Alpha and Omega Semiconductor Limited (AOSL) 10-Q 7 Feb 14 2014 Q2 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	6 Months Ended
	Dec. 31, 2013	Jan. 31, 2014
Entity Information [Line Items]	'	'
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	31-Dec-13	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q2	'
Amendment Flag	'false	'
Entity Common Stock, Shares Outstanding	'	25,994,027

CONDENSED_CONSOLIDATED_BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (USD $)	Dec. 31, 2013	Jun. 30, 2013
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$102,533	$92,406
Restricted cash	206	204
Accounts receivable, net	39,002	38,298
Inventories	62,767	68,339
Deferred income tax assets	2,191	3,030
Other current assets	3,376	3,578
Total current assets	210,075	205,855
Property, plant and equipment, net	127,508	138,111
Intangible assets, net	296	496
Goodwill	269	269
Deferred income tax assets	10,766	10,823
Other long-term assets	1,261	767
Total assets	350,175	356,321
Current liabilities:	'	'
Short term debt	3,107	3,821
Accounts payable	25,779	31,738
Accrued liabilities	15,372	14,571
Income taxes payable	1,506	1,472
Deferred margin	611	622
Capital leases	695	1,267
Total current liabilities	47,070	53,491
Long-term debt	12,143	13,571
Income taxes payable - long term	3,371	3,692
Deferred income tax liabilities	2,214	2,613
Capital leases - long term	100	195
Deferred rent	1,227	1,308
Total liabilities	66,125	74,870
Commitments and contingencies (Note 9)	'	'
Preferred shares, par value $0.002 per share:	'	'
Authorized: 10,000 shares: Issued and outstanding: none at December 31, 2013 and June 30, 2013	0	0
Common shares, par value $0.002 per share:	'	'
Authorized: 50,000 shares: Issued and outstanding: 26,178 shares and 25,955 shares at December 31, 2013 and 25,882 shares and 25,656 shares at June 30, 2013	52	51
Treasury shares at cost: 223 shares at December 31, 2013 and 226 shares at June 30, 2013	-2,013	-2,054
Additional paid-in capital	170,434	168,352
Accumulated other comprehensive income	1,006	957
Retained earnings	114,571	114,145
Total shareholders’ equity	284,050	281,451
Total liabilities and shareholders’ equity	$350,175	$356,321

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Dec. 31, 2013	Jun. 30, 2013
Common shares, par value (in dollars per share)	$0.00	$0.00
Common shares, authorized (in shares)	50,000,000	50,000,000
Common stock, shares issued (in shares)	26,178,000	25,882,000
Common stock, shares outstanding (in shares)	25,955,000	25,656,000
Preferred stock, par value (in dollars per share)	$0.00	$0.00
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)	223,000	226,000

CONDENSED_CONSOLIDATED_STATEME

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (USD $)	3 Months Ended		6 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
Revenue	$76,265	$89,448	$160,386	$185,209
Cost of goods sold	62,646	68,854	129,616	139,082
Gross profit	13,619	20,594	30,770	46,127
Operating expenses	'	'	'	'
Research and development	4,972	6,866	11,819	13,799
Selling, general and administrative	7,309	8,838	16,249	17,619
Total operating expenses	12,281	15,704	28,068	31,418
Operating income	1,338	4,890	2,702	14,709
Interest income	14	20	38	37
Interest expense	-69	-107	-148	-189
Income before income taxes	1,283	4,803	2,592	14,557
Income tax expense	1,123	1,085	2,125	2,897
Net income	$160	$3,718	$467	$11,660
Net income per share	'	'	'	'
Basic (in dollars per share)	$0.01	$0.15	$0.02	$0.46
Diluted (in dollars per share)	$0.01	$0.14	$0.02	$0.45
Weighted average number of common shares used to compute net income per share	'	'	'	'
Basic (in shares)	25,846	25,292	25,765	25,165
Diluted (in shares)	26,462	26,101	26,385	25,992

CONDENSED_CONSOLIDATED_STATEME1

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
Net income	$160	$3,718	$467	$11,660
Other comprehensive income, net of tax	'	'	'	'
Foreign currency translation adjustment	-5	25	49	55
Total comprehensive income	$155	$3,743	$516	$11,715

CONDENSED_CONSOLIDATED_STATEME2

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	6 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities	'	'
Net income	$467	$11,660
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Depreciation	13,748	14,498
Amortization	200	286
Share-based compensation expense	1,314	2,354
Deferred income taxes, net	497	624
(Gain) loss on disposal of property and equipment	-120	51
Changes in working capital:	'	'
Accounts receivable	-704	-4,117
Inventories	5,572	-5,710
Other current and long-term assets	-292	1,850
Accounts payable	-5,961	2,496
Income taxes payable	-287	218
Accrued and other liabilities	607	-1,542
Net cash provided by operating activities	15,041	22,668
Cash flows from investing activities	'	'
Purchases of property and equipment	-3,282	-12,531
Proceeds from sale of property and equipment	244	0
Restricted cash placed	-2	-125
Net cash used in investing activities	-3,040	-12,656
Cash flows from financing activities	'	'
Proceeds from exercise of stock options and ESPP	930	2,051
Payment for repurchase of common shares	0	-5
Proceeds from borrowings	0	250
Repayments of borrowings	-2,143	-2,143
Principal payments on capital leases	-667	-479
Net cash used in financing activities	-1,880	-326
Effect of exchange rate changes on cash and cash equivalents	6	12
Net increase in cash and cash equivalents	10,127	9,698
Cash and cash equivalents at beginning of period	92,406	82,166
Cash and cash equivalents at end of period	102,533	91,864
Supplemental disclosures of non-cash investing information:	'	'
Property and equipment purchased but not yet paid	$1,808	$3,144

The_Company_and_Significant_Ac

The Company and Significant Accounting Policies	6 Months Ended
	Dec. 31, 2013
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 portable 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, Macau, China, Taiwan, Korea and Japan.
	Basis of Preparation
	The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”) for interim financial information and with the instructions to Article 10 of Securities and Exchange Commission Regulation S-X, 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, 2013. All significant intercompany balances and transactions have been eliminated in consolidation. In the opinion of management, all adjustments (consisting of normal recurring adjustments and accruals) considered necessary for a fair presentation of the results of operations for the period presented have been included in the interim periods. Operating results for the three and six months ended December 31, 2013 are not necessarily indicative of the results that may be expected for other interim periods or the fiscal year ending June 30, 2014. The condensed consolidated balance sheet at June 30, 2013 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, 2013.
	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, variable interest entities, 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. The carrying value of the Company's debt is considered a reasonable estimate of fair value which is estimated by considering the current rates available to the Company for debt of the same remaining maturities, structure and terms of the debts.
	Comprehensive Income
	Comprehensive income 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 consists of cumulative foreign currency translation adjustments. Total comprehensive income is presented in the condensed consolidated statements of comprehensive income.
	Recent Accounting Pronouncements
	In July 2013, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update ("ASU") 2013-11, Income Taxes (Topic 740) Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists. The new guidance requires the netting of unrecognized tax benefits ("UTBs") against a deferred tax asset for a loss or other carryforward that would apply in settlement of the uncertain tax positions. Under the new standard, UTBs will be netted against all available same-jurisdiction loss or other tax carryforwards that would be utilized, rather than only against carryforwards that are created by the UTBs. The ASU is effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. Early adoption is permitted. The ASU should be applied prospectively to all unrecognized tax benefits that exist at the effective date. Retrospective application is permitted. The Company does not expect the adoption of this guidance to have any significant impact on the Company's condensed consolidated financial statements.

Net_Income_Per_Share

Net Income Per Share	6 Months Ended
	Dec. 31, 2013
Earnings Per Share [Abstract]	'
Net Income Per Share	'
	Net Income Per Share
	The following table presents the calculation of basic and diluted net income per share:
		Three Months Ended December 31,						Six Months Ended December 31,
		2013			2012			2013		2012
		(in thousands, except per share data)
	Numerator:
	Net income	$	160		$	3,718		$	467	$	11,660
	Denominator:
	Basic:
	Weighted average number of common shares used to compute basic net income per share	25,846			25,292			25,765		25,165
	Diluted:
	Weighted average number of common shares used to compute basic net income per share	25,846			25,292			25,765		25,165
	Effect of potentially dilutive securities:
	Stock options, RSUs and ESPP shares	616			809			620		827
	Weighted average number of common shares used to compute diluted net income per share	26,462			26,101			26,385		25,992
	Net income per share:
	Basic	$	0.01		$	0.15		$	0.02	$	0.46
	Diluted	$	0.01		$	0.14		$	0.02	$	0.45
	The following potential dilutive securities were excluded from the computation of diluted net income per share as their effect would have been anti-dilutive:
		Three Months Ended December 31,					Six Months Ended December 31,
		2013		2012			2013		2012
		(in thousands)
	Employee stock options and RSUs	2,700		2,841			2,742		2,768
	ESPP to purchase common shares	302		187			304		251
	Total potential dilutive securities	3,002		3,028			3,046		3,019

Concentration_of_Credit_Risk_a

Concentration of Credit Risk and Significant Customers	6 Months Ended
	Dec. 31, 2013
Risks and Uncertainties [Abstract]	'
Concentration of Credit Risk and Significant Customers	'
	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 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 financial assets 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 bad debt 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 10% or higher than the respective total consolidated amounts:
		Three Months Ended December 31,				Six Months Ended December 31,
	Percentage of revenue	2013		2012		2013		2012
	Customer A	22.7	%	24.2	%	21.6	%	23.9	%
	Customer B	42.2	%	43.8	%	43.3	%	42.6	%
	Customer C	13	%	11.2	%	12.4	%	12.5	%
		December 31,		June 30,
	Percentage of accounts receivable	2013		2013
	Customer A	20.4	%	33.8	%
	Customer B	35.9	%	22.6	%
	Customer C	17	%	19.9	%

Balance_Sheet_Components

Balance Sheet Components	6 Months Ended
	Dec. 31, 2013
Balance Sheet Related Disclosures [Abstract]	'
Balance Sheet Components	'
	Balance Sheet Components
	Accounts receivable:
		December 31,			June 30,
		2013			2013
		(in thousands)
	Accounts receivable	$	54,099		$	52,202
	Less: Allowance for price adjustments	(15,067		)	(13,152		)
	Less: Allowance for doubtful accounts	(30		)	(752		)
	Accounts receivable, net	$	39,002		$	38,298
	Inventories:
		December 31,			June 30,
		2013			2013
		(in thousands)
	Raw materials	$	17,445		$	17,248
	Work in-process	36,165			38,618
	Finished goods	9,157			12,473
		$	62,767		$	68,339
	Property, plant and equipment:
		December 31,			June 30,
		2013			2013
		(in thousands)
	Land	$	4,950		$	4,950
	Building	4,106			4,106
	Manufacturing machinery and equipment	159,338			156,958
	Equipment and tooling	10,413			10,356
	Computer equipment and software	16,835			16,140
	Office furniture and equipment	1,564			1,559
	Leasehold improvements	24,434			24,068
		221,640			218,137
	Less accumulated depreciation	(100,932		)	(87,180		)
		120,708			130,957
	Equipment and construction in progress	6,800			7,154
	Property, plant and equipment, net	$	127,508		$	138,111
	Other long term assets:
		December 31,			June 30,
		2013			2013
		(in thousands)
	Prepayments for property and equipment	$	707		$	77
	Investment in a privately held company	100			100
	Deferred debt issuance cost	43			91
	Office leases deposits	411			499
		$	1,261		$	767
	Accrued liabilities:
		December 31,			June 30,
		2013			2013
		(in thousands)
	Accrued salaries and wages	$	4,216		$	3,079
	Accrued vacation	968			2,078
	Accrued bonuses	1,153			880
	Warranty accrual	1,496			1,428
	Stock rotation accrual	1,480			1,572
	Accrued professional fees	607			918
	ESPP payable	290			353
	Customer deposits	488			123
	Other accrued expenses	4,674			4,140
		$	15,372		$	14,571
	The activities in the warranty accrual, included in accrued liabilities, are as follows:
		Six Months Ended December 31,
		2013			2012
		(in thousands)
	Beginning balance	$	1,428		$	1,556
	Additions	1,239			733
	Utilization	(1,171		)	(616		)
Ending balance	$	1,496		$	1,673
The activities in the stock rotation accrual, included in accrued liabilities, are as follows:
	Six Months Ended December 31,
	2013			2012
	(in thousands)
Beginning balance	$	1,572		$	2,032
Additions	2,332			3,254
Utilization	(2,424		)	(3,519		)
Ending balance	$	1,480		$	1,767

Debt

Debt	6 Months Ended
	Dec. 31, 2013
Debt Disclosure [Abstract]	'
Debt	'
	Debt
	On May 11, 2012, the Company entered into a loan agreement with a financial institution that provides a term loan of $20.0 million for general purposes and a $10.0 million non-revolving credit line for the purchase of equipment. Both the term loan and equipment line will be fully repayable in May 2015. The borrowings may be made in the form of either Eurodollar loans or Base Rate loans. Eurodollar loans accrue interest based on an adjusted London Interbank Offered Rate ("LIBOR") as defined in the agreement, plus a margin of 1.00% to 1.75%. Base Rate loans accrue interest at the highest of (a) the lender's Prime Rate, (b) the Federal Funds Rate plus 0.5% and (c) the Eurodollar Rate (for a one-month interest period) plus 1%; plus a margin of -0.5% to 0.25%. The applicable margins for both Eurodollar loans and Base Rate loans will vary from time to time in the foregoing ranges based on the cash and cash equivalent balances maintained by the Company and its subsidiaries with the lender. In May 2013, the equipment credit line expired and there was no outstanding balance. As of December 31, 2013 and June 30, 2013, the outstanding balances of the term loan were $15.0 million and $17.1 million, respectively. Of the $15.0 million and $17.1 million term loan, $2.9 million and $3.6 million were included as short-term debt as of December 31, 2013 and June 30, 2013, respectively.
	The obligations under the term loan are secured by substantially all assets of two subsidiaries of the Company, including, but not limited to, certain real property and related assets located at the Oregon fab. In addition, the Company and certain subsidiaries of the Company have agreed to guarantee full repayment and performance of the obligations under the loan agreement. The loan agreement contains customary restrictive covenants and includes certain financial covenants that require the Company to maintain on a consolidated basis specified financial ratios including total liabilities to tangible net worth, fixed charge coverage and current assets to current liabilities. As of December 31, 2013, the Company was in compliance with these covenants.
	Two of the Company's subsidiaries in China had revolving lines of credit that allow each of the subsidiaries to draw down, from time to time, up to 80% of the accounts receivable balance of such subsidiary, with an aggregated maximum amount of RMB 95 million (equivalent of $15.7 million based on the currency exchange rate as of December 31, 2013) to finance the subsidiary's working capital with a maximum of 120-day repayment term. The interest rate on each draw down varies and is indexed to the published LIBOR. The lines expired in September 2013 and the Company is currently in the process of renewing them. As of December 31, 2013, there was no outstanding balance under these two revolving lines of credit.
	During July 2012, the Company entered into a loan agreement with the State of Oregon for an amount of $250,000. The loan is required to be used for training new and re-training existing employees of the Oregon Fab. The loan bears a compound annual interest rate of 5.0% and is to be repaid in April 2014. The State may forgive the loan and unpaid interest if certain conditions primarily relating to hiring targets are met and it is more likely than not that the Company will meet those hiring targets. As of December 31, 2013 and June 30, 2013, the outstanding balance and accrued interest of the loan, included in short term debt, was $269,000 and $262,000, respectively.

Shareholders_Equity_and_Shareb

Shareholders' Equity and Share-based Compensation	6 Months Ended
	Dec. 31, 2013
Share-based Compensation [Abstract]	'
Shareholders' Equity and Share-based Compensation	'
	Shareholders' Equity and Share-based Compensation
	Share Repurchase
	On October 22, 2010, the Company's board of directors authorized a $25.0 million share repurchase program. Under this repurchase program the Company may, from time to time, repurchase shares from the open market or in privately negotiated transactions, subject to supervision and oversight by the board. The Company accounts for treasury stock under the cost method. Shares repurchased are accounted for as treasury shares and the total cost of shares repurchased is recorded as a reduction of shareholders' equity. From time to time, treasury shares may be reissued as part of the Company's stock-based compensation programs. Gains on re-issuance of treasury stock are credited to additional paid-in capital; losses are charged to additional paid-in capital to offset the net gains, if any, from previous sales or re-issuance of treasury stock. Any remaining balance of the losses are charged to retained earnings.
	During the three and six months ended December 31, 2013, the Company did not repurchased any shares under the program. During the three and six months ended December 31, 2013, the Company reissued 2,700 and 2,950 shares, respectively, with weighted average repurchase cost of $13.82 per share for both periods, upon vesting of certain restricted stock units ("RSU").
	As of December 31, 2013, the Company repurchased an aggregate of 241,770 shares for a total cost of $2.3 million, at an average repurchase price of $9.40 per share since inception of the program. Of the 241,770 repurchased shares, 18,750 shares with a weighted average repurchase price of $13.81 per share were reissued at an average price of $3.47 per share for option exercises and vested RSUs.
	Stock Options
	The following table summarizes the Company's stock option activities for the six months ended December 31, 2013:
					Weighted
					Average
		Number of			Exercise Price				Aggregate
		Shares			Per Share				Intrinsic Value
	Outstanding at June 30, 2013	3,593,854			$	10.24			$	3,144,506
	Granted	77,500			7.51
	Exercised	(119,321	)		0.98				772,342
	Canceled or forfeited	(237,461	)		11.18
	Outstanding at December 31, 2013	3,314,572			$	10.45			$	2,409,612
	Information with respect to stock options outstanding and exercisable at December 31, 2013 is as follows:
		Options Outstanding									Options Vested and Exercisable
		Number Outstanding			Weighted-Average		Weighted-Average				Number Exercisable		Weighted-Average
					Remaining Contractual Life (years)		Exercise Price						Exercise Price
	Total options outstanding	3,314,572			4.43		$	10.45			2,778,724		$	10.29
	Options vested and expected to vest	3,280,477			4.36		$	10.44
	Options expected to vest are the result of applying the pre-vesting forfeiture rate assumption to total outstanding options.
	The fair value of stock options granted were estimated at the date of grant using the Black-Scholes option valuation model for the six months ended December 31, 2013 with the following weighted average assumptions:
		Six Months Ended December 31,
		2013
	Volatility rate	48%
	Risk-free interest rate	1.6% - 1.7%
	Expected term	5.5 years
	Dividend yield	0%
	Restricted Stock Units ("RSU")
	The following table summarizes the Company's RSU activities for the six months ended December 31, 2013:
		Number of Restricted Stock			Weighted Average				Weighted Average		Aggregate Intrinsic Value
		Units			Grant Date Fair				Remaining
					Value Per Share				Recognition
									Period (Years)
	Nonvested at June 30, 2013	549,553			$	9.5			1.87		$	4,198,585
	Granted	55,804			7.65
	Vested	(71,960	)		9.65
	Forfeited	(73,952	)		9.72
	Nonvested at December 31, 2013	459,445			$	9.22			1.67		$	3,542,321
	RSUs vested and expected to vest	415,616							1.6		$	3,204,396
	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
	The Employee Share Purchase Plan (the "ESPP") was established in May 2010 upon the completion of the Company's initial public offering. The assumptions used to estimate the fair values of common shares issued under the ESPP were as follows:
		Six Months Ended December 31,
		2013
	Volatility rate	50%
	Risk-free interest rate	0.1% - 0.3%
	Expected term	1.3 years
	Dividend yield	0%
	Share-based Compensation Expense
	The total share-based compensation expense (reversal) related to stock options, ESPP and RSUs described above, recognized in the condensed consolidated statements of operations for the periods presented was as follows:
		Three Months Ended December 31,								Six Months Ended December 31,
		2013				2012				2013			2012
		(in thousands)								(in thousands)
	Cost of goods sold	$	142			$	141			$	338		$	339
	Research and development	(32		)		278				263			671
	Selling, general and administrative	(5		)		494				713			1,344
		$	105			$	913			$	1,314		$	2,354
	Total unrecognized stock-based compensation expense as of December 31, 2013 was $3.8 million, which includes estimated forfeitures and is expected to be recognized over a weighted-average period of 1.3 years.

Income_Taxes

Income Taxes	6 Months Ended
	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	Income Taxes
	The Company recognized income tax expense of approximately $1.1 million for both the three months ended December 31, 2013 and 2012. The Company recognized income tax expense of approximately $2.1 million and $2.9 million for the six months ended December 31, 2013 and 2012, respectively. The estimated effective tax rate was 87.5% and 22.6% for the three months ended December 31, 2013 and 2012, respectively. The estimated effective tax rate was 82.0% and 19.9% for the six months ended December 31, 2013 and 2012, respectively. The effective tax rate for the three and the six months ended December 31, 2013 was higher than that for same period of last year primarily due to the changes in the mix of earnings in various geographic jurisdictions between the two periods.
	The Company files its income tax returns in the United States and in various foreign jurisdictions. The tax years 2001 to 2013 remain open to examination by U.S. federal and state tax authorities. The tax years 2005 to 2013 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 December 31, 2013, the gross amount of unrecognized tax benefits was approximately $7.6 million. 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.

Segment_and_Geographic_Informa

Segment and Geographic Information	6 Months Ended
	Dec. 31, 2013
Segment Reporting [Abstract]	'
Segment and Geographic Information	'
	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 December 31,				Six Months Ended December 31,
		2013		2012		2013		2012
		(in thousands)				(in thousands)
	Hong Kong	$	64,229	$	71,251	$	135,485	$	145,878
	China	10,156		15,336		21,048		32,965
	South Korea	745		1,392		1,542		3,660
	United States	425		313		898		656
	Other countries	710		1,156		1,413		2,050
		$	76,265	$	89,448	$	160,386	$	185,209
	The following is a summary of revenue by product type:
		Three Months Ended December 31,				Six Months Ended December 31,
		2013		2012		2013		2012
		(in thousands)				(in thousands)
	Power discrete	$	58,946	$	70,801	$	124,091	$	146,305
	Power IC	13,226		12,936		26,838		27,467
	Packaging and testing services	4,093		5,711		9,457		11,437
		$	76,265	$	89,448	$	160,386	$	185,209
	Long-lived assets, consisting of property, plant and equipment by geographical area are as follows:
		December 31,		June 30,
		2013		2013
		(in thousands)
	China	$	85,704	$	93,663
	United States	41,389		43,946
	Other countries	415		502
		$	127,508	$	138,111

Commitments_and_Contingencies

Commitments and Contingencies	6 Months Ended
	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	Commitments and Contingencies
	Purchase Commitments
	As of December 31, 2013 and June 30, 2013, the Company had approximately $30.0 million and $25.8 million, respectively, of outstanding purchase commitments primarily for purchases of semiconductor raw materials, wafers, spare parts and packaging and testing services; and approximately $4.2 million and $0.4 million, respectively, of capital commitments for the purchase of property and equipment.
	Contingencies and Indemnities
	The Company is currently not a party to any 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 thereof or could 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 December 31, 2013 and June 30, 2013.
	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.

The_Company_and_Significant_Ac1

The Company and Significant Accounting Policies (Policies)	6 Months Ended
	Dec. 31, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Nature of Operations [Text Block]	'
	The Company
	Alpha and Omega Semiconductor Limited and its subsidiaries (the “Company,” "AOS," "we" or "us") design, develop and supply a broad range of power semiconductors. The Company's portfolio of products targets high-volume applications, including portable computers, flat panel TVs, 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, Macau, China, Taiwan, Korea and Japan.
Concentration Risk, Credit Risk, Policy [Policy Text Block]	'
	The Company manages its credit risk associated with exposure to distributors and direct customers on outstanding accounts receivable through the application 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 financial assets 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 bad debt 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.
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, 2013. All significant intercompany balances and transactions have been eliminated in consolidation. In the opinion of management, all adjustments (consisting of normal recurring adjustments and accruals) considered necessary for a fair presentation of the results of operations for the period presented have been included in the interim periods. Operating results for the three and six months ended December 31, 2013 are not necessarily indicative of the results that may be expected for other interim periods or the fiscal year ending June 30, 2014. The condensed consolidated balance sheet at June 30, 2013 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, 2013.
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, variable interest entities, 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. The carrying value of the Company's debt is considered a reasonable estimate of fair value which is estimated by considering the current rates available to the Company for debt of the same remaining maturities, structure and terms of the debts.
Comprehensive Income (Loss)	'
	Comprehensive Income
	Comprehensive income 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 consists of cumulative foreign currency translation adjustments. Total comprehensive income is presented in the condensed consolidated statements of comprehensive income.
Recent Accounting Pronouncements	'
	Recent Accounting Pronouncements
	In July 2013, the Financial Accounting Standards Board (the “FASB”) issued Accounting Standards Update ("ASU") 2013-11, Income Taxes (Topic 740) Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists. The new guidance requires the netting of unrecognized tax benefits ("UTBs") against a deferred tax asset for a loss or other carryforward that would apply in settlement of the uncertain tax positions. Under the new standard, UTBs will be netted against all available same-jurisdiction loss or other tax carryforwards that would be utilized, rather than only against carryforwards that are created by the UTBs. The ASU is effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. Early adoption is permitted. The ASU should be applied prospectively to all unrecognized tax benefits that exist at the effective date. Retrospective application is permitted. The Company does not expect the adoption of this guidance to have any significant impact on the Company's condensed consolidated financial statements.

Net_Income_Per_Share_Tables

Net Income Per Share (Tables)	6 Months Ended
	Dec. 31, 2013
Earnings Per Share [Abstract]	'
Schedule of Earnings Per Share, Basic and Diluted	'
	The following table presents the calculation of basic and diluted net income per share:
		Three Months Ended December 31,						Six Months Ended December 31,
		2013			2012			2013		2012
		(in thousands, except per share data)
	Numerator:
	Net income	$	160		$	3,718		$	467	$	11,660
	Denominator:
	Basic:
	Weighted average number of common shares used to compute basic net income per share	25,846			25,292			25,765		25,165
	Diluted:
	Weighted average number of common shares used to compute basic net income per share	25,846			25,292			25,765		25,165
	Effect of potentially dilutive securities:
	Stock options, RSUs and ESPP shares	616			809			620		827
	Weighted average number of common shares used to compute diluted net income per share	26,462			26,101			26,385		25,992
	Net income per share:
	Basic	$	0.01		$	0.15		$	0.02	$	0.46
	Diluted	$	0.01		$	0.14		$	0.02	$	0.45
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 per share as their effect would have been anti-dilutive:
		Three Months Ended December 31,					Six Months Ended December 31,
		2013		2012			2013		2012
		(in thousands)
	Employee stock options and RSUs	2,700		2,841			2,742		2,768
	ESPP to purchase common shares	302		187			304		251
	Total potential dilutive securities	3,002		3,028			3,046		3,019

Concentration_of_Credit_Risk_a1

Concentration of Credit Risk and Significant Customers (Tables)	6 Months Ended
	Dec. 31, 2013
Risks and Uncertainties [Abstract]	'
Schedules of Concentration of Risk, by Risk Factor	'
	Summarized below are individual customers whose revenue or accounts receivable balances were 10% or higher than the respective total consolidated amounts:
		Three Months Ended December 31,				Six Months Ended December 31,
	Percentage of revenue	2013		2012		2013		2012
	Customer A	22.7	%	24.2	%	21.6	%	23.9	%
	Customer B	42.2	%	43.8	%	43.3	%	42.6	%
	Customer C	13	%	11.2	%	12.4	%	12.5	%
		December 31,		June 30,
	Percentage of accounts receivable	2013		2013
	Customer A	20.4	%	33.8	%
	Customer B	35.9	%	22.6	%
	Customer C	17	%	19.9	%

Balance_Sheet_Components_Table

Balance Sheet Components (Tables)	6 Months Ended
	Dec. 31, 2013
Balance Sheet Related Disclosures [Abstract]	'
Schedule of Accounts, Notes, Loans and Financing Receivable	'
	Accounts receivable:
		December 31,			June 30,
		2013			2013
		(in thousands)
	Accounts receivable	$	54,099		$	52,202
	Less: Allowance for price adjustments	(15,067		)	(13,152		)
	Less: Allowance for doubtful accounts	(30		)	(752		)
	Accounts receivable, net	$	39,002		$	38,298
Schedule of Inventory, Current	'
	Inventories:
		December 31,			June 30,
		2013			2013
		(in thousands)
	Raw materials	$	17,445		$	17,248
	Work in-process	36,165			38,618
	Finished goods	9,157			12,473
		$	62,767		$	68,339
Property, Plant and Equipment	'
	Property, plant and equipment:
		December 31,			June 30,
		2013			2013
		(in thousands)
	Land	$	4,950		$	4,950
	Building	4,106			4,106
	Manufacturing machinery and equipment	159,338			156,958
	Equipment and tooling	10,413			10,356
	Computer equipment and software	16,835			16,140
	Office furniture and equipment	1,564			1,559
	Leasehold improvements	24,434			24,068
		221,640			218,137
	Less accumulated depreciation	(100,932		)	(87,180		)
		120,708			130,957
	Equipment and construction in progress	6,800			7,154
	Property, plant and equipment, net	$	127,508		$	138,111
Schedule of Other Assets, Noncurrent	'
	Other long term assets:
		December 31,			June 30,
		2013			2013
		(in thousands)
	Prepayments for property and equipment	$	707		$	77
	Investment in a privately held company	100			100
	Deferred debt issuance cost	43			91
	Office leases deposits	411			499
		$	1,261		$	767
Schedule of Accrued Liabilities	'
	Accrued liabilities:
		December 31,			June 30,
		2013			2013
		(in thousands)
	Accrued salaries and wages	$	4,216		$	3,079
	Accrued vacation	968			2,078
	Accrued bonuses	1,153			880
	Warranty accrual	1,496			1,428
	Stock rotation accrual	1,480			1,572
	Accrued professional fees	607			918
	ESPP payable	290			353
	Customer deposits	488			123
	Other accrued expenses	4,674			4,140
		$	15,372		$	14,571
Schedule of Product Warranty Liability	'
	The activities in the warranty accrual, included in accrued liabilities, are as follows:
		Six Months Ended December 31,
		2013			2012
		(in thousands)
	Beginning balance	$	1,428		$	1,556
	Additions	1,239			733
	Utilization	(1,171		)	(616		)
	Ending balance	$	1,496		$	1,673
Stock Rotation Accrual	'
	The activities in the stock rotation accrual, included in accrued liabilities, are as follows:
		Six Months Ended December 31,
		2013			2012
		(in thousands)
	Beginning balance	$	1,572		$	2,032
	Additions	2,332			3,254
	Utilization	(2,424		)	(3,519		)
	Ending balance	$	1,480		$	1,767

Shareholders_Equity_and_Shareb1

Shareholders' Equity and Share-based Compensation (Tables)	6 Months Ended
	Dec. 31, 2013
Share-based Compensation [Abstract]	'
Summary of Stock Option Activites	'
	Stock Options
	The following table summarizes the Company's stock option activities for the six months ended December 31, 2013:
					Weighted
					Average
		Number of			Exercise Price				Aggregate
		Shares			Per Share				Intrinsic Value
	Outstanding at June 30, 2013	3,593,854			$	10.24			$	3,144,506
	Granted	77,500			7.51
	Exercised	(119,321	)		0.98				772,342
	Canceled or forfeited	(237,461	)		11.18
	Outstanding at December 31, 2013	3,314,572			$	10.45			$	2,409,612
	Information with respect to stock options outstanding and exercisable at December 31, 2013 is as follows:
		Options Outstanding									Options Vested and Exercisable
		Number Outstanding			Weighted-Average		Weighted-Average				Number Exercisable		Weighted-Average
					Remaining Contractual Life (years)		Exercise Price						Exercise Price
	Total options outstanding	3,314,572			4.43		$	10.45			2,778,724		$	10.29
	Options vested and expected to vest	3,280,477			4.36		$	10.44
	Options expected to vest are the result of applying the pre-vesting forfeiture rate assumption to total outstanding options.
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	'
	The fair value of stock options granted were estimated at the date of grant using the Black-Scholes option valuation model for the six months ended December 31, 2013 with the following weighted average assumptions:
		Six Months Ended December 31,
		2013
	Volatility rate	48%
	Risk-free interest rate	1.6% - 1.7%
	Expected term	5.5 years
	Dividend yield	0%
Restricted Stock Units Activity	'
	Restricted Stock Units ("RSU")
	The following table summarizes the Company's RSU activities for the six months ended December 31, 2013:
		Number of Restricted Stock			Weighted Average				Weighted Average		Aggregate Intrinsic Value
		Units			Grant Date Fair				Remaining
					Value Per Share				Recognition
									Period (Years)
	Nonvested at June 30, 2013	549,553			$	9.5			1.87		$	4,198,585
	Granted	55,804			7.65
	Vested	(71,960	)		9.65
	Forfeited	(73,952	)		9.72
	Nonvested at December 31, 2013	459,445			$	9.22			1.67		$	3,542,321
	RSUs vested and expected to vest	415,616							1.6		$	3,204,396
	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
	The Employee Share Purchase Plan (the "ESPP") was established in May 2010 upon the completion of the Company's initial public offering. The assumptions used to estimate the fair values of common shares issued under the ESPP were as follows:
		Six Months Ended December 31,
		2013
	Volatility rate	50%
	Risk-free interest rate	0.1% - 0.3%
	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 (reversal) related to stock options, ESPP and RSUs described above, recognized in the condensed consolidated statements of operations for the periods presented was as follows:
		Three Months Ended December 31,								Six Months Ended December 31,
		2013				2012				2013			2012
		(in thousands)								(in thousands)
	Cost of goods sold	$	142			$	141			$	338		$	339
	Research and development	(32		)		278				263			671
	Selling, general and administrative	(5		)		494				713			1,344
		$	105			$	913			$	1,314		$	2,354

Segment_and_Geographic_Informa1

Segment and Geographic Information (Tables)	6 Months Ended
	Dec. 31, 2013
Segment Reporting [Abstract]	'
Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas	'
	Long-lived assets, consisting of property, plant and equipment by geographical area are as follows:
		December 31,		June 30,
		2013		2013
		(in thousands)
	China	$	85,704	$	93,663
	United States	41,389		43,946
	Other countries	415		502
		$	127,508	$	138,111
	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 December 31,				Six Months Ended December 31,
		2013		2012		2013		2012
		(in thousands)				(in thousands)
	Hong Kong	$	64,229	$	71,251	$	135,485	$	145,878
	China	10,156		15,336		21,048		32,965
	South Korea	745		1,392		1,542		3,660
	United States	425		313		898		656
	Other countries	710		1,156		1,413		2,050
		$	76,265	$	89,448	$	160,386	$	185,209
Revenue from External Customers by Products and Services	'
	The following is a summary of revenue by product type:
		Three Months Ended December 31,				Six Months Ended December 31,
		2013		2012		2013		2012
		(in thousands)				(in thousands)
	Power discrete	$	58,946	$	70,801	$	124,091	$	146,305
	Power IC	13,226		12,936		26,838		27,467
	Packaging and testing services	4,093		5,711		9,457		11,437
		$	76,265	$	89,448	$	160,386	$	185,209

Net_Income_Per_Share_Basic_and

Net Income Per Share - Basic and Diluted Income Per Share (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
Numerator:	'	'	'	'
Net income	$160	$3,718	$467	$11,660
Basic:	'	'	'	'
Weighted average number of common shares used to compute basic net income per share	25,846	25,292	25,765	25,165
Effect of potentially dilutive securities:	'	'	'	'
Stock options, RSUs and ESPP shares (in shares)	616	809	620	827
Weighted average number of common shares used to compute diluted net income per share	26,462	26,101	26,385	25,992
Net income per share:	'	'	'	'
Basic (in dollars per share)	$0.01	$0.15	$0.02	$0.46
Diluted (in dollars per share)	$0.01	$0.14	$0.02	$0.45

Net_Income_Per_Share_Potential

Net Income Per Share - Potential Dilutive Shares (Details)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Potential dilutive securities (in shares)	3,002	3,028	3,046	3,019
Employee stock options and RSUs	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Potential dilutive securities (in shares)	2,700	2,841	2,742	2,768
ESPP to purchase common shares	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Potential dilutive securities (in shares)	302	187	304	251

Concentration_of_Credit_Risk_a2

Concentration of Credit Risk and Significant Customers - (Details)

6 Months Ended

3 Months Ended

6 Months Ended

3 Months Ended

6 Months Ended

3 Months Ended

6 Months Ended

3 Months Ended

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Jun. 30, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Jun. 30, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Jun. 30, 2013

Minimum

Maximum

Customer A

Customer A

Customer A

Customer A

Customer A

Customer A

Customer B

Customer B

Customer B

Customer B

Customer B

Customer B

Customer C

Customer C

Customer C

Customer C

Customer C

Customer C

Sales Revenue, Goods, Net

Sales Revenue, Goods, Net

Sales Revenue, Goods, Net

Sales Revenue, Goods, Net

Accounts Receivable

Accounts Receivable

Sales Revenue, Goods, Net

Sales Revenue, Goods, Net

Sales Revenue, Goods, Net

Sales Revenue, Goods, Net

Accounts Receivable

Accounts Receivable

Sales Revenue, Goods, Net

Sales Revenue, Goods, Net

Sales Revenue, Goods, Net

Sales Revenue, Goods, Net

Accounts Receivable

Accounts Receivable

Customer Concentration Risk

Customer Concentration Risk

Customer Concentration Risk

Customer Concentration Risk

Customer Concentration Risk

Customer Concentration Risk

Customer Concentration Risk

Customer Concentration Risk

Customer Concentration Risk

Customer Concentration Risk

Customer Concentration Risk

Customer Concentration Risk

Customer Concentration Risk

Customer Concentration Risk

Customer Concentration Risk

Customer Concentration Risk

Customer Concentration Risk

Customer Concentration Risk

Concentration Risk

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Terms of credit sales, (in days)

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'60 days

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'

'

'

'

'

'

'

'

Customers greater than 10% of total

'

'

22.70%

24.20%

21.60%

23.90%

20.40%

33.80%

42.20%

43.80%

43.30%

42.60%

35.90%

22.60%

13.00%

11.20%

12.40%

12.50%

17.00%

19.90%

Balance_Sheet_Components_Accou

Balance Sheet Components - Accounts receivable (Details) (USD $)	Dec. 31, 2013	Jun. 30, 2013
In Thousands, unless otherwise specified
Balance Sheet Related Disclosures [Abstract]	'	'
Accounts receivable	$54,099	$52,202
Less: allowance for price adjustments	-15,067	-13,152
Less: allowance for doubtful accounts	-30	-752
Accounts receivable, net	$39,002	$38,298

Balance_Sheet_Components_Inven

Balance Sheet Components - Inventories (Details) (USD $)	Dec. 31, 2013	Jun. 30, 2013
In Thousands, unless otherwise specified
Balance Sheet Related Disclosures [Abstract]	'	'
Raw materials	$17,445	$17,248
Work in-process	36,165	38,618
Finished goods	9,157	12,473
Inventory, net	$62,767	$68,339

Balance_Sheet_Components_Prope

Balance Sheet Components - Property, plant, and equipment (Details) (USD $)	Dec. 31, 2013	Jun. 30, 2013
In Thousands, unless otherwise specified
Property, Plant and Equipment [Line Items]	'	'
Property, plant, and equipment excluding equipment and construction In progress, gross	$221,640	$218,137
Less accumulated depreciation	-100,932	-87,180
Property, plant and equipment excluding equipment and construction in progress, net	120,708	130,957
Equipment and construction in progress	6,800	7,154
Property, plant and equipment, net	127,508	138,111
Land	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, plant, and equipment excluding equipment and construction In progress, gross	4,950	4,950
Building	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, plant, and equipment excluding equipment and construction In progress, gross	4,106	4,106
Manufacturing machinery and equipment	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, plant, and equipment excluding equipment and construction In progress, gross	159,338	156,958
Equipment and tooling	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, plant, and equipment excluding equipment and construction In progress, gross	10,413	10,356
Computer equipment and software	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, plant, and equipment excluding equipment and construction In progress, gross	16,835	16,140
Office furniture and equipment	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, plant, and equipment excluding equipment and construction In progress, gross	1,564	1,559
Leasehold improvements	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, plant, and equipment excluding equipment and construction In progress, gross	$24,434	$24,068

Balance_Sheet_Components_Other

Balance Sheet Components - Other long term assets (Details) (USD $)	Dec. 31, 2013	Jun. 30, 2013
In Thousands, unless otherwise specified
Balance Sheet Related Disclosures [Abstract]	'	'
Prepayments for property and equipment	$707	$77
Investment in a priveately held company	100	100
Deferred debt issuance cost	43	91
Office leases deposits	411	499
Other long-term assets	$1,261	$767

Balance_Sheet_Components_Accru

Balance Sheet Components - Accrued liabilites (Details) (USD $)	Dec. 31, 2013	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012
In Thousands, unless otherwise specified
Balance Sheet Related Disclosures [Abstract]	'	'	'	'
Accrued salaries and wages	$4,216	$3,079	'	'
Accrued vacation	968	2,078	'	'
Accrued bonuses	1,153	880	'	'
Warranty accrual	1,496	1,428	1,673	1,556
Stock rotation accrual	1,480	1,572	1,767	2,032
Accrued professional fees	607	918	'	'
ESPP payable	290	353	'	'
Customer deposits	488	123	'	'
Other accrued expenses	4,674	4,140	'	'
Accrued liabilities	$15,372	$14,571	'	'

Balance_Sheet_Components_Produ

Balance Sheet Components - Product Warranty Accrual (Details) (USD $)	6 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Movement in Standard and Extended Product Warranty, Increase (Decrease) [Roll Forward]	'	'
Beginning balance	$1,428	$1,556
Additions	1,239	733
Utilization	-1,171	-616
Ending balance	$1,496	$1,673

Balance_Sheet_Components_Stock

Balance Sheet Components - Stock Rotation Accrual (Details) (USD $)	6 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Stock Rotation Accrual Increae (Decrease) [Roll Forward]	'	'
Beginning balance	$1,572	$2,032
Additions	2,332	3,254
Utilzation	-2,424	-3,519
Ending balance	$1,480	$1,767

Debt_Details

Debt - (Details)

6 Months Ended

6 Months Ended

6 Months Ended

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Jun. 30, 2013

11-May-12

Dec. 31, 2013

Jun. 30, 2013

Jul. 17, 2012

Dec. 31, 2013

Dec. 31, 2013

USD ($)

CNY

Federal funds rate

Eurodollar rate

Minimum

Minimum

Maximum

Maximum

CHINA

Variable Interest Rate Term Loan Maturing May 2015

Variable Interest Rate Term Loan Maturing May 2015

Variable Interest Rate Term Loan Maturing May 2015

State of Oregon Loan

State of Oregon Loan

State of Oregon Loan

Subsidiaries [Member]

Subsidiaries [Member]

Subsidiaries

Subsidiaries

LIBOR rate

Margin Rate

LIBOR rate

Margin Rate

Subsidiaries

Notes Payable to Banks

Notes Payable to Banks

Notes Payable to Banks

Loans Payable

Loans Payable

Loans Payable

USD ($)

Maximum

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Line of Credit Facility, Amount Outstanding

'

'

'

'

'

'

'

'

'

'

'

$0

'

'

'

$0

'

Loan, principal amount

'

'

'

'

'

'

'

'

'

'

'

20,000,000

'

'

250,000

'

'

Line of Credit Facility, Maximum Borrowing Capacity

15,700,000

95,000,000

'

'

'

'

'

'

'

'

'

10,000,000

'

'

'

'

'

Debt instrument, basis spread on variable rate

'

'

0.50%

1.00%

1.00%

-0.50%

1.75%

0.25%

'

'

'

'

'

'

'

'

'

Outstanding balance of loan

'

'

'

'

'

'

'

'

'

15,000,000

17,100,000

'

269,000

262,000

'

'

'

Outstanding balance of loan due in the next 12 months

'

'

'

'

'

'

'

'

'

$2,900,000

$3,600,000

'

'

'

'

'

'

Number of subsidiaries securing obligations under loan agreement

2

2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of subsidiaries with revolving lines of credit

'

'

'

'

'

'

'

'

2

'

'

'

'

'

'

'

'

Line of credit facility, subsidiaries, borrowing capacity, maximum percent of accounts receivable

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

80.00%

Repayment term of line of credit (in days)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'120 days

Interest rate on loan

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5.00%

'

'

Shareholders_Equity_and_Shareb2

Shareholders' Equity and Share-based Compensation - Shares Repurchase (Details) (USD $)	0 Months Ended	3 Months Ended	6 Months Ended	38 Months Ended
In Millions, except Share data, unless otherwise specified	Oct. 22, 2010	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013
Class of Stock [Line Items]	'	'	'	'
Share repurchase program, authorized amount (USD in Millions)	$25	'	'	'
Treasury stock acquired, shares repurchased (in shares)	'	0	0	241,770
Treasury stock acquired, average price per share (in dollars per share)	'	'	'	$9.40
Treasury stock acquired (USD In Millions)	'	'	'	$2.30
Treasury Stock Reissued	'	'	'	'
Class of Stock [Line Items]	'	'	'	'
Treasury stock acquired, average price per share (in dollars per share)	'	13.82	13.82	$13.81
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures (in shares)	'	2,700	2,950	18,750
Treasury stock reissued, average price per share (in dollars per share)	'	'	'	$3.47

Shareholders_Equity_and_Shareb3

Shareholders' Equity and Share-based Compensation - Share-based Compensation (Details) (USD $)	3 Months Ended	6 Months Ended	38 Months Ended
	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Jun. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Treasury stock acquired, shares repurchased (in shares)	0	0	241,770	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]	'	'	'	'
Outstanding at June 30, 2013 (in shares)	'	3,593,854	'	'
Granted (in shares)	'	77,500	'	'
Exercised (in shares)	'	-119,321	'	'
Canceled or forfeited (in shares)	'	-237,461	'	'
Outstanding at December 31, 2013 (in shares)	3,314,572	3,314,572	3,314,572	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]	'	'	'	'
Outstanding at June 30, 2013 (in dollars per share)	'	$10.24	'	'
Granted (in dollars per share)	'	$7.51	'	'
Exercised (in dollars per share)	'	$0.98	'	'
Canceled or forfeited (in dollars per share)	'	$11.18	'	'
Outstanding at December 31, 2013 (in dollars per share)	$10.45	$10.45	$10.45	'
Options Outstanding Aggregate Intrinsic Value	$2,409,612	$2,409,612	$2,409,612	$3,144,506
Options Exercised Aggegate Intrinsic Value	'	$772,342	'	'
Employee Stock [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Volatility Rate	'	50.00%	'	'
Expected Term	'	'1 year 3 months 18 days	'	'
Expected Dividend Rate	'	0.00%	'	'
Employee Stock [Member] | Minimum	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Risk Free Interest Rate	'	0.10%	'	'
Employee Stock [Member] | Maximum	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Risk Free Interest Rate	'	0.30%	'	'
Stock Options [Member]	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Volatility Rate	'	48.00%	'	'
Expected Term	'	'5 years 6 months	'	'
Expected Dividend Rate	'	0.00%	'	'
Stock Options [Member] | Minimum	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Risk Free Interest Rate	'	1.60%	'	'
Stock Options [Member] | Maximum	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'
Risk Free Interest Rate	'	1.70%	'	'

Shareholders_Equity_and_Shareb4

Shareholders' Equity and Share-based Compensation - Stock Options Outstanding and Exercisable (Details) (USD $)	6 Months Ended
	Dec. 31, 2013	Jun. 30, 2013
Share-based Compensation [Abstract]	'	'
Options, Number Outstanding (in shares)	3,314,572	3,593,854
Options, Weighted-Average Remaining Contractual Life (in years)	'4 years 5 months 5 days	'
Options, Weighted-Average Exercise Price (in dollars per share)	$10.45	$10.24
Options, Number Exercisable (in shares)	2,778,724	'
Options, Weighted-Average Exercise Price (in dollars per share)	$10.29	'
Options vested and expected to vest, Number Outstanding (in shares)	3,280,477	'
Options vested and expected to vest, Weighted Average Remaining Contractual Life (in years)	'4 years 4 months 10 days	'
Options vested and expected to vest, Weighted Average Exercise Price (in dollars per share)	$10.44	'

Shareholders_Equity_and_Shareb5

Shareholders' Equity and Share-based Compensation - Restricted Stock Activity (Details) (USD $)	6 Months Ended	12 Months Ended
	Dec. 31, 2013	Jun. 30, 2013
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 3 months 18 days	'
Restricted Stock	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]	'	'
Nonvested	549,553	'
Granted	55,804	'
Vested	-71,960	'
Forfeited	-73,952	'
Nonvested	459,445	549,553
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]	'	'
Nonvested	$9.50	'
Granted	$7.65	'
Vested	$9.65	'
Forfeited	$9.72	'
Nonvested	$9.22	$9.50
Weighted Average Remaining Recognition Period (Years)	'1 year 8 months 1 day	'1 year 10 months 13 days
RSUs Nonvested Aggregate Intrinsic Value	$3,542,321	$4,198,585
RSUs vested and expected to vest, Outstanding (in shares)	415,616	'
RSUs vested and expected to vest, Weighted Average Remaining Recognition Period (in years)	'1 year 7 months 6 days	'
RSUs vested and expected to vest, Aggregate Intrinsic Value	$3,204,396	'

Shareholders_Equity_and_Shareb6

Shareholders' Equity and Share-based Compensation - Share-based Compensation Expenses (Details) (USD $)	3 Months Ended		6 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Allocated share-based compensation expense	$105,000	$913,000	$1,314,000	$2,354,000
Unrecognized compensation expense	3,800,000	'	3,800,000	'
Recognition period of share-based compensation expense (in years)	'	'	'1 year 3 months 18 days	'
Cost of goods sold	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Allocated share-based compensation expense	142,000	141,000	338,000	339,000
Research and development	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Allocated share-based compensation expense	-32,000	278,000	263,000	671,000
Selling, general and administrative	'	'	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'	'	'
Allocated share-based compensation expense	($5,000)	$494,000	$713,000	$1,344,000

Income_Taxes_Narrative_Details

Income Taxes - Narrative (Details) (USD $)	3 Months Ended		6 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]	'	'	'	'
Income tax expense	$1,123,000	$1,085,000	$2,125,000	$2,897,000
Estimated effective income tax rate	87.50%	22.60%	82.00%	19.90%
Unrecognized tax benefits	$7,600,000	'	$7,600,000	'

Segment_and_Geographic_Informa2

Segment and Geographic Information - Revenue by Location and Product Type (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Revenue	$76,265	$89,448	$160,386	$185,209
Power discrete	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Revenue	58,946	70,801	124,091	146,305
Power IC	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Revenue	13,226	12,936	26,838	27,467
Packaging and testing services	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Revenue	4,093	5,711	9,457	11,437
Hong Kong	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Revenue	64,229	71,251	135,485	145,878
China	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Revenue	10,156	15,336	21,048	32,965
South Korea	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Revenue	745	1,392	1,542	3,660
United States	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Revenue	425	313	898	656
Other countries	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'
Revenue	$710	$1,156	$1,413	$2,050

Segment_and_Geographic_Informa3

Segment and Geographic Information - Long-lived Assets (Details) (USD $)	Dec. 31, 2013	Jun. 30, 2013
In Thousands, unless otherwise specified
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Property, plant and equipment, net	$127,508	$138,111
China	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Property, plant and equipment, net	85,704	93,663
United States	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Property, plant and equipment, net	41,389	43,946
Other countries	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Property, plant and equipment, net	$415	$502

Segment_and_Geographic_Informa4

Segment and Geographic Information - Narratives (Details)	6 Months Ended
	Dec. 31, 2013
	Segment
Segment Reporting [Abstract]	'
Number of operating segments	1
Number of reportable segments	1

Commitments_and_Contingencies_

Commitments and Contingencies - Purchase Commitments (Details) (USD $)	Dec. 31, 2013	Jun. 30, 2013
In Millions, unless otherwise specified
Raw materials, wafers, and packaging and testing services puchase commitments	'	'
Purchase Commitment, Excluding Long-term Committment [Line Items]	'	'
Purchase commitment, amount	$30	$25.80
Property and equipment purchase commitments	'	'
Purchase Commitment, Excluding Long-term Committment [Line Items]	'	'
Purchase commitment, amount	$4.20	$0.40

Commitments_and_Contingencies_1

Commitments and Contingencies - Guarantees (Details) (Indemnification Agreement, USD $)	Dec. 31, 2013	Jun. 30, 2013
Indemnification Agreement	'	'
Loss Contingencies [Line Items]	'	'
Indemnifications accrual	$0	$0