1,342		1,427
Intangible assets	15		15
Goodwill	269		269
	$	10,642	$	2,359

Schedule of Accrued Liabilities

Accrued liabilities:



	September 30, 2016		June 30, 2016
	(in thousands)
Accrued compensation and benefit	$	10,368	$	10,211
Warranty accrual	2,938		1,495
Stock rotation accrual	2,015		1,988
Accrued professional fees	1,936		1,867
Accrued inventory	1,272		918
Accrued facilities related expenses	1,382		1,544
Other accrued expenses	6,066		4,567
	$	25,977	$	22,590

Schedule of Product Warranty Liability

The activities in the warranty accrual, included in accrued liabilities, are as follows:



	Three Months Ended September 30,
	2016			2015
	(in thousands)
Beginning balance	$	1,495		$	1,957
Additions	1,491			305
Utilization	(48		)	(59		)
Ending balance	$	2,938		$	2,203

Stock Rotation Accrual

The activities in the stock rotation accrual, included in accrued liabilities, are as follows:



	Three Months Ended September 30,
	2016			2015
	(in thousands)
Beginning balance	$	1,988		$	1,894
Additions	1,626			1,510
Utilization	(1,599		)	(1,494		)
Ending balance	$	2,015		$	1,910

Schedule of Other Noncurrent Liabilities

Other Long-term liabilities:



	September 30, 2016		June 30, 2016
	(in thousands)
Deferred rent	$	680	$	741

Joint Venture (Tables)

3 Months Ended

Sep. 30, 2016

Equity Method Investments and Joint Ventures [Abstract]

Schedule of Stockholders Equity

The changes in total stockholders' equity and noncontrolling interest were as follows (in thousands):



	Total AOS Stockholders' Equity			Noncontrolling Interest			Total Equity
Balance, June 30, 2016	$	242,142		$	(103	)	$	242,039
Contributions from noncontrolling interest	—			33,000			33,000
Exercise of common stock options and release of RSUs	5,988			—			5,988
Reissuance of treasury stock upon exercise of common stock options and release of RSUs	23			—			23
Withholding tax on restricted stock units	(132		)	—			(132		)
Stock-based compensation expense	1,316			—			1,316
Net income (loss)	3,307			(877		)	2,430
Cumulative translation adjustment	91			(21		)	70
Balance, September 30, 2016	$	252,735		$	31,999		$	284,734

Shareholders' Equity and Share-based Compensation (Tables)

3 Months Ended

Sep. 30, 2016

Share-based Compensation [Abstract]

Summary of Stock Option Activities

Stock Options

The Company did not grant any stock options during the three months ended September 30, 2016. Options expected to vest are the result of applying the pre-vesting forfeiture rate assumption to total outstanding options.

The following table summarizes the Company's stock option activities for the three months ended September 30, 2016:



					Weighted
			Weighted		Average
			Average		Remaining
	Number of		Exercise Price		Contractual	Aggregate
	Shares		Per Share		Term (in years)	Intrinsic Value
Outstanding at June 30, 2016	1,859,260		$	11.37	4.71	$	5,959,720
Granted	—		$	—
Exercised	(503,236	)	$	11.95		$	3,805,159
Canceled or forfeited	(75,000	)	$	13.43
Outstanding at September 30, 2016	1,281,024		$	11.03	5.00	$	13,693,937
Options vested and expected to vest	1,266,146		$	11.07	4.97	$	13,483,674
Exercisable at September 30, 2016	1,059,449		$	11.75	4.49	$	10,565,183

Restricted Stock Units Activity

Restricted Stock Units ("RSU")

The following table summarizes the Company's RSU activities for the three months ended September 30, 2016:



	Number of Restricted Stock Units		Weighted Average Grant Date Fair Value Per Share		Weighted Average Remaining Recognition Period (Years)	Aggregate Intrinsic Value
Nonvested at June 30, 2016	933,063		$	9.18	1.73	$	12,997,568
Granted	54,376		$	19.33
Vested	(30,973	)	$	9.49
Forfeited	(12,575	)	$	11.9
Nonvested at September 30, 2016	943,891		$	9.72	1.57	$	20,501,313
RSUs vested and expected to vest	814,711				1.46	$	17,695,533

The fair value of RSU is estimated based on the market price of the Company's share on the date of grant.

Schedule of Share-based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions [Table Text Block]

Employee Share Purchase Plan ("ESPP")

The assumptions used to estimate the fair values of common shares issued under the ESPP were as follows:




	Three Months Ended September 30,
	2016
Volatility rate	34.76%
Risk-free interest rate	0.4% - 0.8%
Expected term	1.3 years
Dividend yield	0%

Share-based Compensation, Allocation of Recognized Period Costs

Share-based Compensation Expense

The total share-based compensation expense related to stock options, RSUs and ESPP described above, recognized in the condensed consolidated statements of operations for the periods presented was as follows:



	Three Months Ended September 30,
	2016		2015
	(in thousands)
Cost of goods sold	$	195	$	131
Research and development	360		193
Selling, general and administrative	761		465
	$	1,316	$	789

Segment and Geographic Information (Tables)

3 Months Ended

Sep. 30, 2016

Segment Reporting [Abstract]

Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas

Long-lived assets, net consisting of property, plant and equipment, by geographical area are as follows:



	September 30, 2016		June 30, 2016
	(in thousands)
China	$	69,567	$	64,272
United States	52,859		51,214
Other Countries	622		598
	$	123,048	$	116,084

The revenue by geographical location in the following tables is based on the country or region to which the products were shipped to:



	Three Months Ended September 30,
	2016		2015
	(in thousands)
Hong Kong	$	82,835	$	70,453
China	12,442		9,016
South Korea	366		658
United States	894		717
Other Countries	825		595
	$	97,362	$	81,439

Revenue from External Customers by Products and Services

The following is a summary of revenue by product type:



	Three Months Ended September 30,
	2016		2015
	(in thousands)
Power discrete	$	71,428	$	59,912
Power IC	22,998		17,514
Packaging and testing services	2,936		4,013
	$	97,362	$	81,439

The Company and Significant Accounting Policies Joint Venture (Details) - Facility in Liangjiang New Area of Chongqing (the 'Joint Venture') [Member] - USD ($) $ in Millions	1 Months Ended
	Mar. 31, 2016	Mar. 29, 2016
Corporate Joint Venture [Member]
Initial capitalization of joint venture		$ 330.0
Chongqing Funds [Member]
Subsidiary or Equity Method Investee, Cumulative Percentage Ownership after All Transactions	49.00%
Parent Company [Member]
Subsidiary or Equity Method Investee, Cumulative Percentage Ownership after All Transactions	51.00%

Net Income (Loss) Per Share - Basic and Diluted Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Numerator:
Net income (loss) attributable to Alpha and Omega Semiconductor Limited	$ 3,307	$ (1,975)
Basic:
Weighted average number of common shares used to compute basic net income (loss) per share	23,031	22,698
Effect of potentially dilutive securities:
Stock options, RSUs and ESPP shares	1,382	0
Weighted average number of common shares used to compute diluted net income (loss) per share	24,413	22,698
Net income (loss) per share attributable to Alpha and Omega Semiconductor Limited:
Basic (in dollars per share)	$ 0.14	$ (0.09)
Diluted (in dollars per share)	$ 0.14	$ (0.09)

Net Income (Loss) Per Share - Potential Dilutive Shares (Details) - shares shares in Thousands	3 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities (in shares)	247	3,805
Employee stock options and RSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities (in shares)	247	3,617
ESPP
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potential dilutive securities (in shares)	0	188

Concentration of Credit Risk and Significant Customers - (Details)	3 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Sep. 30, 2015
Minimum [Member]
Concentration Risk
Terms of credit sales, (in days)	30 days
Maximum [Member]
Concentration Risk
Terms of credit sales, (in days)	60 days
Customer A \| Sales Revenue, Goods, Net \| Customer Concentration Risk
Concentration Risk
Customers greater than 10% of total	24.20%		23.10%
Customer A \| Accounts Receivable \| Customer Concentration Risk
Concentration Risk
Customers greater than 10% of total	27.60%	21.30%
Customer B \| Sales Revenue, Goods, Net \| Customer Concentration Risk
Concentration Risk
Customers greater than 10% of total	36.50%		36.00%
Customer B \| Accounts Receivable \| Customer Concentration Risk
Concentration Risk
Customers greater than 10% of total	6.90%	16.70%
Customer C \| Sales Revenue, Goods, Net \| Customer Concentration Risk
Concentration Risk
Customers greater than 10% of total	13.90%		14.30%
Customer C \| Accounts Receivable \| Customer Concentration Risk
Concentration Risk
Customers greater than 10% of total	35.30%	27.20%

Balance Sheet Components - Accounts receivable (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Jun. 30, 2016
Balance Sheet Related Disclosures [Abstract]
Accounts receivable	$ 46,104	$ 43,324
Less: Allowance for price adjustments	(19,015)	(16,700)
Less: Allowance for doubtful accounts	(30)	(30)
Accounts receivable, net	$ 27,059	$ 26,594

Balance Sheet Components - Inventories (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Jun. 30, 2016
Balance Sheet Related Disclosures [Abstract]
Raw materials	$ 26,352	$ 23,982
Work in-process	31,345	32,446
Finished goods	12,321	12,420
Inventory, net	$ 70,018	$ 68,848

Balance Sheet Components - Property, plant, and equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Jun. 30, 2016
Property, Plant and Equipment [Line Items]
Property, plant, and equipment excluding equipment and construction In progress, gross	$ 277,657	$ 268,583
Less: Accumulated depreciation	(175,012)	(168,687)
Property, plant and equipment excluding equipment and construction in progress, net	102,645	99,896
Equipment and construction in progress	20,403	16,188
Property, plant and equipment, net	123,048	116,084
Land
Property, Plant and Equipment [Line Items]
Property, plant, and equipment excluding equipment and construction In progress, gross	4,877	4,877
Building
Property, Plant and Equipment [Line Items]
Property, plant, and equipment excluding equipment and construction In progress, gross	4,325	4,323
Manufacturing machinery and equipment
Property, Plant and Equipment [Line Items]
Property, plant, and equipment excluding equipment and construction In progress, gross	200,778	193,164
Equipment and tooling
Property, Plant and Equipment [Line Items]
Property, plant, and equipment excluding equipment and construction In progress, gross	13,118	12,289
Computer equipment and software
Property, Plant and Equipment [Line Items]
Property, plant, and equipment excluding equipment and construction In progress, gross	23,791	23,448
Office furniture and equipment
Property, Plant and Equipment [Line Items]
Property, plant, and equipment excluding equipment and construction In progress, gross	1,943	1,822
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant, and equipment excluding equipment and construction In progress, gross	$ 28,825	$ 28,660

Balance Sheet Components - Other long term assets (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Jun. 30, 2016
Balance Sheet Related Disclosures [Abstract]
Prepayments for property and equipment	$ 3,404	$ 506
Prepayment for others	204	42
Prepaid income tax	5,308	0
Investment in a privately held company	100	100
Office leases deposits	1,342	1,427
Intangible assets	15	15
Goodwill	269	269
Other long-term assets	$ 10,642	$ 2,359

Balance Sheet Components - Accrued liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Jun. 30, 2016	Sep. 30, 2015	Jun. 30, 2015
Balance Sheet Related Disclosures [Abstract]
Accrued compensation and benefit	$ 10,368	$ 10,211
Warranty accrual	2,938	1,495	$ 2,203	$ 1,957
Stock rotation accrual	2,015	1,988	$ 1,910	$ 1,894
Accrued professional fees	1,936	1,867
Accrued inventory	1,272	918
Accrued facilities related expenses	1,382	1,544
Other accrued expenses	6,066	4,567
Accrued liabilities	$ 25,977	$ 22,590

Balance Sheet Components - Product Warranty Accrual (Details) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Movement in Standard and Extended Product Warranty, Increase (Decrease) [Roll Forward]
Beginning balance	$ 1,495	$ 1,957
Additions	1,491	305
Utilization	(48)	(59)
Ending balance	$ 2,938	$ 2,203

Balance Sheet Components - Stock Rotation Accrual (Details) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Stock Rotation Accrual Increae (Decrease) [Roll Forward]
Beginning balance	$ 1,988	$ 1,894
Additions	1,626	1,510
Utilization	(1,599)	(1,494)
Ending balance	$ 2,015	$ 1,910

Balance Sheet Components - Other Long Term Liability (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Jun. 30, 2016
Balance Sheet Related Disclosures [Abstract]
Deferred rent	$ 680	$ 741
Other long term liabilities	$ 680	$ 741

Joint Venture - Narrative (Details) - Facility in Liangjiang New Area of Chongqing (the 'Joint Venture') [Member] - USD ($) $ in Millions	1 Months Ended	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Sep. 30, 2016	Jun. 30, 2017	Mar. 29, 2016
Interest rate to concontrolling interest if joint venture is early terminated and liquidated		10.00%
Corporate Joint Venture [Member]
Initial capitalization of joint venture				$ 330.0
Parent Company [Member]
Percent ownership in joint venture	51.00%
Chongqing Funds [Member]
Percent ownership in joint venture	49.00%
Payments to acquire interest in joint venture		$ 33.0
Scenario, Forecast [Member]
Consideration transferred to acquire interest in joint venture			$ 10.0

Joint Venture - Changes in Total Stockholders' Equity (Details) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Beginning balance	$ 242,039
Contributions from noncontrolling interest	33,000
Exercise of common stock options and release of RSUs	5,988
Reissuance of treasury stock upon exercise of common stock options and release of RSUs	23
Withholding tax on restricted stock units	(132)
Stock-based compensation expense	1,316
Net income (loss)	2,430	$ (1,975)
Cumulative translation adjustment	70
Ending balance	284,734
Parent [Member]
Beginning balance	242,142
Exercise of common stock options and release of RSUs	5,988
Reissuance of treasury stock upon exercise of common stock options and release of RSUs	23
Withholding tax on restricted stock units	(132)
Stock-based compensation expense	1,316
Net income (loss)	3,307
Cumulative translation adjustment	91
Ending balance	252,735
Noncontrolling Interest [Member]
Beginning balance	(103)
Contributions from noncontrolling interest	33,000
Net income (loss)	(877)
Cumulative translation adjustment	(21)
Ending balance	$ 31,999

Shareholders' Equity and Share-based Compensation - Shares Repurchase (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended	71 Months Ended
	Jul. 07, 2015	Sep. 30, 2016	Sep. 30, 2016	Jun. 07, 2015	Apr. 30, 2015	Mar. 31, 2015
Class of Stock [Line Items]
Shares Repurchase Program Remaining Balance		$ 6.4	$ 6.4		$ 50.0	$ 17.8
Treasury Stock, Shares, Acquired		0	5,723,093
Treasury Stock, Value, Acquired, Cost Method			$ 50.8
Treasury stock acquired, average price per share (in dollars per share)			$ 8.87
Treasury Stock, Shares, Retired			0
Treasury Stock Reissued, Average Price Per Share			$ 4.37
Treasury Stock Reissued
Class of Stock [Line Items]
Treasury stock acquired, average price per share (in dollars per share)			$ 12.14
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures (in shares)			75,678
Dutch Auction Tender Offer [Member] \| Common Stock [Member]
Class of Stock [Line Items]
Share repurchase program, authorized amount (USD in Millions)				$ 30.0
Treasury Stock, Shares, Acquired	3,296,703
Treasury stock acquired, average price per share (in dollars per share)	$ 9.10

Shareholders' Equity and Share-based Compensation - Share-based Compensation (Details) - USD ($)	3 Months Ended		71 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Treasury Stock, Shares, Acquired	0		5,723,093
Options, Weighted-Average Remaining Contractual Life (in years)	5 years	4 years 8 months 16 days
Options vested and expected to vest, Number Outstanding (in shares)	1,266,146		1,266,146
Options vested and expected to vest, Weighted Average Exercise Price (in dollars per share)	$ 11.07		$ 11.07
Options vested and expected to vest, Weighted Average Remaining Contractual Life (in years)	4 years 11 months 19 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value	$ 13,483,674		$ 13,483,674
Options, Number Exercisable (in shares)	1,059,449		1,059,449
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$ 11.75		$ 11.75
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term	4 years 5 months 27 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value	$ 10,565,183		$ 10,565,183
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding at June 30, 2016	1,859,260
Granted (in shares)	0
Exercised (in shares)	(503,236)
Canceled or forfeited (in shares)	(75,000)
Outstanding at September 30, 2016	1,281,024	1,859,260	1,281,024
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding at June 30, 2016 (in dollars per share)	$ 11.37
Granted (in dollars per share)	0
Exercised (in dollars per share)	11.95
Canceled or forfeited (in dollars per share)	13.43
Outstanding at September 30, 2016 (in dollars per share)	$ 11.03	$ 11.37	$ 11.03
Options Outstanding Aggregate Intrinsic Value	$ 13,693,937	$ 5,959,720	$ 13,693,937
Options Exercised Aggregate Intrinsic Value	$ 3,805,159
Employee Share Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Volatility Rate	34.76%
Expected Term	1 year 3 months 18 days
Expected Dividend Rate	0.00%
Employee Share Purchase Plan [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk Free Interest Rate	0.40%
Employee Share Purchase Plan [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk Free Interest Rate	0.80%

Shareholders' Equity and Share-based Compensation - Stock Options Outstanding and Exercisable (Details) - $ / shares	3 Months Ended
	Sep. 30, 2016	Jun. 30, 2016
Share-based Compensation [Abstract]
Options, Number Outstanding (in shares)	1,281,024	1,859,260
Options, Weighted-Average Remaining Contractual Life (in years)	5 years	4 years 8 months 16 days
Options, Weighted-Average Exercise Price (in dollars per share)	$ 11.03	$ 11.37
Options, Number Exercisable (in shares)	1,059,449
Options, Weighted-Average Exercise Price (in dollars per share)	$ 11.75
Options vested and expected to vest, Number Outstanding (in shares)	1,266,146
Options vested and expected to vest, Weighted Average Remaining Contractual Life (in years)	4 years 11 months 19 days
Options vested and expected to vest, Weighted Average Exercise Price (in dollars per share)	$ 11.07

Shareholders' Equity and Share-based Compensation - Restricted Stock Activity (Details) - USD ($)	3 Months Ended
	Sep. 30, 2016	Jun. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Weighted Average Remaining Recognition Period (Years)	1 year 5 months 16 days
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Nonvested at June 30, 2016	933,063
Granted	54,376
Vested	(30,973)
Forfeited	(12,575)
Nonvested at September 30, 2016	943,891	933,063
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Nonvested at June 30, 2016	$ 9.18
Granted	19.33
Vested	9.49
Forfeited	11.9
Nonvested at September 30, 2016	$ 9.72	$ 9.18
Weighted Average Remaining Recognition Period (Years)	1 year 6 months 26 days	1 year 8 months 23 days
RSUs Nonvested Aggregate Intrinsic Value	$ 20,501,313	$ 12,997,568
RSUs vested and expected to vest, Outstanding (in shares)	814,711
RSUs vested and expected to vest, Weighted Average Remaining Recognition Period (in years)	1 year 5 months 16 days
RSUs vested and expected to vest, Aggregate Intrinsic Value	$ 17,695,533

Shareholders' Equity and Share-based Compensation - Share-based Compensation Expenses (Details) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	$ 1,316	$ 789
Unrecognized compensation expense	$ 5,400
Recognition period of share-based compensation expense (in years)	1 year 5 months 16 days
Cost of goods sold
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	$ 195	131
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	360	193
Selling, general and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation expense	$ 761	$ 465

Income Taxes - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
Income Taxes - Narrative (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Sep. 30, 2015	Jun. 30, 2016
Related Party Transaction [Line Items]
Income tax expense	$ 1,237	$ 1,214
Estimated effective income tax rate	33.70%	(159.50%)
Increase in prepaid taxes	$ 6,600
Prepaid taxes, current and noncurrent	6,400
Prepaid taxes, current	1,100
Prepaid taxes, noncurrent	5,308		$ 0
Unrecognized tax benefits	6,800
Unrecognized tax benefit that would impact effective tax rate	$ 4,400

Segment and Geographic Information - Revenue by Location and Product Type (Details) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 97,362	$ 81,439
Power discrete
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	71,428	59,912
Power IC
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	22,998	17,514
Packaging and testing services
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	2,936	4,013
Hong Kong
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	82,835	70,453
China
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	12,442	9,016
South Korea
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	366	658
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	894	717
Other Countries
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 825	$ 595

Segment and Geographic Information - Long-lived Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Jun. 30, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment, net	$ 123,048	$ 116,084
China
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment, net	69,567	64,272
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment, net	52,859	51,214
Other Countries
Revenues from External Customers and Long-Lived Assets [Line Items]
Property, plant and equipment, net	$ 622	$ 598

Segment and Geographic Information - Narratives (Details)	3 Months Ended
	Sep. 30, 2016 Segment
Segment Reporting [Abstract]
Number of operating segments	1
Number of reportable segments	1

Commitments and Contingencies - Purchase Commitments (Details) - USD ($) $ in Millions	Sep. 30, 2016	Jun. 30, 2016
Raw materials, wafers, and packaging and testing services puchase commitments
Purchase Commitment, Excluding Long-term Committment [Line Items]
Purchase commitment, amount	$ 38.6	$ 39.6
Property and equipment purchase commitments
Purchase Commitment, Excluding Long-term Committment [Line Items]
Purchase commitment, amount	$ 6.2	$ 6.6

Commitments and Contingencies - Guarantees (Details) - USD ($)	Sep. 30, 2016	Jun. 30, 2016
Indemnification Agreement
Loss Contingencies [Line Items]
Indemnifications accrual	$ 0	$ 0

Commitments and Contingencies - Other Investments (Details) - Facility in Liangjiang New Area of Chongqing (the 'Joint Venture') [Member] - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Mar. 31, 2016	Jun. 30, 2017	Mar. 29, 2016
Corporate Joint Venture [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Initial capitalization of joint venture			$ 330.0
Parent Company [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Subsidiary or Equity Method Investee, Cumulative Percentage Ownership after All Transactions	51.00%
Chongqing Funds [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Subsidiary or Equity Method Investee, Cumulative Percentage Ownership after All Transactions	49.00%
Scenario, Forecast [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Consideration transferred to acquire interest in joint venture		$ 10.0