Alpha and Omega Semiconductor Limited (AOSL) 10-Q 7 Nov 14 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Sep. 30, 2014	Oct. 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	30-Sep-14	'
Document Fiscal Year Focus	'2015	'
Document Fiscal Period Focus	'Q1	'
Amendment Flag	'false	'
Entity Common Stock, Shares Outstanding	'	26,451,629

CONDENSED_CONSOLIDATED_BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (USD $)	Sep. 30, 2014	Jun. 30, 2014
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$117,834	$117,788
Restricted cash	366	244
Accounts receivable, net	35,066	36,535
Inventories	68,410	66,560
Deferred income tax assets	1,423	2,842
Other current assets	3,873	3,810
Total current assets	226,972	227,779
Property, plant and equipment, net	120,899	123,254
Intangible assets, net	66	229
Goodwill	269	269
Deferred income tax assets-long term	10,931	10,854
Other long-term assets	2,283	1,963
Total assets	361,420	364,348
Current liabilities:	'	'
Short term debt	7,857	13,821
Accounts payable	40,487	38,760
Accrued liabilities	17,277	17,376
Income taxes payable	2,384	1,933
Deferred margin	745	665
Capital leases	1,051	1,061
Total current liabilities	69,801	73,616
Income taxes payable - long term	2,336	2,315
Deferred income tax liabilities	1,947	3,234
Capital leases - long term	779	1,005
Other long term liabilities	1,099	1,143
Total liabilities	75,962	81,313
Commitments and contingencies (Note 9)	'	'
Preferred shares, par value $0.002 per share:	'	'
Authorized: 10,000 shares, issued and outstanding: none at September 30, 2014 and June 30, 2014	0	0
Common shares, par value $0.002 per share:	'	'
Authorized: 50,000 shares, issued and outstanding: 26,786 shares and 26,446 shares at September 30, 2014 and 26,644 shares and 26,304 shares at June 30, 2014	54	53
Treasury shares at cost, 340 shares at September 30, 2014 and 340 shares at June 30, 2014	-2,889	-2,889
Additional paid-in capital	175,990	174,084
Accumulated other comprehensive income	985	1,033
Retained earnings	111,318	110,754
Total shareholders’ equity	285,458	283,035
Total liabilities and shareholders’ equity	$361,420	$364,348

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Sep. 30, 2014	Jun. 30, 2014
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)	26,786,000	26,644,000
Common stock, shares outstanding (in shares)	26,446,000	26,304,000
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)	340,000	340,000

CONDENSED_CONSOLIDATED_STATEME

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Revenue	$88,217	$84,121
Cost of goods sold	70,057	66,970
Gross profit	18,160	17,151
Operating expenses	'	'
Research and development	6,796	6,847
Selling, general and administrative	9,604	8,940
Total operating expenses	16,400	15,787
Operating income	1,760	1,364
Interest income and other, net	48	24
Interest expense	-73	-79
Income before income taxes	1,735	1,309
Income tax expense	1,171	1,002
Net income	$564	$307
Net income per share	'	'
Basic (in dollars per share)	$0.02	$0.01
Diluted (in dollars per share)	$0.02	$0.01
Weighted average number of common shares used to compute net income per share	'	'
Basic (in shares)	26,385	25,684
Diluted (in shares)	27,003	26,309

CONDENSED_CONSOLIDATED_STATEME1

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Net income	$564	$307
Foreign currency translation adjustment	-48	54
Total comprehensive income	$516	$361

CONDENSED_CONSOLIDATED_STATEME2

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Cash flows from operating activities	'	'
Net income	$564	$307
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Depreciation	6,955	6,927
Amortization	91	103
Allowance for doubtful accounts	0	-363
Share-based compensation expense	1,102	1,209
Deferred income taxes, net	54	378
(Gain) loss on disposal of property and equipment	22	-74
Forgiveness of loan	-250	0
Changes in assets and liabilities:	'	'
Accounts receivable	1,469	-2,288
Inventories	-1,849	-83
Other current and long-term assets	-383	-541
Accounts payable	-515	712
Income taxes payable	472	-451
Accrued and other liabilities	-103	904
Net cash provided by operating activities	7,629	6,740
Cash flows from investing activities	'	'
Purchases of property and equipment	-2,345	-1,578
Proceeds from sale of property and equipment	0	194
Restricted cash placed	-122	-42
Net cash used in investing activities	-2,467	-1,426
Cash flows from financing activities	'	'
Proceeds from exercise of stock options	858	23
Repayments of borrowings	-5,714	-1,429
Principal payments on capital leases	-237	-333
Net cash used in financing activities	-5,093	-1,739
Effect of exchange rate changes on cash and cash equivalents	-23	14
Net increase in cash and cash equivalents	46	3,589
Cash and cash equivalents at beginning of period	117,788	92,406
Cash and cash equivalents at end of period	117,834	95,995
Supplemental disclosures of non-cash investing and financing information:	'	'
Property and equipment purchased but not yet paid	5,594	2,157
Re-issuance of treasury stock	$0	$4

The_Company_and_Significant_Ac

The Company and Significant Accounting Policies	3 Months Ended
	Sep. 30, 2014
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, 2014. 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 months ended September 30, 2014 are not necessarily indicative of the results that may be expected for the fiscal year ending June 30, 2015. The condensed consolidated balance sheet at June 30, 2014 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, 2014.
	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. 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 (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 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. ASU 2014-09 is effective for annual reporting periods beginning after December 15, 2016. Early adoption is not permitted. The guidance permits companies 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 impact of adoption on its consolidated financial statements.

Net_Income_Per_Share

Net Income Per Share	3 Months Ended
	Sep. 30, 2014
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 September 30,
		2014			2013
		(in thousands, except per share data)
	Numerator:
	Net income	$	564		$	307
	Denominator:
	Basic:
	Weighted average number of common shares used to compute basic net income per share	26,385			25,684
	Diluted:
	Weighted average number of common shares used to compute basic net income per share	26,385			25,684
	Effect of potentially dilutive securities:
	Stock options, RSUs and ESPP shares	618			625
	Weighted average number of common shares used to compute diluted net income per share	27,003			26,309
	Net income per share:
	Basic	$	0.02		$	0.01
	Diluted	$	0.02		$	0.01
	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 September 30,
		2014		2013
		(in thousands)
	Employee stock options and RSUs	2,393		2,783
	ESPP to purchase common shares	—		307
	Total potential dilutive securities	2,393		3,090

Concentration_of_Credit_Risk_a

Concentration of Credit Risk and Significant Customers	3 Months Ended
	Sep. 30, 2014
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 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 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 September 30,
	Percentage of revenue	2014		2013
	Customer A	24.1	%	20.6	%
	Customer B	39.6	%	44.3	%
	Customer C	12.9	%	11.8	%
		September 30,		June 30,
	Percentage of accounts receivable	2014		2014
	Customer A	32.6	%	23.1	%
	Customer B	15.6	%	30.5	%
	Customer C	24.7	%	17.4	%

Balance_Sheet_Components

Balance Sheet Components	3 Months Ended
	Sep. 30, 2014
Balance Sheet Related Disclosures [Abstract]	'
Balance Sheet Components	'
	Balance Sheet Components
	Accounts receivable:
		September 30,			June 30,
		2014			2014
		(in thousands)
	Accounts receivable	$	50,657		$	51,128
	Less: Allowance for price adjustments	(15,561		)	(14,563		)
	Less: Allowance for doubtful accounts	(30		)	(30		)
	Accounts receivable, net	$	35,066		$	36,535
	Inventories:
		September 30,			June 30,
		2014			2014
		(in thousands)
	Raw materials	$	18,539		$	18,996
	Work in-process	38,642			36,003
	Finished goods	11,229			11,561
		$	68,410		$	66,560
	Property, plant and equipment, net:
		September 30,			June 30,
		2014			2014
		(in thousands)
	Land	$	4,950		$	4,950
	Building	4,241			4,106
	Manufacturing machinery and equipment	163,854			161,354
	Equipment and tooling	10,644			10,486
	Computer equipment and software	19,689			19,319
	Office furniture and equipment	1,639			1,643
	Leasehold improvements	25,386			25,154
		230,403			227,012
	Less: Accumulated depreciation	(121,543		)	(114,658		)
		108,860			112,354
	Equipment and construction in progress	12,039			10,900
	Property, plant and equipment, net	$	120,899		$	123,254
	Other long-term assets:
		September 30,			June 30,
		2014			2014
		(in thousands)
	Prepayments for property and equipment	$	1,782		$	1,435
	Investment in a privately held company	100			100
	Office leases deposits	401			428
		$	2,283		$	1,963
	Accrued liabilities:
		September 30,			June 30,
		2014			2014
		(in thousands)
	Accrued compensation and benefit	$	3,897		$	4,879
	Accrued vacation	1,973			1,777
	Accrued bonuses	1,947			1,873
	Warranty accrual	1,230			1,346
	Stock rotation accrual	1,607			1,645
	Accrued professional fees	1,175			1,001
	ESPP payable	810			323
	Customer deposits	102			104
	Accrued inventory	450			590
	Accrued facilities related expenses	1,570			1,353
	Other accrued expenses	2,516			2,485
		$	17,277		$	17,376
	The activities in the warranty accrual, included in accrued liabilities, are as follows:
		Three Months Ended September 30,
		2014			2013
		(in thousands)
	Beginning balance	$	1,346		$	1,428
	Additions	530			285
Utilization	(646		)	(352		)
Ending balance	$	1,230		$	1,361
The activities in the stock rotation accrual, included in accrued liabilities, are as follows:
	Three Months Ended September 30,
	2014			2013
	(in thousands)
Beginning balance	$	1,645		$	1,572
Additions	1,294			1,346
Utilization	(1,332		)	(1,321		)
Ending balance	$	1,607		$	1,597
Other Long-term liabilities:
	September 30,			June 30,
	2014			2014
	(in thousands)
Deferred rent	$	1,096		$	1,143
Customer deposit	3			—
	$	1,099		$	1,143

Debt

Debt	3 Months Ended
	Sep. 30, 2014
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 September 30, 2014 and June 30, 2014, the outstanding balances of the term loan were $7.9 million and $13.6 million, respectively.
	The obligations under the loan agreement 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 September 30, 2014, the Company was in compliance with these covenants.
	During July 2012, the Company entered into a loan agreement with the State of Oregon for an amount of $0.3 million. The loan was required to be used for training new and re-training existing employees of the Oregon fab. The loan bore a compound annual interest rate of 5.0% and was to be repaid in April 2014 if the required conditions were not met. In September 2014, the State of Oregon forgave the outstanding balance in full as we had satisfied the conditions. The $0.3 million loan forgiven was recorded as a reduction of costs of goods sold in our condensed consolidated statements of operations. There was no outstanding balance of the loan as of September 30, 2014.

Shareholders_Equity_and_Shareb

Shareholders' Equity and Share-based Compensation	3 Months Ended
	Sep. 30, 2014
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.
	On May 8, 2014, the Company's Board of Directors approved to reactivate the share repurchase program with a remaining balance of $22.7 million. The Board authorized management to repurchase, subject to oversight by the Board, our common shares up to the remaining balance of the program, or $22.7 million. The repurchases may be made from the open market or through negotiated block transactions and to date repurchases have been made pursuant to a pre-established 10b5-1 trading plan. Such 10b5-1 trading plan was expired in August 2014 and the Board intends to review conditions from time to time to determine whether it is appropriate to implement a new 10b5-1 trading plan or to conduct repurchases under the program outside of a 10b5-1 trading plan.
	During the three months ended September 30, 2014, the Company did not repurchased any shares under the program. As of September 30, 2014, the Company repurchased an aggregate of 361,364 shares for a total cost of $3.2 million, at an average repurchase price of $8.82 per share since inception of the program. No repurchased shares have been retired. Of the 361,364 repurchased shares, 21,650 shares with a weighted average repurchase price of $13.81 per share, were reissued at an average price of $3.00 per share for option exercises and vested RSU.
	Stock Options
	The following table summarizes the Company's stock option activities for the three months ended September 30, 2014:
				Weighted
				Average
		Number of		Exercise Price				Aggregate
		Shares		Per Share				Intrinsic Value
	Outstanding at June 30, 2014	3,238,784		$	10.28			$	3,258,607
	Granted	10,000		$	9.07
	Exercised	(128,231	)	$	6.69			$	392,484
	Canceled or forfeited	(17,484	)	$	15.87
	Outstanding at September 30, 2014	3,103,069		$	10.4			$	3,118,240
	Information with respect to stock options outstanding and exercisable at September 30, 2014 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	3,103,069		5.68		$	10.4			2,115,149		$	11.26
	Options vested and expected to vest	3,005,766		5.57		$	10.48
	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 three months ended September 30, 2014 with the following weighted average assumptions:
		Three Months Ended September 30,
		2014
	Volatility rate	43.50%
	Risk-free interest rate	1.70%
	Expected term	5.5 years
	Dividend yield	0%
	Historically, the Company estimates its expected volatility based on that of the publicly traded shares of industry peers over a period equivalent to the expected term of the stock awards granted. Beginning in July 2015, the Company estimates its expected volatility based on a weighted average calculation of both the Company's volatility of its publicly traded share prices since its IPO and that of the publicly traded shares of industry peers over a period equivalent to the expected term of the stock awards granted.
	Restricted Stock Units ("RSU")
	The following table summarizes the Company's RSU activities for the three months ended September 30, 2014:
		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, 2014	656,374		$	8.4			1.77		$	6,084,587
	Granted	25,500		$	9.48
	Vested	(19,674	)	$	8.92
	Forfeited	(29,950	)	$	8.41
	Nonvested at September 30, 2014	632,250		$	8.43			1.61		$	5,943,150
	RSUs vested and expected to vest	557,582						1.52		$	5,241,267
	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:
		Three Months Ended September 30,
		2014
	Volatility rate	50%
	Risk-free interest rate	0.1% - 0.4%
	Expected term	1.3 years
	Dividend yield	0%
	Share-based Compensation Expense
	The total share-based compensation expense 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 September 30,
		2014			2013
		(in thousands)
	Cost of goods sold	$	154		$	196
	Research and development	206			295
	Selling, general and administrative	742			718
		$	1,102		$	1,209
	Total unrecognized stock-based compensation expense as of September 30, 2014 was $4.7 million, which includes estimated forfeitures and is expected to be recognized over a weighted-average period of 1.4 years.

Income_Taxes

Income Taxes	3 Months Ended
	Sep. 30, 2014
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	Income Taxes
	The Company recognized income tax expense of approximately $1.2 million and $1.0 million for the three months ended September 30, 2014 and 2013, respectively. The estimated effective tax rate for the three months ended September 30, 2014 was 67.5% compared to 76.5% for the three months ended September 30, 2013. The effective tax rate for the three months ended September 30, 2014 was lower than the effective tax rate for the same period 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 2014 remain open to examination by U.S. federal and state tax authorities. The tax years 2005 to 2014 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, 2014, the gross amount of unrecognized tax benefits was approximately $6.8 million, of which $4.8 million that, 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.

Segment_and_Geographic_Informa

Segment and Geographic Information	3 Months Ended
	Sep. 30, 2014
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 September 30,
		2014		2013
		(in thousands)
	Hong Kong	$	75,247	$	71,256
	China	10,957		10,892
	South Korea	639		797
	United States	683		473
	Other countries	691		703
		$	88,217	$	84,121
	The following is a summary of revenue by product type:
		Three Months Ended September 30,
		2014		2013
		(in thousands)
	Power discrete	$	64,891	$	65,145
	Power IC	19,156		13,612
	Packaging and testing services	4,170		5,364
		$	88,217	$	84,121
	Long-lived assets, net consisting of property, plant and equipment, by geographical area are as follows:
		September 30,		June 30,
		2014		2014
		(in thousands)
	China	$	79,262	$	80,736
	United States	41,245		42,106
	Other Countries	392		412
		$	120,899	$	123,254

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Sep. 30, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingencies	'
	Commitments and Contingencies
	Purchase Commitments
	As of September 30, 2014 and June 30, 2014, the Company had approximately $20.6 million and $34.5 million, respectively, of outstanding purchase commitments primarily for purchases of semiconductor raw materials, wafers, spare parts and packaging and testing services, and approximately $2.5 million and $4.6 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, 2014 and June 30, 2014.
	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)	3 Months Ended
	Sep. 30, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
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 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 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, 2014. 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 months ended September 30, 2014 are not necessarily indicative of the results that may be expected for the fiscal year ending June 30, 2015. The condensed consolidated balance sheet at June 30, 2014 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, 2014.
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. 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 (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 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. ASU 2014-09 is effective for annual reporting periods beginning after December 15, 2016. Early adoption is not permitted. The guidance permits companies 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 impact of adoption on its consolidated financial statements.

Net_Income_Per_Share_Tables

Net Income Per Share (Tables)	3 Months Ended
	Sep. 30, 2014
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 September 30,
		2014			2013
		(in thousands, except per share data)
	Numerator:
	Net income	$	564		$	307
	Denominator:
	Basic:
	Weighted average number of common shares used to compute basic net income per share	26,385			25,684
	Diluted:
	Weighted average number of common shares used to compute basic net income per share	26,385			25,684
	Effect of potentially dilutive securities:
	Stock options, RSUs and ESPP shares	618			625
	Weighted average number of common shares used to compute diluted net income per share	27,003			26,309
	Net income per share:
	Basic	$	0.02		$	0.01
	Diluted	$	0.02		$	0.01
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 September 30,
		2014		2013
		(in thousands)
	Employee stock options and RSUs	2,393		2,783
	ESPP to purchase common shares	—		307
	Total potential dilutive securities	2,393		3,090

Concentration_of_Credit_Risk_a1

Concentration of Credit Risk and Significant Customers (Tables)	3 Months Ended
	Sep. 30, 2014
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 September 30,
	Percentage of revenue	2014		2013
	Customer A	24.1	%	20.6	%
	Customer B	39.6	%	44.3	%
	Customer C	12.9	%	11.8	%
		September 30,		June 30,
	Percentage of accounts receivable	2014		2014
	Customer A	32.6	%	23.1	%
	Customer B	15.6	%	30.5	%
	Customer C	24.7	%	17.4	%

Balance_Sheet_Components_Table

Balance Sheet Components (Tables)	3 Months Ended
	Sep. 30, 2014
Balance Sheet Related Disclosures [Abstract]	'
Schedule of Accounts, Notes, Loans and Financing Receivable	'
	Accounts receivable:
		September 30,			June 30,
		2014			2014
		(in thousands)
	Accounts receivable	$	50,657		$	51,128
	Less: Allowance for price adjustments	(15,561		)	(14,563		)
	Less: Allowance for doubtful accounts	(30		)	(30		)
	Accounts receivable, net	$	35,066		$	36,535
Schedule of Inventory, Current	'
	Inventories:
		September 30,			June 30,
		2014			2014
		(in thousands)
	Raw materials	$	18,539		$	18,996
	Work in-process	38,642			36,003
	Finished goods	11,229			11,561
		$	68,410		$	66,560
Property, Plant and Equipment	'
	Property, plant and equipment, net:
		September 30,			June 30,
		2014			2014
		(in thousands)
	Land	$	4,950		$	4,950
	Building	4,241			4,106
	Manufacturing machinery and equipment	163,854			161,354
	Equipment and tooling	10,644			10,486
	Computer equipment and software	19,689			19,319
	Office furniture and equipment	1,639			1,643
	Leasehold improvements	25,386			25,154
		230,403			227,012
	Less: Accumulated depreciation	(121,543		)	(114,658		)
		108,860			112,354
	Equipment and construction in progress	12,039			10,900
	Property, plant and equipment, net	$	120,899		$	123,254
Schedule of Other Assets, Noncurrent	'
	Other long-term assets:
		September 30,			June 30,
		2014			2014
		(in thousands)
	Prepayments for property and equipment	$	1,782		$	1,435
	Investment in a privately held company	100			100
	Office leases deposits	401			428
		$	2,283		$	1,963
Schedule of Accrued Liabilities	'
	Accrued liabilities:
		September 30,			June 30,
		2014			2014
		(in thousands)
	Accrued compensation and benefit	$	3,897		$	4,879
	Accrued vacation	1,973			1,777
	Accrued bonuses	1,947			1,873
	Warranty accrual	1,230			1,346
	Stock rotation accrual	1,607			1,645
	Accrued professional fees	1,175			1,001
	ESPP payable	810			323
	Customer deposits	102			104
	Accrued inventory	450			590
	Accrued facilities related expenses	1,570			1,353
	Other accrued expenses	2,516			2,485
		$	17,277		$	17,376
Schedule of Product Warranty Liability	'
	The activities in the warranty accrual, included in accrued liabilities, are as follows:
		Three Months Ended September 30,
		2014			2013
		(in thousands)
	Beginning balance	$	1,346		$	1,428
	Additions	530			285
	Utilization	(646		)	(352		)
	Ending balance	$	1,230		$	1,361
Stock Rotation Accrual	'
	The activities in the stock rotation accrual, included in accrued liabilities, are as follows:
		Three Months Ended September 30,
		2014			2013
		(in thousands)
	Beginning balance	$	1,645		$	1,572
	Additions	1,294			1,346
	Utilization	(1,332		)	(1,321		)
	Ending balance	$	1,607		$	1,597
Schedule of Other Noncurrent Liabilities	'
	Other Long-term liabilities:
		September 30,			June 30,
		2014			2014
		(in thousands)
	Deferred rent	$	1,096		$	1,143
	Customer deposit	3			—
		$	1,099		$	1,143

Shareholders_Equity_and_Shareb1

Shareholders' Equity and Share-based Compensation (Tables)	3 Months Ended
	Sep. 30, 2014
Share-based Compensation [Abstract]	'
Summary of Stock Option Activities	'
	Stock Options
	The following table summarizes the Company's stock option activities for the three months ended September 30, 2014:
				Weighted
				Average
		Number of		Exercise Price				Aggregate
		Shares		Per Share				Intrinsic Value
	Outstanding at June 30, 2014	3,238,784		$	10.28			$	3,258,607
	Granted	10,000		$	9.07
	Exercised	(128,231	)	$	6.69			$	392,484
	Canceled or forfeited	(17,484	)	$	15.87
	Outstanding at September 30, 2014	3,103,069		$	10.4			$	3,118,240
	Information with respect to stock options outstanding and exercisable at September 30, 2014 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	3,103,069		5.68		$	10.4			2,115,149		$	11.26
	Options vested and expected to vest	3,005,766		5.57		$	10.48
	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 three months ended September 30, 2014 with the following weighted average assumptions:
		Three Months Ended September 30,
		2014
	Volatility rate	43.50%
	Risk-free interest rate	1.70%
	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 three months ended September 30, 2014:
		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, 2014	656,374		$	8.4			1.77		$	6,084,587
	Granted	25,500		$	9.48
	Vested	(19,674	)	$	8.92
	Forfeited	(29,950	)	$	8.41
	Nonvested at September 30, 2014	632,250		$	8.43			1.61		$	5,943,150
	RSUs vested and expected to vest	557,582						1.52		$	5,241,267
	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:
		Three Months Ended September 30,
		2014
	Volatility rate	50%
	Risk-free interest rate	0.1% - 0.4%
	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, ESPP and RSUs described above, recognized in the condensed consolidated statements of operations for the periods presented was as follows:
		Three Months Ended September 30,
		2014			2013
		(in thousands)
	Cost of goods sold	$	154		$	196
	Research and development	206			295
	Selling, general and administrative	742			718
		$	1,102		$	1,209

Segment_and_Geographic_Informa1

Segment and Geographic Information (Tables)	3 Months Ended
	Sep. 30, 2014
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,		June 30,
		2014		2014
		(in thousands)
	China	$	79,262	$	80,736
	United States	41,245		42,106
	Other Countries	392		412
		$	120,899	$	123,254
	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,
		2014		2013
		(in thousands)
	Hong Kong	$	75,247	$	71,256
	China	10,957		10,892
	South Korea	639		797
	United States	683		473
	Other countries	691		703
		$	88,217	$	84,121
Revenue from External Customers by Products and Services	'
	The following is a summary of revenue by product type:
		Three Months Ended September 30,
		2014		2013
		(in thousands)
	Power discrete	$	64,891	$	65,145
	Power IC	19,156		13,612
	Packaging and testing services	4,170		5,364
		$	88,217	$	84,121

Net_Income_Per_Share_Basic_and

Net Income Per Share - Basic and Diluted Income Per Share (Details) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Numerator:	'	'
Net income	$564	$307
Basic:	'	'
Weighted average number of common shares used to compute basic net income per share	26,385	25,684
Effect of potentially dilutive securities:	'	'
Stock options, RSUs and ESPP shares (in shares)	618	625
Weighted average number of common shares used to compute diluted net income per share	27,003	26,309
Net income per share:	'	'
Basic (in dollars per share)	$0.02	$0.01
Diluted (in dollars per share)	$0.02	$0.01

Net_Income_Per_Share_Potential

Net Income Per Share - Potential Dilutive Shares (Details)	3 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Potential dilutive securities (in shares)	2,393	3,090
Employee stock options and RSUs	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Potential dilutive securities (in shares)	2,393	2,783
ESPP to purchase common shares	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'
Potential dilutive securities (in shares)	0	307

Concentration_of_Credit_Risk_a2

Concentration of Credit Risk and Significant Customers - (Details)

3 Months Ended

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Jun. 30, 2014

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Jun. 30, 2014

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Jun. 30, 2014

Minimum

Maximum

Customer A

Customer A

Customer A

Customer A

Customer B

Customer B

Customer B

Customer B

Customer C

Customer C

Customer C

Customer C

Sales Revenue, Goods, Net

Sales Revenue, Goods, Net

Accounts Receivable

Accounts Receivable

Sales Revenue, Goods, Net

Sales Revenue, Goods, Net

Accounts Receivable

Accounts Receivable

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

Concentration Risk

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Terms of credit sales, (in days)

'30 days

'60 days

'

'

'

'

'

'

'

'

'

'

'

'

Customers greater than 10% of total

'

'

24.10%

20.60%

32.60%

23.10%

39.60%

44.30%

15.60%

30.50%

12.90%

11.80%

24.70%

17.40%

Balance_Sheet_Components_Accou

Balance Sheet Components - Accounts receivable (Details) (USD $)	Sep. 30, 2014	Jun. 30, 2014
In Thousands, unless otherwise specified
Balance Sheet Related Disclosures [Abstract]	'	'
Accounts receivable	$50,657	$51,128
Less: allowance for price adjustments	-15,561	-14,563
Less: allowance for doubtful accounts	-30	-30
Accounts receivable, net	$35,066	$36,535

Balance_Sheet_Components_Inven

Balance Sheet Components - Inventories (Details) (USD $)	Sep. 30, 2014	Jun. 30, 2014
In Thousands, unless otherwise specified
Balance Sheet Related Disclosures [Abstract]	'	'
Raw materials	$18,539	$18,996
Work in-process	38,642	36,003
Finished goods	11,229	11,561
Inventory, net	$68,410	$66,560

Balance_Sheet_Components_Prope

Balance Sheet Components - Property, plant, and equipment (Details) (USD $)	Sep. 30, 2014	Jun. 30, 2014
In Thousands, unless otherwise specified
Property, Plant and Equipment [Line Items]	'	'
Property, plant, and equipment excluding equipment and construction In progress, gross	$230,403	$227,012
Less accumulated depreciation	-121,543	-114,658
Property, plant and equipment excluding equipment and construction in progress, net	108,860	112,354
Equipment and construction in progress	12,039	10,900
Property, plant and equipment, net	120,899	123,254
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	4,241	4,106
Manufacturing machinery and equipment	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, plant, and equipment excluding equipment and construction In progress, gross	163,854	161,354
Equipment and tooling	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, plant, and equipment excluding equipment and construction In progress, gross	10,644	10,486
Computer equipment and software	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, plant, and equipment excluding equipment and construction In progress, gross	19,689	19,319
Office furniture and equipment	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, plant, and equipment excluding equipment and construction In progress, gross	1,639	1,643
Leasehold improvements	'	'
Property, Plant and Equipment [Line Items]	'	'
Property, plant, and equipment excluding equipment and construction In progress, gross	$25,386	$25,154

Balance_Sheet_Components_Other

Balance Sheet Components - Other long term assets (Details) (USD $)	Sep. 30, 2014	Jun. 30, 2014
In Thousands, unless otherwise specified
Balance Sheet Related Disclosures [Abstract]	'	'
Prepayments for property and equipment	$1,782	$1,435
Investment in a privately held company	100	100
Office leases deposits	401	428
Other long-term assets	$2,283	$1,963

Balance_Sheet_Components_Accru

Balance Sheet Components - Accrued liabilities (Details) (USD $)	Sep. 30, 2014	Jun. 30, 2014	Sep. 30, 2013	Jun. 30, 2013
In Thousands, unless otherwise specified
Balance Sheet Related Disclosures [Abstract]	'	'	'	'
Accrued compensation and benefit	$3,897	$4,879	'	'
Accrued vacation	1,973	1,777	'	'
Accrued bonuses	1,947	1,873	'	'
Warranty accrual	1,230	1,346	1,361	1,428
Stock rotation accrual	1,607	1,645	1,597	1,572
Accrued professional fees	1,175	1,001	'	'
ESPP payable	810	323	'	'
Customer deposits	102	104	'	'
Accrued inventory	450	590	'	'
Accrued facilities related expenses	1,570	1,353	'	'
Other accrued expenses	2,516	2,485	'	'
Accrued liabilities	$17,277	$17,376	'	'

Balance_Sheet_Components_Produ

Balance Sheet Components - Product Warranty Accrual (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Movement in Standard and Extended Product Warranty, Increase (Decrease) [Roll Forward]	'	'
Beginning balance	$1,346	$1,428
Additions	530	285
Utilization	-646	-352
Ending balance	$1,230	$1,361

Balance_Sheet_Components_Stock

Balance Sheet Components - Stock Rotation Accrual (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Stock Rotation Accrual Increae (Decrease) [Roll Forward]	'	'
Beginning balance	$1,645	$1,572
Additions	1,294	1,346
Utilization	-1,332	-1,321
Ending balance	$1,607	$1,597

Balance_Sheet_Components_Other1

Balance Sheet Components - Other Long Term Liability (Details) (USD $)	Sep. 30, 2014	Jun. 30, 2014
In Thousands, unless otherwise specified
Balance Sheet Related Disclosures [Abstract]	'	'
Deferred rent	$1,096	$1,143
Customer deposit	3	0
Other long term liabilities	$1,099	$1,143

Debt_Details

Debt - (Details) (USD $)

3 Months Ended

0 Months Ended

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Jun. 30, 2014

11-May-12

Sep. 30, 2014

Jul. 17, 2012

11-May-12

11-May-12

11-May-12

11-May-12

11-May-12

11-May-12

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

London Interbank Offered Rate (LIBOR) [Member]

London Interbank Offered Rate (LIBOR) [Member]

Federal Funds Rate [Member]

Eurodollar [Member]

Eurodollar [Member]

Eurodollar [Member]

Notes Payable to Banks

Notes Payable to Banks

Notes Payable to Banks

Loans Payable

Loans Payable

Minimum

Maximum

Minimum

Maximum

subsidiary

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

Line of Credit Facility, Amount Outstanding

'

'

$0

'

'

'

'

'

'

'

'

'

'

Loan, principal amount

'

'

'

'

20,000,000

'

250,000

'

'

'

'

'

'

Line of Credit Facility, Maximum Borrowing Capacity

'

'

'

'

10,000,000

'

'

'

'

'

'

'

'

Debt instrument, basis spread on variable rate

'

'

'

'

'

'

'

1.00%

1.75%

0.50%

1.00%

-0.50%

0.25%

Outstanding balance of loan

'

'

7,900,000

13,600,000

'

0

'

'

'

'

'

'

'

Number of subsidiaries securing obligations under loan agreement

'

'

2

'

'

'

'

'

'

'

'

'

'

Interest rate on loan

'

'

'

'

'

'

5.00%

'

'

'

'

'

'

Forgiveness of loan

($250,000)

$0

'

'

'

'

'

'

'

'

'

'

'

Shareholders_Equity_and_Shareb2

Shareholders' Equity and Share-based Compensation - Shares Repurchase (Details) (USD $)	0 Months Ended		3 Months Ended	47 Months Ended
	8-May-14	Oct. 22, 2010	Sep. 30, 2014	Sep. 30, 2014
Class of Stock [Line Items]	'	'	'	'
Share repurchase program, authorized amount (USD in Millions)	'	$25,000,000	'	'
Shares Repurchase Program Remaining Balance	22,700,000	'	'	'
Treasury stock acquired, shares repurchased (in shares)	'	'	0	361,364
Treasury Stock, Value, Acquired, Cost Method	'	'	'	$3,200,000
Treasury stock acquired, average price per share (in dollars per share)	'	'	'	$8.82
Treasury Stock, Shares, Retired	'	'	'	0
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures (in shares)	'	'	'	21,650
Treasury Stock Reissued, Average Price Per Share	'	'	'	$3
Treasury Stock Reissued	'	'	'	'
Class of Stock [Line Items]	'	'	'	'
Treasury stock acquired, average price per share (in dollars per share)	'	'	'	$13.81

Shareholders_Equity_and_Shareb3

Shareholders' Equity and Share-based Compensation - Share-based Compensation (Details) (USD $)	3 Months Ended	47 Months Ended
	Sep. 30, 2014	Sep. 30, 2014	Jun. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Treasury stock acquired, shares repurchased (in shares)	0	361,364	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]	'	'	'
Outstanding at June 30, 2014 (in shares)	3,238,784	'	'
Granted (in shares)	10,000	'	'
Exercised (in shares)	-128,231	'	'
Canceled or forfeited (in shares)	-17,484	'	'
Outstanding at September 30, 2014 (in shares)	3,103,069	3,103,069	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]	'	'	'
Outstanding at June 30, 2014 (in dollars per share)	$10.28	'	'
Granted (in dollars per share)	$9.07	'	'
Exercised (in dollars per share)	$6.69	'	'
Canceled or forfeited (in dollars per share)	$15.87	'	'
Outstanding at September 30, 2014 (in dollars per share)	$10.40	$10.40	'
Options Outstanding Aggregate Intrinsic Value	$3,118,240	$3,118,240	$3,258,607
Options Exercised Aggregate Intrinsic Value	$392,484	'	'
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	0.40%	'	'
Stock Options [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Volatility Rate	43.50%	'	'
Risk Free Interest Rate	1.70%	'	'
Expected Term	'5 years 6 months	'	'
Expected Dividend Rate	0.00%	'	'

Shareholders_Equity_and_Shareb4

Shareholders' Equity and Share-based Compensation - Stock Options Outstanding and Exercisable (Details) (USD $)	3 Months Ended
	Sep. 30, 2014	Jun. 30, 2014
Share-based Compensation [Abstract]	'	'
Options, Number Outstanding (in shares)	3,103,069	3,238,784
Options, Weighted-Average Remaining Contractual Life (in years)	'5 years 8 months 5 days	'
Options, Weighted-Average Exercise Price (in dollars per share)	$10.40	$10.28
Options, Number Exercisable (in shares)	2,115,149	'
Options, Weighted-Average Exercise Price (in dollars per share)	$11.26	'
Options vested and expected to vest, Number Outstanding (in shares)	3,005,766	'
Options vested and expected to vest, Weighted Average Remaining Contractual Life (in years)	'5 years 6 months 26 days	'
Options vested and expected to vest, Weighted Average Exercise Price (in dollars per share)	$10.48	'

Shareholders_Equity_and_Shareb5

Shareholders' Equity and Share-based Compensation - Restricted Stock Activity (Details) (USD $)	3 Months Ended
	Sep. 30, 2014	Jun. 30, 2014
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 4 months 24 days	'
Restricted Stock	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]	'	'
Nonvested	656,374	'
Granted	25,500	'
Vested	-19,674	'
Forfeited	-29,950	'
Nonvested	632,250	656,374
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]	'	'
Nonvested	$8.40	'
Granted	$9.48	'
Vested	$8.92	'
Forfeited	$8.41	'
Nonvested	$8.43	$8.40
Weighted Average Remaining Recognition Period (Years)	'1 year 7 months 10 days	'1 year 9 months 7 days
RSUs Nonvested Aggregate Intrinsic Value	$5,943,150	$6,084,587
RSUs vested and expected to vest, Outstanding (in shares)	557,582	'
RSUs vested and expected to vest, Weighted Average Remaining Recognition Period (in years)	'1 year 6 months 7 days	'
RSUs vested and expected to vest, Aggregate Intrinsic Value	$5,241,267	'

Shareholders_Equity_and_Shareb6

Shareholders' Equity and Share-based Compensation - Share-based Compensation Expenses (Details) (USD $)	3 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'
Allocated share-based compensation expense	$1,102,000	$1,209,000
Unrecognized compensation expense	4,700,000	'
Recognition period of share-based compensation expense (in years)	'1 year 4 months 24 days	'
Cost of goods sold	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'
Allocated share-based compensation expense	154,000	196,000
Research and development	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'
Allocated share-based compensation expense	206,000	295,000
Selling, general and administrative	'	'
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]	'	'
Allocated share-based compensation expense	$742,000	$718,000

Income_Taxes_Narrative_Details

Income Taxes - Narrative (Details) (USD $)	3 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'	'
Income tax expense	$1,171,000	$1,002,000
Estimated effective income tax rate	67.50%	76.50%
Unrecognized tax benefits	6,800,000	'
Unrecognized Tax Benefit, Amount Netted Against Deferred Tax Assets	$4,800,000	'

Segment_and_Geographic_Informa2

Segment and Geographic Information - Revenue by Location and Product Type (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Revenue	$88,217	$84,121
Power discrete	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Revenue	64,891	65,145
Power IC	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Revenue	19,156	13,612
Packaging and testing services	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Revenue	4,170	5,364
Hong Kong	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Revenue	75,247	71,256
China	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Revenue	10,957	10,892
South Korea	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Revenue	639	797
United States	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Revenue	683	473
Other Countries	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Revenue	$691	$703

Segment_and_Geographic_Informa3

Segment and Geographic Information - Long-lived Assets (Details) (USD $)	Sep. 30, 2014	Jun. 30, 2014
In Thousands, unless otherwise specified
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Property, plant and equipment, net	$120,899	$123,254
China	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Property, plant and equipment, net	79,262	80,736
United States	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Property, plant and equipment, net	41,245	42,106
Other Countries	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'
Property, plant and equipment, net	$392	$412

Segment_and_Geographic_Informa4

Segment and Geographic Information - Narratives (Details)	3 Months Ended
	Sep. 30, 2014
	Segment
Segment Reporting [Abstract]	'
Number of operating segments	1
Number of reportable segments	1

Commitments_and_Contingencies_

Commitments and Contingencies - Purchase Commitments (Details) (USD $)	Sep. 30, 2014	Jun. 30, 2014
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	$20.60	$34.50
Property and equipment purchase commitments	'	'
Purchase Commitment, Excluding Long-term Committment [Line Items]	'	'
Purchase commitment, amount	$2.50	$4.60

Commitments_and_Contingencies_1

Commitments and Contingencies - Guarantees (Details) (Indemnification Agreement, USD $)	Sep. 30, 2014
Indemnification Agreement	'
Loss Contingencies [Line Items]	'
Indemnifications accrual	$0