OmniVision (OVTI) 10-Q 6 Mar 15 2015 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Jan. 31, 2015	Mar. 02, 2015
Document and Entity Information
Entity Registrant Name	OMNIVISION TECHNOLOGIES INC
Entity Central Index Key	1106851
Document Type	10-Q
Document Period End Date	31-Jan-15
Amendment Flag	FALSE
Current Fiscal Year End Date	-26
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		58,106,421
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q3

CONDENSED_CONSOLIDATED_BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (USD $)	Jan. 31, 2015	Apr. 30, 2014
Current assets:
Cash and cash equivalents	$308,161,000	$297,952,000
Short-term investments	204,626,000	152,993,000
Accounts receivable, net	141,706,000	172,472,000
Inventories	366,379,000	270,935,000
Deferred income taxes	4,553,000	4,973,000
Prepaid expenses and other current assets	6,473,000	6,576,000
Recoverable insurance proceeds	12,500,000
Total current assets	1,044,398,000	905,901,000
Property, plant and equipment, net	148,516,000	153,792,000
Long-term investments	145,310,000	154,409,000
Goodwill	10,227,000	10,227,000
Intangibles, net	55,760,000	66,217,000
Other long-term assets	25,194,000	32,529,000
Total assets	1,429,405,000	1,323,075,000
Current liabilities:
Accounts payable	146,905,000	142,012,000
Accrued expenses and other current liabilities	28,583,000	31,959,000
Litigation settlement accrual	12,500,000
Income taxes payable	6,081,000	2,316,000
Deferred revenues, less cost of revenues	19,709,000	25,783,000
Current portion of long-term debt	7,071,000	3,802,000
Total current liabilities	220,849,000	205,872,000
Long-term liabilities:
Long-term income taxes payable	51,127,000	86,498,000
Non-current portion of long-term debt	25,128,000	32,030,000
Other long-term liabilities	21,853,000	11,818,000
Total long-term liabilities	98,108,000	130,346,000
Total liabilities	318,957,000	336,218,000
Commitments and contingencies (Note 13)
Stockholders' equity:
Common stock, $0.001 par value; 100,000 shares authorized; 78,655 shares issued and 58,056 outstanding at January 31, 2015 and 76,681 shares issued and 56,082 outstanding at April 30, 2014, respectively	79,000	77,000
Additional paid-in capital	700,668,000	664,602,000
Accumulated other comprehensive income	2,507,000	2,378,000
Treasury stock, 20,599 at January 31, 2015 and April 30, 2014, respectively	-278,683,000	-278,683,000
Retained earnings	685,877,000	598,483,000
Total stockholders' equity	1,110,448,000	986,857,000
Total liabilities and stockholders' equity	$1,429,405,000	$1,323,075,000

CONDENSED_CONSOLIDATED_BALANCE1

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Jan. 31, 2015	Apr. 30, 2014
In Thousands, except Per Share data, unless otherwise specified
CONDENSED CONSOLIDATED BALANCE SHEETS
Common stock, par value (in dollars per share)	$0.00	$0.00
Common stock, shares authorized	100,000	100,000
Common stock, shares issued	78,655	76,681
Common stock, shares outstanding	58,056	56,082
Treasury stock, shares	20,599	20,599

CONDENSED_CONSOLIDATED_STATEME

CONDENSED CONSOLIDATED STATEMENTS OF INCOME (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2015	Jan. 31, 2014
CONDENSED CONSOLIDATED STATEMENTS OF INCOME
Revenues	$292,341	$352,023	$1,092,922	$1,122,960
Cost of revenues	227,759	282,891	853,423	913,801
Gross profit	64,582	69,132	239,499	209,159
Operating expenses:
Research, development and related	33,190	30,936	102,108	87,761
Selling, general and administrative	19,465	18,028	58,904	54,684
Amortization of acquired patent portfolio	2,321	2,321	6,964	6,964
Total operating expenses	54,976	51,285	167,976	149,409
Income from operations	9,606	17,847	71,523	59,750
Equity in earnings of investee	1,279	837	3,248	3,264
Interest expense, net	-404	-466	-1,256	-1,542
Other income, net	324	24,038	1,588	25,206
Income before income taxes	10,805	42,256	75,103	86,678
Provision for (benefit from) income taxes	-3,218	11,696	-12,291	6,754
Net income	$14,023	$30,560	$87,394	$79,924
Net income per share:
Basic (in dollars per share)	$0.24	$0.55	$1.52	$1.44
Diluted (in dollars per share)	$0.23	$0.54	$1.48	$1.42
Shares used in computing net income per share:
Basic (in shares)	57,948	55,913	57,383	55,369
Diluted (in shares)	60,134	56,186	59,238	56,472

CONDENSED_CONSOLIDATED_STATEME1

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2015	Jan. 31, 2014
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Net income	$14,023	$30,560	$87,394	$79,924
Other comprehensive income (loss), net of tax:
Translation gains (losses)	131	-27	107	215
Reclassification adjustments for (gains) on sale of WLCSP included in net income, net of tax		-665		-665
Translation gains (losses)	131	-692	107	-450
Unrealized gains (losses) on available-for-sale securities	24	-15	23	355
Reclassification adjustments for gains on available-for-sale securities included in net income			-1	-1,288
Unrealized gains (losses) on available-for-sale securities	24	-15	22	-933
Other comprehensive income (loss)	155	-707	129	-1,383
Comprehensive income	$14,178	$29,853	$87,523	$78,541

CONDENSED_CONSOLIDATED_STATEME2

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Jan. 31, 2014
Cash flows from operating activities:
Net income	$87,394	$79,924
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	26,225	23,751
Change in fair value of interest rate swap	-639	-933
Stock-based compensation	25,816	25,912
Tax effect from stock-based compensation	2,458	3,926
Gain on equity investments, net	-7,461	-17,865
Write-down of inventories	30,389	25,978
Excess tax benefits from stock-based compensation	-2,458	-3,311
Gain associated with WLCSP IPO		-23,802
Gain on sale of investment in Tong Hsing		-1,990
(Gain) loss on disposal of property, plant and equipment	4	-154
Changes in assets and liabilities:
Accounts receivable, net	30,766	31,811
Inventories	-126,254	66,350
Deferred income taxes	-5,059	8,143
Prepaid expenses and other assets	12,661	1,492
Accounts payable	6,512	-38,705
Accrued expenses and other liabilities	6,059	-1,564
Income taxes payable	-18,349	-8,611
Deferred revenues, less cost of revenues	-6,091	5,144
Net cash provided by operating activities	61,973	175,496
Cash flows from investing activities:
Purchases of short-term investments	-261,489	-126,979
Proceeds from sales or maturities of short-term investments	207,847	64,327
Purchases of property, plant and equipment, net of sales	-9,717	-13,154
Proceeds from sale of investment in Tong Hsing		6,224
Net cash used in investing activities	-63,359	-69,582
Cash flows from financing activities:
Repayment of long-term borrowings	-3,674	-3,691
Excess tax benefits from stock-based compensation	2,458	3,311
Proceeds from exercise of stock options and employee stock purchase plan	12,837	13,206
Net cash provided by financing activities	11,621	12,826
Effect of exchange rate changes on cash and cash equivalents	-26	16
Net increase in cash and cash equivalents	10,209	118,756
Cash and cash equivalents at beginning of period	297,952	190,171
Cash and cash equivalents at end of period	308,161	308,927
Supplemental cash flow information:
Taxes paid	8,615	3,422
Interest paid	1,654	1,826
Supplemental schedule of non-cash investing and financing activities:
Additions to intangible assets included in accruals		21,906
Sale of WLCSP shares		15,066
Additions to property, plant and equipment included in accounts payable and accrued expenses and other current liabilities	2,622	2,786
Write-off of employee stock-based compensation-related deferred tax assets	$858	$722

Basis_of_Presentation

Basis of Presentation	9 Months Ended
	Jan. 31, 2015
Basis of Presentation
Basis of Presentation	Note 1 — Basis of Presentation
	Overview
	The accompanying interim unaudited condensed consolidated financial statements as of January 31, 2015 and April 30, 2014 and for the three and nine months ended January 31, 2015 and 2014 have been prepared by OmniVision Technologies, Inc., and its subsidiaries (“OmniVision” or the “Company”) in accordance with the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”). The amounts as of April 30, 2014 are derived from the Company’s audited annual financial statements. Certain information and footnote disclosures normally included in financial statements prepared in accordance with generally accepted accounting principles have been condensed or omitted in accordance with SEC rules and regulations. In the opinion of management, the accompanying unaudited condensed consolidated financial statements reflect all adjustments, consisting only of normal recurring adjustments, necessary to state fairly the financial position of the Company and its results of operations and cash flows as of and for the periods presented. These condensed consolidated financial statements should be read in conjunction with the audited annual financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the fiscal year ended April 30, 2014 (the “Form 10-K”).
	Use of Estimates
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America (“GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. The Company bases its estimates and judgments on its historical experience, knowledge of current conditions and beliefs of what could occur in the future considering available information. Actual results could differ from these estimates.

Recent_Accounting_Pronouncemen

Recent Accounting Pronouncements	9 Months Ended
	Jan. 31, 2015
Recent Accounting Pronouncements
Recent Accounting Pronouncements	Note 2 — Recent Accounting Pronouncements
	In April 2014, the Financial Accounting Standards Board (“FASB”) revised the authoritative guidance on reporting discontinued operations. The revised guidance specifies that a disposal of a component of an entity or a group of components of an entity is required to be reported in a discontinued operation if the disposal represents a strategic shift that has, or will have a major effect on an entity’s operations and financial results. The guidance also changes the requirements for reporting discontinued operations which requires additional disclosures for discontinued operations and new disclosures for individually material disposal transactions that do not meet the definition of a discontinued operation. The guidance is effective for the Company beginning in the first quarter of fiscal 2016. The Company is currently evaluating the impact this guidance may have on its financial position, results of operations and cash flows.
	In May 2014, the FASB issued new authoritative guidance for revenue recognition. The new revenue recognition guidance provides a comprehensive framework to address revenue recognition issues for all contracts with customers, and supersedes most previously-issued industry-specific guidance. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. To achieve that core principle and apply the new guidance, entities will follow a five-step approach: Step 1) identify the contracts with the customer; Step 2) identify the separate performance obligations in the contract; Step 3) determine the transaction price; Step 4) allocate the transaction price to separate performance obligations; and Step 5) recognize revenue when, or as, each performance obligation is satisfied. The new guidance is required to be applied retrospectively to each prior reporting period presented, or retrospectively with the cumulative effect of initially applying it recognized at the date of initial application. The guidance is effective for the Company beginning in the first quarter of fiscal 2018. The Company has not yet selected the transition method, and is currently evaluating the impact this guidance may have on its financial position, results of operations and cash flows.
	In August 2014, the FASB issued new authoritative guidance related to the disclosures around going concern. The new guidance specifies management’s responsibility to evaluate whether there is substantial doubt about an entity’s ability to continue as a going concern and to provide related footnote disclosures. The new guidance is effective for the Company beginning in the first quarter of fiscal 2018. Early adoption is permitted. The Company does not expect the adoption of this guidance to have any material effect on its financial position, results of operations and cash flows.
	In January 2015, the FASB revised the authoritative guidance on reporting extraordinary items by eliminating such concept from GAAP. Previously, if an event or transaction meets the criteria for extraordinary classification, an entity is required to segregate the extraordinary item from the results of ordinary operations and show the item separately in the income statement, net of tax. The guidance is effective for the Company beginning in the first quarter of fiscal 2017. The Company does not expect the adoption of this guidance to have any material effect on its financial position, results of operations and cash flows.

ShortTerm_Investments

Short-Term Investments	9 Months Ended
	Jan. 31, 2015
Short-Term Investments
Short-Term Investments	Note 3 — Short-Term Investments
	Available-for-sale securities as of the dates presented were as follows (in thousands):
		As of January 31, 2015
		Amortized		Gross		Gross			Fair
				Unrealized		Unrealized
		Cost		Gains		Losses			Value
	Municipal bonds	$	9,205	$	—	$	(3	)	$	9,202
	U.S. government debt securities with maturities less than one year	26,652		4					26,656
	Corporate debt securities/commercial paper	168,778		13		(23		)	168,768
		$	204,635	$	17	$	(26	)	$	204,626
	Contractual maturity dates, less than one year								$	201,569
	Contractual maturity dates, one to two years								3,057
									$	204,626
		As of April 30, 2014
		Amortized		Gross		Gross			Fair
				Unrealized		Unrealized
		Cost		Gains		Losses			Value
	Municipal bonds	$	6,168	$	1	$	(2	)	$	6,167
	Corporate debt securities/commercial paper	146,866		6		(46		)	146,826
		$	153,034	$	7	$	(48	)	$	152,993
	Contractual maturity dates, less than one year								$	142,758
	Contractual maturity dates, one to two years								10,235
									$	152,993

Supplemental_Balance_Sheet_Acc

Supplemental Balance Sheet Account Information (in thousands)	9 Months Ended
	Jan. 31, 2015
Supplemental Balance Sheet Account Information (in thousands)
Supplemental Balance Sheet Account Information (in thousands)	Note 4 — Supplemental Balance Sheet Account Information (in thousands)
		January 31,			April 30,
		2015			2014
	Cash and cash equivalents:
	Cash	$	231,640		$	195,141
	Money market funds, commercial paper and U.S. government bonds	76,521			102,811
		$	308,161		$	297,952
	Accounts receivable, net:
	Accounts receivable	$	144,758		$	176,576
	Less:  Allowance for doubtful accounts	(886		)	(998		)
	Allowance for sales returns	(2,166		)	(3,106		)
		$	141,706		$	172,472
	Inventories:
	Work in progress	$	173,686		$	107,621
	Finished goods	192,693			163,314
		$	366,379		$	270,935
	Prepaid expenses and other current assets:
	Prepaid expenses	$	5,109		$	4,285
	Deposits and other	331			1,284
	Interest receivable	1,033			1,007
		$	6,473		$	6,576
	Property, plant and equipment, net:
	Land	$	13,000		$	13,000
	Buildings	82,623			82,547
	Buildings/leasehold improvements	29,318			29,123
	Machinery and equipment	120,046			119,762
	Furniture and fixtures	5,030			5,002
	Software	8,853			8,774
	Construction in progress	1,998			2,894
		260,868			261,102
	Less: Accumulated depreciation and amortization	(112,352		)	(107,310		)
		$	148,516		$	153,792
	Other long-term assets:
	Deferred tax assets — non-current	$	1,096		$	528
	Land-use rights	2,137			2,180
	Other long-term assets	21,961			29,821
		$	25,194		$	32,529
	Accrued expenses and other current liabilities:
	Deferred tax liabilities — current	$	144		$	144
	Employee compensation	12,677			15,176
	Third party commissions	511			380
	Professional services	2,574			2,270
	Noncancelable purchase commitments	729			647
	Rebates	1,896			1,511
	Other	10,052			11,831
		$	28,583		$	31,959
	Other long-term liabilities:
	Interest rate swap	$	2,341		$	2,980
	Deferred tax liabilities — non-current	12,992			3,731
	Other	6,520			5,107
		$	21,853		$	11,818

Longterm_Investments

Long-term Investments	9 Months Ended
	Jan. 31, 2015
Long-term Investments
Long-term Investments	Note 5 — Long-term Investments
	Long-term investments as of the dates indicated consisted of the following (in thousands):
		January 31,			April 30,
		2015			2014
	VisEra	$	103,402		$	115,943
	WLCSP	37,247			33,805
	XinTec	4,661			4,661
	Total	$	145,310		$	154,409
	VisEra Technologies Company, Ltd.
	In October 2003, the Company and Taiwan Semiconductor Manufacturing Company Limited (“TSMC”) entered into an agreement to form VisEra Technologies Company, Ltd. (“VisEra”), a joint venture in Taiwan, for the purposes of providing certain manufacturing and automated final testing services related to complementary metal oxide semiconductor (“CMOS”) image sensors. In August 2005, under an amendment to the original 2003 joint-venture agreement, the Company and TSMC formed VisEra Holding Company (“VisEra Cayman”), a company incorporated in the Cayman Islands, and VisEra became a subsidiary of VisEra Cayman. The Company and TSMC have equal interests in VisEra Cayman. As of January 31, 2015, the Company owned 49.1% of VisEra Cayman.
	In June 2011, the Company entered into an agreement with VisEra to acquire from VisEra its CameraCubeChip production operations. The acquisition of the production operations was completed in October 2011, and the Company accounted for the transaction as a business combination. Under the terms of the agreement, the closing consideration was $42.9 million in cash. In April 2014, due to the lack of commercial viability for certain milestone deliverables, the Company agreed with VisEra to reduce the final installment of cash consideration from $9.0 million to $4.5 million. Consequently, the Company recorded a $3.1 million post-acquisition gain in “Benefit from acquisition of production operations from VisEra,” representing the $4.5 million reduction in the final installment payment, net of a $1.4 million equity method elimination for the corresponding receivable write-off recorded by VisEra. The Company paid the final $4.5 million to VisEra in April 2014.
	The Company received the following dividend payments from VisEra during the periods presented (in thousands):
		Nine Months Ended
		January 31,
		2015			2014
	Dividend payments received from VisEra	$	17,101		$	—
	The Company accounts for its investment in VisEra under the equity method. The following table presents equity income before elimination of unrealized intercompany profits and the equity income recorded by the Company for the periods indicated in “Cost of revenues,” consisting of its portion of the net income recorded by VisEra during the periods presented after the elimination of unrealized intercompany profits (in thousands).
		Three Months Ended						Nine Months Ended
		January 31,						January 31,
		2015			2014			2015			2014
	Equity income (losses)	$	680		$	(331	)	$	4,560		$	10,079
	Net effect on Cost of revenues, after the elimination of unrealized intercompany profits	$	(81	)	$	4,220		$	4,213		$	16,378
	China WLCSP Limited
	China WLCSP Limited (“WLCSP”) is in the business of designing, manufacturing, packaging and selling certain wafer level chip scale packaging related services. In May 2007, the Company acquired 4,500,000 units of WLCSP’s equity interests, or 20.0% of WLCSP’s registered capital on a fully-diluted basis, for an aggregate purchase amount of $9.0 million. In April 2010, WLCSP raised additional capital and reduced the Company’s ownership percentage to 19.7%. In May 2010, WLCSP converted all of its owners’ equity into share capital. The pro rata interests of all shareholders remained the same after the conversion and no income was distributed. After the conversion, WLCSP had 180.0 million shares outstanding, and the Company owned 35.4 million shares. In September 2010, WLCSP issued an additional 9.5 million shares to other parties and reduced the Company’s ownership percentage to 18.7%.
	The Company has a seat on the WLCSP Board of Directors. With the determination that the Company has maintained significant influence over the operations of WLCSP, the Company accounts for its investment in WLCSP under the equity method.
	In December 2013, WLCSP filed with the China Securities Regulatory Commission (“CSRC”) a registration statement for an initial public offering (“IPO”). The registration statement was approved by the CSRC in January 2014, and the IPO price was approximately $3.14 per share. As part of the IPO, WLCSP issued 37.2 million new shares and increased the total shares outstanding to 226.7 million shares. The Company also participated in the IPO as selling shareholder and sold 5.1 million shares, reducing the total number of shares owned by the Company to 30.3 million shares.
	The issuance price of $3.14 for the 37.2 million new shares was higher than the Company’s average per share carrying value for WLCSP. Consequently, the Company recognized a non-cash change-in-interest gain of approximately $14.1 million. In addition, with the sale of 5.1 million shares during the IPO, the Company received net cash proceeds of approximately $15.1 million, and recognized approximately $9.7 million as gain on the sale. The change-in-interest gain and the realized gain from the share sale, totaling approximately $23.8 million, was recorded in “Other income, net” for the three months ended January 31, 2014.
	The foreign exchange effects on WLCSP’s net assets are recorded as part of the Company’s cumulative translation adjustment in “Accumulated other comprehensive income.” The total gain of $23.8 million from WLCSP’s IPO included a pro rata release of approximately $1.0 million of the cumulative translation adjustment from “Accumulated other comprehensive income.”
	As of January 31, 2015, the 30.3 million WLCSP shares owned by the Company represented an ownership percentage of 13.3%. The Company received the following dividend payments from WLCSP during the periods presented (in thousands):
		Nine Months Ended
		January 31,
		2015			2014
	Dividend payments received from WLCSP	$	726		$	830
	The Company accounts for its investment in WLCSP under the equity method. The following table presents equity income recorded by the Company for the periods indicated in “Equity in earnings of investee,” consisting of its portion of the net income recorded by WLCSP during the periods presented, and equity method investment adjustments (in thousands). In the fourth quarter of fiscal 2014, to comply with China’s securities laws after WLCSP’s IPO, the Company introduced a one-month lag in its equity method of accounting for WLCSP. As such, for the three and nine months ended January 31, 2015, the Company included its share of WLCSP’s earnings from October 1, 2014 to December 31, 2014 and from April 1, 2014 to December 31, 2014, respectively. For the three months ended January 31, 2014, the Company’s share of WLCSP’s net income was based solely on the Company’s own best estimates. This was due to WLCSP scheduling the release of their December 31, 2013 financial results in April 2014, after their January 2014 IPO. Under China’s securities law, the Company is not able to disclose any periodic financial information which may otherwise be available to the Company in its capacity as a representative on WLCSP’s Board of Directors, until such information was publicly released in China.
		Three Months Ended						Nine Months Ended
		January 31,						January 31,
		2015			2014			2015			2014
	Equity income	$	1,279		$	837		$	3,248		$	3,264
	XinTec, Inc.
	XinTec, Inc. (“XinTec”) is a Taiwan-based supplier of chip scale packaging services. The Company first made investments in XinTec in April 2003, for $2.8 million. As of January 31, 2015, the Company’s direct ownership percentage in XinTec was 4.12%. Separately, VisEra Cayman owns a 15.63% interest in XinTec. Consequently, the Company’s beneficial ownership percentage in XinTec was approximately 11.80%. The Company accounts for XinTec as a cost method investment.
	Tong Hsing Electronic Industries, Limited
	Tong Hsing Electronic Industries, Limited (“Tong Hsing”) is a Taiwan-based public company principally engaged in the development and production of microelectronic packaging technologies. In December 2009, the Company obtained 0.8% of the outstanding shares of common stock of Tong Hsing, or 996,250 shares, when Tong Hsing acquired ImPac Technology Co., Ltd. (“ImPac”) in a stock-for-stock exchange. Prior to the exchange, the Company owned 25.7% of ImPac. In June 2010 and June 2011, the Company participated in Tong Hsing’s secondary offerings and purchased 95,570 and 115,481 shares, respectively, for corresponding amounts of approximately $282,000 and $421,000. In October 2013, the Company sold its entire investment in Tong Hsing, which amounted to an ownership percentage in Tong Hsing of approximately 0.7%. With the sale, the Company recorded a gain of approximately $2.0 million in “Other income, net” for the three months ended October 31, 2013.
	Phostek, Inc.
	Phostek, Inc. (“Phostek”) is a privately held company that develops and manufactures light emitting diodes in Taiwan. The Company made an investment in Phostek in February 2012, for a total of $2.0 million in cash, and accounted for this investment using the cost method. In July 2013, based on a combination of factors, including Phostek’s accumulated losses and its decision to not pursue any additional fundings to support its original business plans, the Company concluded that the investment in Phostek should be impaired in its entirety. Consequently, the Company recorded an impairment charge of $2.0 million in “Other income, net” for the three months ended July 31, 2013.
	The following table presents the summary financial information of VisEra and WLCSP, as derived from their financial statements for the periods indicated. Each of the investee’s statement was prepared under US GAAP (in thousands).
	As mentioned above, with WLCSP’s IPO in January 2014 and disclosure restrictions applicable then under China’s securities law, the Company was previously unable to disclose summarized financial information of WLCSP for the three and nine months ended January 31, 2014. Disclosure of such historical information in the current period would also not be consistent with any subsequent public disclosures from WLCSP. The summary financial information of WLCSP for the three and nine months ended December 31, 2013 are presented below as prior year comparatives. This information was included as part of the Company’s own best estimate of its share of WLCSP’s net income for the three months ended January 31, 2014.
	VisEra Technologies Company, Ltd.
		Three Months Ended						Nine Months Ended
		January 31,						January 31,
		2015			2014			2015			2014
	Operating data:
	Revenues	$	28,998		$	24,236		$	86,002		$	103,500
	Gross profit	5,962			13,147			21,240			46,866
	Income from operations	3,746			10,567			14,328			38,953
	Net income (loss)	$	(165	)	$	8,588		$	8,574		$	33,328
	China WLCSP Limited
		Three Months Ended							Nine Months Ended
		December 31,							December 31,
		2014			2013				2014			2013
	Operating data:
	Revenues	$	32,022		$	20,111			$	78,082		$	58,651
	Gross profit	14,064			11,522				40,428			32,176
	Income from operations	7,125			6,415				21,928			21,712
	Net income	$	9,589		$		6,474		$	24,333		$		18,736
The Company’s share of undistributed earnings of investees accounted for by the equity method as of the dates indicated were as follows (in thousands):
	January 31,			April 30,
	2015			2014
Undistributed earnings of investees	$	56,431		$	66,772

Goodwill_and_Intangible_Assets

Goodwill and Intangible Assets	9 Months Ended
	Jan. 31, 2015
Goodwill and Intangible Assets
Goodwill and Intangible Assets	Note 6 — Goodwill and Intangible Assets
	Goodwill
	The following table summarizes the change to the carrying value of the Company’s goodwill during the periods presented (in thousands):
		Nine Months Ended
		January 31,
		2015		2014
	Beginning balance	$	10,227	$	10,227
	Changes to carrying value	—		—
	Ending balance	$	10,227	$	10,227
	Intangible Assets
	Intangible assets as of the dates indicated consisted of the following (in thousands):
		January 31, 2015
		Cost		Accumulated		Net Book
				Amortization		Value
	Acquired patent portfolio	$	65,000	$	35,595	$	29,405
	Core technology	36,100		29,447		6,653
	Patents and licenses	36,066		16,438		19,628
	Trademarks and tradenames	1,400		1,400		—
	Customer relationships	340		266		74
	Intangible assets, net	$	138,906	$	83,146	$	55,760
		April 30, 2014
		Cost		Accumulated		Net Book
				Amortization		Value
	Acquired patent portfolio	$	65,000	$	28,631	$	36,369
	Core technology	36,100		27,980		8,120
	Patents and licenses	36,066		14,438		21,628
	Trademarks and tradenames	1,400		1,400		—
	Customer relationships	340		240		100
	Intangible assets, net	$	138,906	$	72,689	$	66,217
	The following table presents the amortization of intangible assets recorded by the Company for the periods indicated (in thousands):
		Three Months Ended				Nine Months Ended
		January 31,				January 31,
		2015		2014		2015		2014
	Amortization of intangible assets	$	1,151	$	584	$	3,493	$	2,016
	Amortization of acquired patent portfolio	$	2,321	$	2,321	$	6,964	$	6,964
	The total expected future annual amortization of these intangible assets is as follows (in thousands):
	Years Ending April 30,
	2015	$	3,473
	2016	13,753
	2017	13,627
	2018	12,546
	2019	3,234
	Thereafter	9,127
	Total	$	55,760

Borrowing_Arrangements_and_Rel

Borrowing Arrangements and Related Derivative Instruments	9 Months Ended
	Jan. 31, 2015
Borrowing Arrangements and Related Derivative Instruments
Borrowing Arrangements and Related Derivative Instruments	Note 7 — Borrowing Arrangements and Related Derivative Instruments
	The following table sets forth the Company’s debt as of the dates indicated (in thousands):
		January 31,			April 30,
		2015			2014
	Mortgage loan	$	23,237		$	23,653
	Construction loan	8,962			12,179
		32,199			35,832
	Less: amount due within one year	(7,071		)	(3,802		)
	Non-current portion of long-term debt	$	25,128		$	32,030
	As of January 31, 2015, aggregate debt maturities were as follows (in thousands):
	Years Ending April 30,	Mortgage			Construction			Total
		Loan			Loan
	2015	$	139		$	—		$	139
	2016	553			6,518			7,071
	2017	22,545			2,444			24,989
	Total	$	23,237		$	8,962		$	32,199
	Mortgage Loan
	On March 16, 2007, the Company entered into a Loan and Security Agreement with a domestic bank for the purchase of a complex of four buildings located in Santa Clara, California (the “Santa Clara Property”). The Loan and Security Agreement provides for a mortgage loan in the principal amount of $27.9 million (the “Mortgage Loan”). The Mortgage Loan matures on March 31, 2017, and borrowings under the Mortgage Loan accrue interest at the London Interbank Borrowing Rate (“LIBOR”) plus 90 basis points. The Company was in compliance with the financial covenants of the Loan and Security Agreement as of January 31, 2015.
	Interest rates under the Mortgage Loan for the dates indicated are set forth below:
		January 31,		April 30,
		2015		2014
	Mortgage Loan	1.1	%	1.1	%
	In conjunction with the Mortgage Loan, the Company entered into an interest rate swap with the same bank to effectively convert the variable interest rate described above to a fixed rate. The swap is for a period of ten years, and the notional amount of the swap approximates the principal outstanding under the Mortgage Loan. The Company is the fixed rate payer under the swap and the rate is fixed at 5.3% per annum and the effective rate on the Mortgage Loan is fixed at approximately 6.2%.
	Construction Loan
	On August 3, 2009, OmniVision Technologies (Shanghai) Co. Ltd. (“OTC”), a wholly-owned subsidiary of the Company, entered into a Fixed Assets Loan Agreement with a bank in China (the “Construction Loan”). The purpose of the Construction Loan was to construct a research center for the Company in Pudong Development Zone, the Zhang Jiang Science Park in Shanghai, China. During the second quarter of fiscal 2011, the Company completed the construction of the research center. As of January 31, 2015, the total amount outstanding under the Construction Loan was Chinese Yuan 55 million, or approximately $9.0 million. The Construction Loan matures on June 30, 2016.
	The interest rate under the Construction Loan is based on an indicative rate as published by the Chinese government, and will be adjusted only at the anniversary of each drawdown. The interest rate under the Construction Loan was 5.9% at January 31, 2015 and April 30, 2014, respectively. The Company was in compliance with the financial covenants of the Fixed Assets Loan Agreement as of January 31, 2015.
	Derivative Instruments and Hedging Activities
	As indicated above, the Company entered into an interest rate swap in connection with the Mortgage Loan. The swap was set up to reduce the effect of interest rate variability on the Mortgage Loan’s interest payments, and is scheduled to expire in March 2017. The Company has not designated the interest rate swap as a hedging instrument. Consequently, the Company is remeasuring the interest rate swap at fair value at each subsequent balance sheet date, and immediately recognizing any changes to the fair value in earnings. On the condensed consolidated balance sheet, the Company records the swap as either an asset or a liability, depending on whether the fair value represents a gain or loss. (See Note 7.)
	The table below presents the location of the swap on the Condensed Consolidated Statements of Income and Condensed Consolidated Balance Sheets, and the related effect on the Company’s results of operations and financial positions for the periods indicated (in thousands):
		Three Months Ended						Nine Months Ended
		January 31,						January 31,
		2015			2014			2015		2014
	Location of amounts recognized in Condensed Consolidated Statements of Income and amount of gains:
	Other income, net	$	185		$	320		$	639	$	933
		January 31,			April 30,
		2015			2014
	Location of amounts on Condensed Consolidated Balance Sheets and fair values:
	Other long-term liabilities	$	2,341		$	2,980

Net_Income_Per_Share

Net Income Per Share	9 Months Ended
	Jan. 31, 2015
Net Income Per Share
Net Income Per Share	Note 8 — Net Income Per Share
	Basic net income per share is computed by dividing net income attributable to OmniVision by the weighted average number of common shares outstanding during the period.
	Diluted net income per share is computed according to the treasury stock method using the weighted average number of common and potentially dilutive common shares outstanding during the period. Potentially dilutive common shares represent the effect of stock options, purchases via employee stock purchase plans and restricted stock units. The following table sets forth the number of stock options that were excluded from the calculation of diluted net income per share because they were antidilutive for the periods indicated:
		Three Months Ended				Nine Months Ended
		January 31,				January 31,
		2015		2014		2015	2014
	Antidilutive common stock subject to outstanding options	508,000		2,513,000		661,000	2,513,000
	The following table sets forth the computation of basic and diluted earnings per share for the periods indicated (in thousands, except per share data):
		Three Months Ended					Nine Months Ended
		January 31,					January 31,
		2015			2014		2015		2014
	Basic:
	Numerator:
	Net income	$	14,023		$	30,560	$	87,394	$	79,924
	Denominator:
	Weighted average common shares for net income per share	57,948			55,913		57,383		55,369
	Basic net income per share	$	0.24		$	0.55	$	1.52	$	1.44
	Diluted:
	Numerator:
	Net income	$	14,023		$	30,560	$	87,394	$	79,924
	Denominator:
	Denominator for basic net income per share	57,948			55,913		57,383		55,369
	Weighted average effect of dilutive securities:
	Stock options, restricted stock units and employee stock purchase plan shares	2,186			273		1,855		1,103
	Weighted average common shares for diluted net income per share	60,134			56,186		59,238		56,472
	Diluted net income per share	$	0.23		$	0.54	$	1.48	$	1.42

Fair_Value_Measurements

Fair Value Measurements	9 Months Ended
	Jan. 31, 2015
Fair Value Measurements
Fair Value Measurements	Note 9 — Fair Value Measurements
	The authoritative guidance for fair value measurements specifies a hierarchy of valuation techniques based upon whether the inputs to those valuation techniques reflect assumptions other market participants would use based upon market data obtained from independent sources (observable inputs) or reflect the Company’s own assumption of market participant valuation (unobservable inputs). The fair value hierarchy consists of the following three levels:
		·		Level 1 — Inputs are quoted prices in active markets for identical assets or liabilities.
		·		Level 2 — Inputs are quoted prices for similar assets or liabilities in an active market, quoted prices for identical or similar assets or liabilities in markets that are not active, inputs other than quoted prices that are observable and market-corroborated inputs which are derived principally from or corroborated by observable market data.
		·		Level 3 — Inputs are derived from valuation techniques in which one or more significant inputs or value drivers are unobservable.
	Assets and Liabilities Measured and Recorded at Fair Value on a Recurring Basis
	The following table presents the Company’s financial assets and liabilities that are measured at fair value on a recurring basis which were comprised of the following types of instruments as of the date indicated (in thousands):
			January 31, 2015
			Total			Level 1		Level 2			Level 3
	Money market funds		$	17,005		$	17,005	$	—		$	—
	U.S. government debt securities and municipal bonds		46,646			—		46,646			—
	Corporate debt securities/commercial paper		217,496			—		217,496			—
	Total assets		$	281,147		$	17,005	$	264,142		$	—
	Interest rate swap		(2,341		)	—		(2,341		)	—
	Total liabilities		$	(2,341	)	$	—	$	(2,341	)	$	—
	The following table presents the Company’s financial assets and liabilities that are measured at fair value on a recurring basis which were presented on the Company’s Condensed Consolidated Balance Sheets as of the date indicated (in thousands):
			January 31, 2015
			Total			Level 1		Level 2			Level 3
	Cash equivalents		$	76,521		$	17,005	$	59,516		$	—
	Short-term investments		204,626			—		204,626			—
	Total assets		$	281,147		$	17,005	$	264,142		$	—
	Interest rate swap		(2,341		)	—		(2,341		)	$	—
	Total liabilities		$	(2,341	)	$	—	$	(2,341	)	$	—
	The following table presents the Company’s financial assets and liabilities that are measured at fair value on a recurring basis which were comprised of the following types of instruments as of the date indicated (in thousands):
			April 30, 2014
			Total			Level 1		Level 2			Level 3
	Money market funds		$	57,207		$	57,207	$	—		$	—
	U.S. government debt securities and municipal bonds		17,834			—		17,834			—
	Corporate debt securities/commercial paper		180,764			—		180,764			—
	Total assets		$	255,805		$	57,207	$	198,598		$	—
	Interest rate swap		$	(2,980	)	$	—	$	(2,980	)	$	—
	Total liabilities		$	(2,980	)	$	—	$	(2,980	)	$	—
	The following table presents the Company’s financial assets and liabilities that are measured at fair value on a recurring basis which were presented on the Company’s Condensed Consolidated Balance Sheets as of the date indicated (in thousands):
			April 30, 2014
			Total			Level 1		Level 2			Level 3
	Cash equivalents		$	102,812		$	57,207	$	45,605		$	—
	Short-term investments		152,993			—		152,993			—
	Total assets		$	255,805		$	57,207	$	198,598		$	—
	Interest rate swap		$	(2,980	)	$	—	$	(2,980	)	$	—
	Total liabilities		$	(2,980	)	$	—	$	(2,980	)	$	—
	For the Company’s interest rate swap, the Company obtains fair value quotes from the issuing bank and assesses the quotes for reasonableness by comparing them to the present values of expected cash flows. The present value approach is based on observable market interest rate curves that are commensurate with the terms of the interest rate swap. The carrying value represents the fair value of the swap, as adjusted for any non-performance risk associated with the Company.
	Due to their short maturities, the reported amounts of the Company’s financial instruments, including cash equivalents, short-term investments, accounts receivable, accounts payable and other current liabilities approximate their fair values.
	For its investment in WLCSP, the Company uses the equity method of accounting. (See Note 5.) As of January 31, 2015, using the per share closing price of the stock of $8.60 on the Shanghai Stock Exchange (categorized as Level 1 for purposes of the fair value hierarchy), the aggregate fair value of the Company’s investment in WLCSP totaled approximately $260.2 million.
	The Mortgage Loan and the Construction Loan are recorded at cost. Their book values, however, approximate fair values as the underlying interest rates are based on risk-adjusted market rates; they are categorized as Level 2 for purposes of the fair value measurement hierarchy.

Segment_and_Geographic_Informa

Segment and Geographic Information	9 Months Ended
	Jan. 31, 2015
Segment and Geographic Information
Segment and Geographic Information	Note 10 — Segment and Geographic Information
	For all periods presented, the Company operated as a single reportable business segment.
	The Company sells its image-sensor products either directly to original equipment manufacturers (“OEMs”) and value added resellers (“VARs”) or indirectly through distributors. The following table illustrates the percentage of revenues from sales to OEMs and VARs and to distributors for the periods indicated, respectively:
		Three Months Ended				Nine Months Ended
		January 31,				January 31,
		2015		2014		2015		2014
	OEMs and VARs	74.4	%	80.3	%	75.0	%	82.1	%
	Distributors	25.6		19.7		25.0		17.9
	Total	100.0	%	100.0	%	100.0	%	100.0	%
	Since the Company’s customers’ end-user customers market and sell their products worldwide, the Company’s revenues by geographic location are not necessarily indicative of the geographic distribution of end-user sales, but rather indicate where their components are sourced. The revenues by geography in the following table are based on the country or region in which the Company’s customers issue their purchase orders for the periods presented (in thousands):
		Three Months Ended						Nine Months Ended
		January 31,						January 31,
		2015			2014			2015		2014
	China	$	223,462		$	259,935		$	879,521	$	844,764
	Japan	19,523			33,006			66,892		76,776
	Singapore	15,119			6,325			25,965		11,181
	South Korea	9,969			36,466			56,460		140,227
	United States	4,579			1,146			8,947		3,907
	All other	19,689			15,145			55,137		46,105
	Total	$	292,341		$	352,023		$	1,092,922	$	1,122,960
	The Company’s long-lived assets, including its property, plant and equipment, net, long-term investments, land-use rights and other long-term assets, were located in the following countries as of the dates indicated (in thousands):
		January 31,			April 30,
		2015			2014
	China	$	156,411		$	162,207
	Taiwan	112,297			126,820
	United States	48,391			50,552
	All other	825			623
	Total	$	317,924		$	340,202

Supplemental_Financial_Informa

Supplemental Financial Information	9 Months Ended
	Jan. 31, 2015
Supplemental Financial Information
Supplemental Financial Information	Note 11 — Supplemental Financial Information
	Additional Paid-in Capital
	The following table shows the amounts recorded to “Additional paid-in capital” for the nine months ended January 31, 2015 (in thousands):
		Additional
		Paid-in
		Capital
	Balance at April 30, 2014	$	664,602
	Exercise of common stock options	5,116
	Employee stock purchase plan	7,719
	Employee stock-based compensation	25,816
	Withholding tax deduction on restricted stock units	(4,185		)
	Tax effect from stock-based compensation	2,458
	Write-off of employee stock-based compensation related deferred tax assets	(858		)
	Balance at January 31, 2015	$	700,668
	Accumulated Other Comprehensive Income
	The following table presents the components of, and the changes in, accumulated other comprehensive income for the nine months ended January 31, 2015 (in thousands):
		Balance at			Other			Amounts			Related Tax			Balance at
		April 30,			Comprehensive			Reclassified out			Effects			January 31,
		2014			Income Before			of Accumulated						2015
					Reclassification			Other
								Comprehensive
								Income
	Accumulated translation gains	$	2,406		$	165		$	—		$	(58	)	$	2,513
	Accumulated unrealized gains (losses) on available-for-sale securities, net	(28		)	35			(1		)	(12		)	(6		)
	Total accumulated other comprehensive income	$	2,378		$	200		$	(1	)	$	(70	)	$	2,507
	The following table sets forth the amounts reclassified out of Accumulated Other Comprehensive Income into the Condensed Consolidated Statements of Income and the associated presentation location, for the periods indicated (in thousands):
				Three Months Ended						Nine Months Ended
	Comprehensive Income			January 31,						January 31,
	Components	Location		2015			2014			2015			2014
	Accumulated translation gains	Other income, net		$	—		$	(1,023	)	$	—		$	(1,023	)
	Accumulated unrealized gains (losses) on available-for-sale securities, net
		Other income, net		—			—			(1		)	(1,641		)
		Total amounts reclassified out of Accumulated Other Comprehensive Income		$			$	(1,023	)	$	(1	)	$	(2,664	)

Income_Taxes

Income Taxes	9 Months Ended
	Jan. 31, 2015
Income Taxes
Income Taxes	Note 12 — Income Taxes
	The Company reported the following operating results for the periods presented (in thousands):
		Three Months Ended						Nine Months Ended
		January 31,						January 31,
		2015			2014			2015			2014
	Income before income taxes	$	10,805		$	42,256		$	75,103		$	86,678
	Provision for (benefit from) income taxes	$	(3,218	)	$	11,696		$	(12,291	)	$	6,754
	Effective income tax rate	(29.8		)%	27.7		%	(16.4		)%	7.8		%
	The Company’s effective income tax rate reflects the impact of a significant amount of the Company’s earnings being taxed in foreign jurisdictions at rates below the U.S. statutory tax rate. The Tax Increase Prevention Act, which was signed into law on December 19, 2014, retroactively extended the U.S. Federal research and development tax credit (“Federal R&D Credit”) from January 1, 2014 to December 31, 2014.
	The Company’s quarterly income taxes reflect an estimate of the corresponding fiscal year’s annual effective tax rate and include, when applicable, adjustments from discrete tax items. For the three months ended January 31, 2015, the discrete adjustments to the Company’s provision for income taxes included favorable adjustments from the decrease of the Company’s gross unrecognized tax benefits, related to the conclusion of a tax examination in a foreign jurisdiction and the lapse of applicable statute of limitation in another jurisdiction, the tax benefit from the one-year retroactive extension of the Federal R&D Credit, and the favorable adjustments to tax provisions from prior years. These favorable discrete adjustments were partially offset by the income tax expenses accrued on undistributed earnings for certain non-U.S. investee companies.
	The Company was under tax examination in a foreign jurisdiction, starting from the fiscal year ended April 30, 2004. This tax examination was concluded in November 2014, with the Company reaching a settlement agreement with the foreign jurisdiction taxing authority that covered from fiscal year ended April 30, 2004 to fiscal year ended April 30, 2013. Consequently, during the three months ended January 31, 2015, the Company reduced its gross unrecognized tax benefits by approximately $5.4 million and recorded a $2.9 million benefit from income taxes. During the three months ended January 31, 2015, the Company accrued an additional $359,000 of interest related to the Company’s unrecognized tax benefits. The Company anticipates that the balance of gross unrecognized tax benefits as of January 31, 2015 will decrease by approximately $5.3 million due to the lapse of the applicable statutes of limitations in certain jurisdictions over the next 12 months.

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
	Jan. 31, 2015
Commitments and Contingencies
Commitments and Contingencies	Note 13 — Commitments and Contingencies
	Commitments
	During the three months ended July 31, 2014, in an effort to enhance the research and development capabilities of OTC, the Company increased OTC’s registered capital requirement from $12.0 million to $27.0 million. In December 2014, the Company contributed the incremental $15.0 million to OTC, meeting the registered capital commitment requirement.
	During the three months ended July 31, 2014, the Company entered into a development and supply agreement with Powerchip Technology Corporation (“PTC”) pursuant to which the Company would deposit up to $1.0 million with PTC as prepaid wafer credit. As of January 31, 2015, the Company has not made any deposits under this agreement.
	Litigation
	From time to time, the Company has been subject to legal proceedings and claims with respect to such matters as patents, product liabilities and other actions arising out of the normal course of business.
	Ziptronix, Inc. v. OmniVision Technologies, Inc., Taiwan Semiconductor Manufacturing Company Ltd., and TSMC North America Corp.
	On December 6, 2010, Ziptronix, Inc. (“Ziptronix”) filed a complaint alleging patent infringement against the Company in the District Court for the Northern District of California. The case is entitled Ziptronix, Inc. v. OmniVision Technologies, Inc., Taiwan Semiconductor Manufacturing Company Ltd., and TSMC North America Corp., Case No. CV10-05525. In its complaint, Ziptronix asserts that the Company has made, used, offered to sell, sold and/or imported into the United States image sensors that infringe the following six patents: U.S. Patent Nos. 7,387,944 (“Method for Low Temperature Bonding and Bonded Structure”), 7,335,572 (“Method for Low Temperature Bonding and Bonded Structure”), 7,553,744 (“Method for Low Temperature Bonding and Bonded Structure”), 7,037,755 (“Three Dimensional Device Integration Method and Integrated Device”), 6,864,585 (“Three Dimensional Device Integration Method and Integrated Device”), and 7,807,549 (“Method for Low Temperature Bonding and Bonded Structure”). The complaint seeks unspecified monetary damages, enhanced damages, interest, fees, expenses, costs, and injunctive relief against the Company. The Company answered the complaint on May 4, 2011 and denied each of Ziptronix’s infringement claims against it.
	On November 22, 2011, Defendants Taiwan Semiconductor Manufacturing Company Ltd., and TSMC North America Corp. (collectively “TSMC”) filed amended counterclaims asserting that Ziptronix has infringed, actively induced infringement of, and/or induced contributory infringement of the following five patents: U.S. Patent Nos. 6,682,981 (“Stress Controlled Dielectric Integrated Circuit Fabrication”), 7,307,020 (“Membrane 3D IC Fabrication”), 6,765,279 (“Membrane 3D IC Fabrication”), 7,385,835 (“Membrane 3D IC Fabrication”), and 6,350,694 (“Reducing CMP Scratch, Dishing and Erosion by Post CMP Etch Back Method for Low-K Materials”). Ziptronix answered the amended counterclaims on December 9, 2011 and denied each of TSMC’s infringement claims against it.
	On August 9, 2012, Ziptronix filed a second amended complaint adding claims that the defendants infringe the following three patents: U.S. Patent Nos. 8,153,505 (“Method for Low Temperature Bonding and Bonded Structure”), 8,043,329 (“Method for Low Temperature Bonding and Bonded Structure”), and 7,871,898 (“Method for Low Temperature Bonding and Bonded Structure”). The Company answered the second amended complaint on August 27, 2012, and denied each of Ziptronix’s infringement claims against it.
	Claim construction briefing has been submitted, but there is no claim construction hearing currently scheduled. On September 30, 2014, the court granted TSMC’s motion for summary judgment of noninfringement based on extraterritoriality issues. On March 2, 2015, the court granted the Company’s motion for summary judgment of noninfringement of its non-U.S. sales. A case management conference is scheduled for March 19, 2015, to discuss the issues that remain in the case. The court’s recent summary judgment motion addresses most of Ziptronix’s infringement claims asserted in the case and the Company expects to vigorously defend itself against Ziptronix’s remaining allegations of infringement. The Company is currently unable to predict the ultimate outcome of this case and therefore cannot determine the likelihood of loss nor estimate the loss or a range of possible loss.
	Securities Litigation
	On October 26, 2011, the first of several putative class action complaints was filed in the United States District Court for the Northern District of California against the Company and three of its executives, one of whom is a director. All of the complaints alleged that the defendants violated the federal securities laws by making misleading statements or omissions regarding the Company’s business and financial results, in particular regarding the use of its imaging sensors in Apple Inc.’s iPhone. These actions have been consolidated as In re OmniVision Technologies, Inc. Litigation,  Case No. 11-CV-5235 (RMW) (the “Securities Case”). On April 23, 2012, plaintiffs filed a consolidated complaint on behalf of a purported class of purchasers of the Company’s common stock between August 27, 2010 and November 6, 2011, seeking unspecified damages. On March 29, 2013, the court denied the defendants’ motion to dismiss. On December 30, 2014, the parties entered into a stipulation and agreement of settlement to resolve the litigation, which was then submitted to the court for preliminary approval. The stipulation and agreement of settlement provides for a payment of $12.5 million to the plaintiff class, which is funded solely by the Company’s insurance carriers. The Company also entered into a mutual release agreement with one of its insurance carriers. In March 2015, the court entered an order granting preliminary approval of the settlement and ordering notice to the putative plaintiff class. The court also scheduled a June 2015 hearing regarding final approval of the settlement.
	With the execution of the stipulation agreement and the release agreement, the Company believes that ultimate settlement is probable, at the currently estimated amount. Consequently, as of January 31, 2015, on the condensed consolidated balance sheet, the Company recorded $12.5 million in Recoverable insurance proceeds within Total current assets, and $12.5 million in Litigation settlement accrual within Total current liabilities. Notice of the settlement must be provided to the putative shareholder class, and the court must grant final approval of the settlement. There is no assurance that the court will grant such approval, or that the settlement will become final. If the settlement does not occur and litigation against the Company continues, the Company believes that it has meritorious defenses and intends to defend the case vigorously.
	Derivative Litigation
	On November 15, 2011, the first of three shareholder derivative complaints was filed in the Superior Court of California, County of Santa Clara, against several of the Company’s current and former officers and directors. These three state court actions were consolidated under the caption In re OmniVision Technologies, Inc. Derivative Litigation, Case No. 1-12-CV-216875. On March 21, 2012, a fourth similar shareholder derivative complaint captioned Carpenters Pension Fund of West Virginia v. Shaw Hong, et al., Case No. 12-CV-1423, was filed in the United States District Court for the Northern District of California. On May 10, 2012, a fifth similar shareholder derivative complaint captioned Edker Pope v. Shaw Hong, et. al., Case No. 7514, was filed in the Court of Chancery of the State of Delaware. These complaints make allegations similar to those presented in Securities Case, but they assert various state law causes of action, including claims of breach of fiduciary duty and unjust enrichment. All of these derivative complaints seek unspecified damages on behalf of the Company, which is named solely as nominal defendant against whom no recovery is sought. The proceedings in these derivative actions have been stayed by agreement. The Company is currently unable to predict the outcome of these actions and therefore cannot determine the likelihood of loss nor estimate the loss or a range of possible loss.

Related_Party_Transactions

Related Party Transactions	9 Months Ended
	Jan. 31, 2015
Related Party Transactions
Related Party Transactions	Note 14 — Related Party Transactions
	The following table presents the amounts paid for services provided by related parties and the balances payable for the periods indicated (in thousands):
			Three Months Ended				Nine Months Ended
	Related		January 31,				January 31,
	Party	Description	2015		2014		2015		2014
	VisEra	Purchases of color filter and other manufacturing services	$	25,945	$	22,191	$	77,620	$	93,422
		Rent and other services	$	—	$	—	$	—	$	3
		Balances payable at period end, net	$	18,116	$	23,066	$	18,116	$	23,066
	WLCSP	Purchases of packaging services	$	8,358	$	393	$	19,354	$	436
		Balances payable at period end, net	$	4,376	$	223	$	4,376	$	223

Basis_of_Presentation_Policies

Basis of Presentation (Policies)	9 Months Ended
	Jan. 31, 2015
Basis of Presentation
Use of Estimates	Use of Estimates
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America (“GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. The Company bases its estimates and judgments on its historical experience, knowledge of current conditions and beliefs of what could occur in the future considering available information. Actual results could differ from these estimates.

ShortTerm_Investments_Tables

Short-Term Investments (Tables)	9 Months Ended
	Jan. 31, 2015
Short-Term Investments
Schedule of available-for-sale securities
	Available-for-sale securities as of the dates presented were as follows (in thousands):
		As of January 31, 2015
		Amortized		Gross		Gross			Fair
				Unrealized		Unrealized
		Cost		Gains		Losses			Value
	Municipal bonds	$	9,205	$	—	$	(3	)	$	9,202
	U.S. government debt securities with maturities less than one year	26,652		4					26,656
	Corporate debt securities/commercial paper	168,778		13		(23		)	168,768
		$	204,635	$	17	$	(26	)	$	204,626
	Contractual maturity dates, less than one year								$	201,569
	Contractual maturity dates, one to two years								3,057
									$	204,626
		As of April 30, 2014
		Amortized		Gross		Gross			Fair
				Unrealized		Unrealized
		Cost		Gains		Losses			Value
	Municipal bonds	$	6,168	$	1	$	(2	)	$	6,167
	Corporate debt securities/commercial paper	146,866		6		(46		)	146,826
		$	153,034	$	7	$	(48	)	$	152,993
	Contractual maturity dates, less than one year								$	142,758
	Contractual maturity dates, one to two years								10,235
									$	152,993

Supplemental_Balance_Sheet_Acc1

Supplemental Balance Sheet Account Information (in thousands) (Tables)	9 Months Ended
	Jan. 31, 2015
Supplemental Balance Sheet Account Information (in thousands)
Schedule of supplemental balance sheet account information	Supplemental Balance Sheet Account Information (in thousands)
		January 31,			April 30,
		2015			2014
	Cash and cash equivalents:
	Cash	$	231,640		$	195,141
	Money market funds, commercial paper and U.S. government bonds	76,521			102,811
		$	308,161		$	297,952
	Accounts receivable, net:
	Accounts receivable	$	144,758		$	176,576
	Less:  Allowance for doubtful accounts	(886		)	(998		)
	Allowance for sales returns	(2,166		)	(3,106		)
		$	141,706		$	172,472
	Inventories:
	Work in progress	$	173,686		$	107,621
	Finished goods	192,693			163,314
		$	366,379		$	270,935
	Prepaid expenses and other current assets:
	Prepaid expenses	$	5,109		$	4,285
	Deposits and other	331			1,284
	Interest receivable	1,033			1,007
		$	6,473		$	6,576
	Property, plant and equipment, net:
	Land	$	13,000		$	13,000
	Buildings	82,623			82,547
	Buildings/leasehold improvements	29,318			29,123
	Machinery and equipment	120,046			119,762
	Furniture and fixtures	5,030			5,002
	Software	8,853			8,774
	Construction in progress	1,998			2,894
		260,868			261,102
	Less: Accumulated depreciation and amortization	(112,352		)	(107,310		)
		$	148,516		$	153,792
	Other long-term assets:
	Deferred tax assets — non-current	$	1,096		$	528
	Land-use rights	2,137			2,180
	Other long-term assets	21,961			29,821
		$	25,194		$	32,529
	Accrued expenses and other current liabilities:
	Deferred tax liabilities — current	$	144		$	144
	Employee compensation	12,677			15,176
	Third party commissions	511			380
	Professional services	2,574			2,270
	Noncancelable purchase commitments	729			647
	Rebates	1,896			1,511
	Other	10,052			11,831
		$	28,583		$	31,959
	Other long-term liabilities:
	Interest rate swap	$	2,341		$	2,980
	Deferred tax liabilities — non-current	12,992			3,731
	Other	6,520			5,107
		$	21,853		$	11,818

Longterm_Investments_Tables

Long-term Investments (Tables)	9 Months Ended
	Jan. 31, 2015
Long-term investment disclosures
Schedule of long-term investments	Long-term investments as of the dates indicated consisted of the following (in thousands):
		January 31,			April 30,
		2015			2014
	VisEra	$	103,402		$	115,943
	WLCSP	37,247			33,805
	XinTec	4,661			4,661
	Total	$	145,310		$	154,409
Schedule of Company's share of undistributed earnings of investees accounted for by equity method
	The Company’s share of undistributed earnings of investees accounted for by the equity method as of the dates indicated were as follows (in thousands):
		January 31,			April 30,
		2015			2014
	Undistributed earnings of investees	$	56,431		$	66,772
Vis Era Technologies Company Limited [Member] | Dividends Received From Investee [Member]
Long-term investment disclosures
Schedule of dividends received, equity income and summary financial information
	The Company received the following dividend payments from VisEra during the periods presented (in thousands):
		Nine Months Ended
		January 31,
		2015			2014
	Dividend payments received from VisEra	$	17,101		$	—
Vis Era Technologies Company Limited [Member] | Equity Income [Member]
Long-term investment disclosures
Schedule of dividends received, equity income and summary financial information	The following table presents equity income before elimination of unrealized intercompany profits and the equity income recorded by the Company for the periods indicated in “Cost of revenues,” consisting of its portion of the net income recorded by VisEra during the periods presented after the elimination of unrealized intercompany profits (in thousands).
		Three Months Ended						Nine Months Ended
		January 31,						January 31,
		2015			2014			2015			2014
	Equity income (losses)	$	680		$	(331	)	$	4,560		$	10,079
	Net effect on Cost of revenues, after the elimination of unrealized intercompany profits	$	(81	)	$	4,220		$	4,213		$	16,378
Vis Era Technologies Company Limited [Member] | Summary Financial Information [Member]
Long-term investment disclosures
Schedule of dividends received, equity income and summary financial information	Each of the investee’s statement was prepared under US GAAP (in thousands).
	VisEra Technologies Company, Ltd.
		Three Months Ended						Nine Months Ended
		January 31,						January 31,
		2015			2014			2015			2014
	Operating data:
	Revenues	$	28,998		$	24,236		$	86,002		$	103,500
	Gross profit	5,962			13,147			21,240			46,866
	Income from operations	3,746			10,567			14,328			38,953
	Net income (loss)	$	(165	)	$	8,588		$	8,574		$	33,328
China W L C S P Limited [Member] | Dividends Received From Investee [Member]
Long-term investment disclosures
Schedule of dividends received, equity income and summary financial information
	The Company received the following dividend payments from WLCSP during the periods presented (in thousands):
		Nine Months Ended
		January 31,
		2015			2014
	Dividend payments received from WLCSP	$	726		$	830
China W L C S P Limited [Member] | Equity Income [Member]
Long-term investment disclosures
Schedule of dividends received, equity income and summary financial information	The following table presents equity income recorded by the Company for the periods indicated in “Equity in earnings of investee,” consisting of its portion of the net income recorded by WLCSP during the periods presented, and equity method investment adjustments (in thousands).
		Three Months Ended						Nine Months Ended
		January 31,						January 31,
		2015			2014			2015			2014
	Equity income	$	1,279		$	837		$	3,248		$	3,264
China W L C S P Limited [Member] | Summary Financial Information [Member]
Long-term investment disclosures
Schedule of dividends received, equity income and summary financial information
	Each of the investee’s statement was prepared under US GAAP (in thousands).
	China WLCSP Limited
		Three Months Ended							Nine Months Ended
		December 31,							December 31,
		2014			2013				2014			2013
	Operating data:
	Revenues	$	32,022		$	20,111			$	78,082		$	58,651
	Gross profit	14,064			11,522				40,428			32,176
	Income from operations	7,125			6,415				21,928			21,712
	Net income	$	9,589		$		6,474		$	24,333		$		18,736

Goodwill_and_Intangible_Assets1

Goodwill and Intangible Assets (Tables)	9 Months Ended
	Jan. 31, 2015
Goodwill and Intangible Assets
Schedule of change to carrying value of goodwill	The following table summarizes the change to the carrying value of the Company’s goodwill during the periods presented (in thousands):
		Nine Months Ended
		January 31,
		2015		2014
	Beginning balance	$	10,227	$	10,227
	Changes to carrying value	—		—
	Ending balance	$	10,227	$	10,227
Schedule of intangible assets	Intangible assets as of the dates indicated consisted of the following (in thousands):
		January 31, 2015
		Cost		Accumulated		Net Book
				Amortization		Value
	Acquired patent portfolio	$	65,000	$	35,595	$	29,405
	Core technology	36,100		29,447		6,653
	Patents and licenses	36,066		16,438		19,628
	Trademarks and tradenames	1,400		1,400		—
	Customer relationships	340		266		74
	Intangible assets, net	$	138,906	$	83,146	$	55,760
		April 30, 2014
		Cost		Accumulated		Net Book
				Amortization		Value
	Acquired patent portfolio	$	65,000	$	28,631	$	36,369
	Core technology	36,100		27,980		8,120
	Patents and licenses	36,066		14,438		21,628
	Trademarks and tradenames	1,400		1,400		—
	Customer relationships	340		240		100
	Intangible assets, net	$	138,906	$	72,689	$	66,217
Schedule of amortization of intangible assets	The following table presents the amortization of intangible assets recorded by the Company for the periods indicated (in thousands):
		Three Months Ended				Nine Months Ended
		January 31,				January 31,
		2015		2014		2015		2014
	Amortization of intangible assets	$	1,151	$	584	$	3,493	$	2,016
	Amortization of acquired patent portfolio	$	2,321	$	2,321	$	6,964	$	6,964
Schedule of expected future annual amortization of intangible assets
	The total expected future annual amortization of these intangible assets is as follows (in thousands):
	Years Ending April 30,
	2015	$	3,473
	2016	13,753
	2017	13,627
	2018	12,546
	2019	3,234
	Thereafter	9,127
	Total	$	55,760

Borrowing_Arrangements_and_Rel1

Borrowing Arrangements and Related Derivative Instruments (Tables)	9 Months Ended
	Jan. 31, 2015
Borrowing Arrangements and Related Derivative Instruments
Schedule of the Company's debt	The following table sets forth the Company’s debt as of the dates indicated (in thousands):
		January 31,			April 30,
		2015			2014
	Mortgage loan	$	23,237		$	23,653
	Construction loan	8,962			12,179
		32,199			35,832
	Less: amount due within one year	(7,071		)	(3,802		)
	Non-current portion of long-term debt	$	25,128		$	32,030
Schedule of aggregate debt maturities	As of January 31, 2015, aggregate debt maturities were as follows (in thousands):
	Years Ending April 30,	Mortgage			Construction			Total
		Loan			Loan
	2015	$	139		$	—		$	139
	2016	553			6,518			7,071
	2017	22,545			2,444			24,989
	Total	$	23,237		$	8,962		$	32,199
Schedule of interest rates of mortgage loan
		January 31,		April 30,
		2015		2014
	Mortgage Loan	1.1	%	1.1	%
Schedule of location of swaps on condensed consolidated statements of income and condensed consolidated balance sheets, and related effects on entity's results of operations and financial positions	The table below presents the location of the swap on the Condensed Consolidated Statements of Income and Condensed Consolidated Balance Sheets, and the related effect on the Company’s results of operations and financial positions for the periods indicated (in thousands):
		Three Months Ended						Nine Months Ended
		January 31,						January 31,
		2015			2014			2015		2014
	Location of amounts recognized in Condensed Consolidated Statements of Income and amount of gains:
	Other income, net	$	185		$	320		$	639	$	933
		January 31,			April 30,
		2015			2014
	Location of amounts on Condensed Consolidated Balance Sheets and fair values:
	Other long-term liabilities	$	2,341		$	2,980

Net_Income_Per_Share_Tables

Net Income Per Share (Tables)	9 Months Ended
	Jan. 31, 2015
Net Income Per Share
Schedule of antidilutive securities excluded from computation of income per share
		Three Months Ended				Nine Months Ended
		January 31,				January 31,
		2015		2014		2015	2014
	Antidilutive common stock subject to outstanding options	508,000		2,513,000		661,000	2,513,000
Schedule of computation of basic and diluted earnings per share
	The following table sets forth the computation of basic and diluted earnings per share for the periods indicated (in thousands, except per share data):
		Three Months Ended					Nine Months Ended
		January 31,					January 31,
		2015			2014		2015		2014
	Basic:
	Numerator:
	Net income	$	14,023		$	30,560	$	87,394	$	79,924
	Denominator:
	Weighted average common shares for net income per share	57,948			55,913		57,383		55,369
	Basic net income per share	$	0.24		$	0.55	$	1.52	$	1.44
	Diluted:
	Numerator:
	Net income	$	14,023		$	30,560	$	87,394	$	79,924
	Denominator:
	Denominator for basic net income per share	57,948			55,913		57,383		55,369
	Weighted average effect of dilutive securities:
	Stock options, restricted stock units and employee stock purchase plan shares	2,186			273		1,855		1,103
	Weighted average common shares for diluted net income per share	60,134			56,186		59,238		56,472
	Diluted net income per share	$	0.23		$	0.54	$	1.48	$	1.42

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	9 Months Ended
	Jan. 31, 2015
Fair Value Measurements
Schedule of financial assets and liabilities measured at fair value on a recurring basis comprising types of instruments	The following table presents the Company’s financial assets and liabilities that are measured at fair value on a recurring basis which were comprised of the following types of instruments as of the date indicated (in thousands):
		January 31, 2015
		Total			Level 1		Level 2			Level 3
	Money market funds	$	17,005		$	17,005	$	—		$	—
	U.S. government debt securities and municipal bonds	46,646			—		46,646			—
	Corporate debt securities/commercial paper	217,496			—		217,496			—
	Total assets	$	281,147		$	17,005	$	264,142		$	—
	Interest rate swap	(2,341		)	—		(2,341		)	—
	Total liabilities	$	(2,341	)	$	—	$	(2,341	)	$	—
	The following table presents the Company’s financial assets and liabilities that are measured at fair value on a recurring basis which were comprised of the following types of instruments as of the date indicated (in thousands):
		April 30, 2014
		Total			Level 1		Level 2			Level 3
	Money market funds	$	57,207		$	57,207	$	—		$	—
	U.S. government debt securities and municipal bonds	17,834			—		17,834			—
	Corporate debt securities/commercial paper	180,764			—		180,764			—
	Total assets	$	255,805		$	57,207	$	198,598		$	—
	Interest rate swap	$	(2,980	)	$	—	$	(2,980	)	$	—
	Total liabilities	$	(2,980	)	$	—	$	(2,980	)	$	—
Schedule of financial assets and liabilities measured at fair value on a recurring basis presented on the entity's Condensed consolidated balance sheets	The following table presents the Company’s financial assets and liabilities that are measured at fair value on a recurring basis which were presented on the Company’s Condensed Consolidated Balance Sheets as of the date indicated (in thousands):
		January 31, 2015
		Total			Level 1		Level 2			Level 3
	Cash equivalents	$	76,521		$	17,005	$	59,516		$	—
	Short-term investments	204,626			—		204,626			—
	Total assets	$	281,147		$	17,005	$	264,142		$	—
	Interest rate swap	(2,341		)	—		(2,341		)	$	—
	Total liabilities	$	(2,341	)	$	—	$	(2,341	)	$	—
	The following table presents the Company’s financial assets and liabilities that are measured at fair value on a recurring basis which were presented on the Company’s Condensed Consolidated Balance Sheets as of the date indicated (in thousands):
		April 30, 2014
		Total			Level 1		Level 2			Level 3
	Cash equivalents	$	102,812		$	57,207	$	45,605		$	—
	Short-term investments	152,993			—		152,993			—
	Total assets	$	255,805		$	57,207	$	198,598		$	—
	Interest rate swap	$	(2,980	)	$	—	$	(2,980	)	$	—
	Total liabilities	$	(2,980	)	$	—	$	(2,980	)	$	—

Segment_and_Geographic_Informa1

Segment and Geographic Information (Tables)	9 Months Ended
	Jan. 31, 2015
Segment and Geographic Information
Schedule of revenues by customer segment
		Three Months Ended				Nine Months Ended
		January 31,				January 31,
		2015		2014		2015		2014
	OEMs and VARs	74.4	%	80.3	%	75.0	%	82.1	%
	Distributors	25.6		19.7		25.0		17.9
	Total	100.0	%	100.0	%	100.0	%	100.0	%
Schedule of revenues by geography based on the country or region in which the Company's customers issue their purchase orders	The revenues by geography in the following table are based on the country or region in which the Company’s customers issue their purchase orders for the periods presented (in thousands):
		Three Months Ended						Nine Months Ended
		January 31,						January 31,
		2015			2014			2015		2014
	China	$	223,462		$	259,935		$	879,521	$	844,764
	Japan	19,523			33,006			66,892		76,776
	Singapore	15,119			6,325			25,965		11,181
	South Korea	9,969			36,466			56,460		140,227
	United States	4,579			1,146			8,947		3,907
	All other	19,689			15,145			55,137		46,105
	Total	$	292,341		$	352,023		$	1,092,922	$	1,122,960
Schedule of the Company's long-lived assets, including its property, plant and equipment, net, long-term investments, land-use rights and other long-term assets	The Company’s long-lived assets, including its property, plant and equipment, net, long-term investments, land-use rights and other long-term assets, were located in the following countries as of the dates indicated (in thousands):
		January 31,			April 30,
		2015			2014
	China	$	156,411		$	162,207
	Taiwan	112,297			126,820
	United States	48,391			50,552
	All other	825			623
	Total	$	317,924		$	340,202

Supplemental_Financial_Informa1

Supplemental Financial Information (Tables)	9 Months Ended
	Jan. 31, 2015
Supplemental Financial Information
Schedule of amounts recorded to "Additional paid-in capital"	The following table shows the amounts recorded to “Additional paid-in capital” for the nine months ended January 31, 2015 (in thousands):
		Additional
		Paid-in
		Capital
	Balance at April 30, 2014	$	664,602
	Exercise of common stock options	5,116
	Employee stock purchase plan	7,719
	Employee stock-based compensation	25,816
	Withholding tax deduction on restricted stock units	(4,185		)
	Tax effect from stock-based compensation	2,458
	Write-off of employee stock-based compensation related deferred tax assets	(858		)
	Balance at January 31, 2015	$	700,668
Schedule of components of, and the changes in, accumulated other comprehensive income	The following table presents the components of, and the changes in, accumulated other comprehensive income for the nine months ended January 31, 2015 (in thousands):
		Balance at			Other			Amounts			Related Tax			Balance at
		April 30,			Comprehensive			Reclassified out			Effects			January 31,
		2014			Income Before			of Accumulated						2015
					Reclassification			Other
								Comprehensive
								Income
	Accumulated translation gains	$	2,406		$	165		$	—		$	(58	)	$	2,513
	Accumulated unrealized gains (losses) on available-for-sale securities, net	(28		)	35			(1		)	(12		)	(6		)
	Total accumulated other comprehensive income	$	2,378		$	200		$	(1	)	$	(70	)	$	2,507
Schedule of amounts reclassified out of Accumulated Other Comprehensive Income into the Condensed Consolidated Statements of Income and the associated presentation location
	The following table sets forth the amounts reclassified out of Accumulated Other Comprehensive Income into the Condensed Consolidated Statements of Income and the associated presentation location, for the periods indicated (in thousands):
				Three Months Ended						Nine Months Ended
	Comprehensive Income			January 31,						January 31,
	Components	Location		2015			2014			2015			2014
	Accumulated translation gains	Other income, net		$	—		$	(1,023	)	$	—		$	(1,023	)
	Accumulated unrealized gains (losses) on available-for-sale securities, net
		Other income, net		—			—			(1		)	(1,641		)
		Total amounts reclassified out of Accumulated Other Comprehensive Income		$			$	(1,023	)	$	(1	)	$	(2,664	)

Income_Taxes_Tables

Income Taxes (Tables)	9 Months Ended
	Jan. 31, 2015
Income Taxes
Schedule of operating results for the period	The Company reported the following operating results for the periods presented (in thousands):
		Three Months Ended						Nine Months Ended
		January 31,						January 31,
		2015			2014			2015			2014
	Income before income taxes	$	10,805		$	42,256		$	75,103		$	86,678
	Provision for (benefit from) income taxes	$	(3,218	)	$	11,696		$	(12,291	)	$	6,754
	Effective income tax rate	(29.8		)%	27.7		%	(16.4		)%	7.8		%

Related_Party_Transactions_Tab

Related Party Transactions (Tables)	9 Months Ended
	Jan. 31, 2015
Related Party Transactions
Schedule of related party transactions and balances	The following table presents the amounts paid for services provided by related parties and the balances payable for the periods indicated (in thousands):
			Three Months Ended				Nine Months Ended
	Related		January 31,				January 31,
	Party	Description	2015		2014		2015		2014
	VisEra	Purchases of color filter and other manufacturing services	$	25,945	$	22,191	$	77,620	$	93,422
		Rent and other services	$	—	$	—	$	—	$	3
		Balances payable at period end, net	$	18,116	$	23,066	$	18,116	$	23,066
	WLCSP	Purchases of packaging services	$	8,358	$	393	$	19,354	$	436
		Balances payable at period end, net	$	4,376	$	223	$	4,376	$	223

ShortTerm_Investments_Details

Short-Term Investments (Details) (USD $)	Jan. 31, 2015	Apr. 30, 2014
In Thousands, unless otherwise specified
Available-for-sale securities
Amortized Cost	$204,635	$153,034
Gross Unrealized Gains	17	7
Gross Unrealized Losses	-26	-48
Fair Value	204,626	152,993
Contractual maturity dates
Contractual maturity dates, less than one year	201,569	142,758
Contractual maturity dates, one to two years	3,057	10,235
Fair Value	204,626	152,993
Municipal Bonds [Member]
Available-for-sale securities
Amortized Cost	9,205	6,168
Gross Unrealized Gains		1
Gross Unrealized Losses	-3	-2
Fair Value	9,202	6,167
Contractual maturity dates
Fair Value	9,202	6,167
U S Government Agencies Shortterm Debt Securities [Member]
Available-for-sale securities
Amortized Cost	26,652
Gross Unrealized Gains	4
Fair Value	26,656
Contractual maturity dates
Fair Value	26,656
Corporate Debt Securities Or Commercial Paper [Member]
Available-for-sale securities
Amortized Cost	168,778	146,866
Gross Unrealized Gains	13	6
Gross Unrealized Losses	-23	-46
Fair Value	168,768	146,826
Contractual maturity dates
Fair Value	$168,768	$146,826

Supplemental_Balance_Sheet_Acc2

Supplemental Balance Sheet Account Information (in thousands) (Details) (USD $)	Jan. 31, 2015	Apr. 30, 2014	Jan. 31, 2014	Apr. 30, 2013
In Thousands, unless otherwise specified
Cash and cash equivalents:
Cash	$231,640	$195,141
Money market funds, commercial paper and U.S. government bonds	76,521	102,811
Cash and cash equivalents	308,161	297,952	308,927	190,171
Accounts receivable, net:
Accounts receivable	144,758	176,576
Less: Allowance for doubtful accounts	-886	-998
Allowance for sales returns	-2,166	-3,106
Accounts receivable, net	141,706	172,472
Inventories:
Work in progress	173,686	107,621
Finished goods	192,693	163,314
Inventories	366,379	270,935
Prepaid expenses and other current assets:
Prepaid expenses	5,109	4,285
Deposits and other	331	1,284
Interest receivable	1,033	1,007
Prepaid expenses and other current assets	6,473	6,576
Property, plant and equipment, net:
Property, plant and equipment, gross	260,868	261,102
Less: Accumulated depreciation and amortization	-112,352	-107,310
Property, plant and equipment, net	148,516	153,792
Other long-term assets:
Deferred income tax assets - non-current	1,096	528
Land-use rights	2,137	2,180
Other long-term assets	21,961	29,821
Total other long-term assets	25,194	32,529
Accrued expenses and other current liabilities:
Deferred tax liabilities - current	144	144
Employee compensation	12,677	15,176
Third party commissions	511	380
Professional services	2,574	2,270
Noncancelable purchase commitments	729	647
Rebates	1,896	1,511
Other	10,052	11,831
Accrued expenses and other current liabilities	28,583	31,959
Other long-term liabilities:
Interest rate swap	2,341	2,980
Deferred tax liabilities - non-current	12,992	3,731
Other	6,520	5,107
Other long-term liabilities	21,853	11,818
Land [Member]
Property, plant and equipment, net:
Property, plant and equipment, gross	13,000	13,000
Building [Member]
Property, plant and equipment, net:
Property, plant and equipment, gross	82,623	82,547
Building And Building Improvements [Member]
Property, plant and equipment, net:
Property, plant and equipment, gross	29,318	29,123
Machinery And Equipment [Member]
Property, plant and equipment, net:
Property, plant and equipment, gross	120,046	119,762
Furniture And Fixtures [Member]
Property, plant and equipment, net:
Property, plant and equipment, gross	5,030	5,002
Software [Member]
Property, plant and equipment, net:
Property, plant and equipment, gross	8,853	8,774
Construction In Progress [Member]
Property, plant and equipment, net:
Property, plant and equipment, gross	$1,998	$2,894

Longterm_Investments_Details

Long-term Investments (Details) (USD $)	3 Months Ended		9 Months Ended		1 Months Ended	3 Months Ended	1 Months Ended					3 Months Ended		9 Months Ended		1 Months Ended		3 Months Ended
	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2015	Jan. 31, 2014	Apr. 30, 2003	Jul. 31, 2013	Apr. 30, 2014	Jun. 30, 2011	Sep. 30, 2010	31-May-10	31-May-07	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Jun. 30, 2010	Dec. 31, 2009	Oct. 31, 2013	Feb. 29, 2012	Mar. 31, 2014	Apr. 30, 2010	Nov. 30, 2009
Long-term investment disclosures
Long-term investments	$145,310,000		$145,310,000				$154,409,000
Shares outstanding	58,056,000		58,056,000				56,082,000
Net cash proceeds from sale of shares				15,066,000
Gain on the sale of shares				23,802,000
Cumulative translation adjustment reclassified from accumulated other comprehensive income		665,000		665,000
Equity income	1,279,000	837,000	3,248,000	3,264,000
Equity income (losses)			7,461,000	17,865,000
Operating data:
Undistributed earnings of investees	56,431,000		56,431,000				66,772,000
Gain on sale of investment				1,990,000
China W L C S P Limited [Member]
Long-term investment disclosures
Shares outstanding	226,700,000		226,700,000							180,000,000
Xin Tec Inc [Member]
Long-term investment disclosures
Long-term investments	4,661,000		4,661,000				4,661,000
Purchase of long-term investment					2,800,000
Ownership percentage	4.12%		4.12%
Beneficial ownership percentage	11.80%		11.80%
Phostek Inc [Member]
Long-term investment disclosures
Long-term investments																			2,000,000
Phostek Inc [Member] | Other Income [Member]
Long-term investment disclosures
Impairment charge						2,000,000
Vis Era Technologies Company Limited [Member]
Long-term investment disclosures
Long-term investments	103,402,000		103,402,000				115,943,000
Dividend payments received from investee			17,101,000
Equity income (losses)	680,000	-331,000	4,560,000	10,079,000
Net effect on Cost of revenues, after the elimination of unrealized intercompany profits	-81,000	4,220,000	4,213,000	16,378,000
Operating data:
Revenues	28,998,000	24,236,000	86,002,000	103,500,000
Gross profit	5,962,000	13,147,000	21,240,000	46,866,000
Income from operations	3,746,000	10,567,000	14,328,000	38,953,000
Net income (loss)	-165,000	8,588,000	8,574,000	33,328,000
Vis Era Technologies Company Limited [Member] | Camera Cube Production Operations [Member]
Long-term investment disclosures
Post-acquisition gain							3,100,000
Reduction in consideration for production operations from VisEra							4,500,000
Equity method elimination							1,400,000
Consideration for production operations from VisEra								42,900,000
Consideration payable							4,500,000													9,000,000
Final payment for acquisition of production operation							4,500,000
Vis Era Holding Company [Member]
Long-term investment disclosures
Percentage of equity ownership	49.10%		49.10%
Vis Era Holding Company [Member] | Xin Tec Inc [Member]
Long-term investment disclosures
Ownership percentage	15.63%		15.63%
China W L C S P Limited [Member]
Long-term investment disclosures
Long-term investments	37,247,000		37,247,000				33,805,000
Percentage of equity ownership	13.30%		13.30%						18.70%		20.00%										19.70%
Ownership interest in outstanding shares (in shares)	30,300,000		30,300,000							35,400,000
Number of shares issued		37,200,000							9,500,000
IPO price (in dollars per share)		$3.14		$3.14
Number of shares sold as selling shareholder in initial public offering		5,100,000
Net cash proceeds from sale of shares		15,100,000
Cumulative translation adjustment reclassified from accumulated other comprehensive income		1,000,000
Dividend payments received from investee			726,000	830,000
Equity income	1,279,000	837,000	3,248,000	3,264,000
Investment acquired (in shares)											4,500,000
Purchase amount of equity method investment											9,000,000
Income distribution										0
Operating data:
Revenues												32,022,000	20,111,000	78,082,000	58,651,000
Gross profit												14,064,000	11,522,000	40,428,000	32,176,000
Income from operations												7,125,000	6,415,000	21,928,000	21,712,000
Net income (loss)												9,589,000	6,474,000	24,333,000	18,736,000
China W L C S P Limited [Member] | Change In Interest Gain [Member]
Long-term investment disclosures
Gain on the sale of shares		14,100,000
China W L C S P Limited [Member] | Gain From Share Sale [Member]
Long-term investment disclosures
Gain on the sale of shares		9,700,000
China W L C S P Limited [Member] | Other Income [Member]
Long-term investment disclosures
Gain on the sale of shares		23,800,000
Im Pac Technology Company Limited [Member]
Long-term investment disclosures
Percentage of equity ownership																						25.70%
Tong Hsing Electronic Industries Limited [Member]
Long-term investment disclosures
Investment acquired (in shares)								115,481								95,570	996,250
Percentage of equity ownership																	0.80%	0.70%
Operating data:
Additional contributions to other investment								421,000								282,000
Tong Hsing Electronic Industries Limited [Member] | Other Income [Member]
Operating data:
Gain on sale of investment																		$2,000,000

Goodwill_and_Intangible_Assets2

Goodwill and Intangible Assets (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2015	Jan. 31, 2014	Apr. 30, 2014
Change to carrying value of goodwill
Beginning balance					$10,227
Ending balance	10,227	10,227	10,227	10,227	10,227
Intangible assets
Finite-lived intangible assets, Cost	138,906		138,906		138,906
Finite-lived intangible assets, Accumulated Amortization	83,146		83,146		72,689
Finite-lived intangible assets, Net Book Value	55,760		55,760		66,217
Expected future annual amortization of intangible assets
2015	3,473		3,473
2016	13,753		13,753
2017	13,627		13,627
2018	12,546		12,546
2019	3,234		3,234
Thereafter	9,127		9,127
Total	55,760		55,760		66,217
Acquired Patent Portfolio [Member]
Intangible assets
Finite-lived intangible assets, Cost	65,000		65,000		65,000
Finite-lived intangible assets, Accumulated Amortization	35,595		35,595		28,631
Finite-lived intangible assets, Net Book Value	29,405		29,405		36,369
Amortization of intangible assets
Amortization of intangibles	2,321	2,321	6,964	6,964
Expected future annual amortization of intangible assets
Total	29,405		29,405		36,369
Developed Technology Rights [Member]
Intangible assets
Finite-lived intangible assets, Cost	36,100		36,100		36,100
Finite-lived intangible assets, Accumulated Amortization	29,447		29,447		27,980
Finite-lived intangible assets, Net Book Value	6,653		6,653		8,120
Expected future annual amortization of intangible assets
Total	6,653		6,653		8,120
Patents And Licenses [Member]
Intangible assets
Finite-lived intangible assets, Cost	36,066		36,066		36,066
Finite-lived intangible assets, Accumulated Amortization	16,438		16,438		14,438
Finite-lived intangible assets, Net Book Value	19,628		19,628		21,628
Expected future annual amortization of intangible assets
Total	19,628		19,628		21,628
Trademarks And Trade Names [Member]
Intangible assets
Finite-lived intangible assets, Cost	1,400		1,400		1,400
Finite-lived intangible assets, Accumulated Amortization	1,400		1,400		1,400
Customer Relationships [Member]
Intangible assets
Finite-lived intangible assets, Cost	340		340		340
Finite-lived intangible assets, Accumulated Amortization	266		266		240
Finite-lived intangible assets, Net Book Value	74		74		100
Expected future annual amortization of intangible assets
Total	74		74		100
Amortization Of Finite Lived Intangibles Excluding Acquired Patent Portfolio [Member]
Amortization of intangible assets
Amortization of intangibles	$1,151	$584	$3,493	$2,016

Borrowing_Arrangements_and_Rel2

Borrowing Arrangements and Related Derivative Instruments (Details)

0 Months Ended

3 Months Ended

9 Months Ended

9 Months Ended

Mar. 16, 2007

Jan. 31, 2015

Apr. 30, 2014

Jan. 31, 2015

Apr. 30, 2014

Jan. 31, 2015

Jan. 31, 2014

Jan. 31, 2015

Jan. 31, 2014

Jan. 31, 2015

Apr. 30, 2014

Mar. 16, 2007

Jan. 31, 2015

Jan. 31, 2015

Apr. 30, 2014

Jan. 31, 2015

Jan. 31, 2015

building

USD ($)

USD ($)

Other Noncurrent Liabilities [Member]

Other Noncurrent Liabilities [Member]

Other Income [Member]

Other Income [Member]

Other Income [Member]

Other Income [Member]

Mortgage loan [Member]

Mortgage loan [Member]

Mortgage loan [Member]

Mortgage loan [Member]

Construction Loans [Member]

Construction Loans [Member]

Construction Loans [Member]

Construction Loans [Member]

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

London Interbank Offered Rate L I B O R [Member]

USD ($)

USD ($)

Subsidiaries [Member]

Subsidiaries [Member]

USD ($)

CNY

Borrowing arrangements

Long term debt

$32,199,000

$35,832,000

$23,237,000

$23,653,000

$8,962,000

$12,179,000

Less: amount due within one year

-7,071,000

-3,802,000

Non-current portion of long-term debt

25,128,000

32,030,000

Aggregate debt maturities

2015

139,000

139,000

2016

7,071,000

553,000

6,518,000

2017

24,989,000

22,545,000

2,444,000

Total

32,199,000

35,832,000

23,237,000

23,653,000

8,962,000

12,179,000

Number of buildings purchased against Loan and Security Agreement with a domestic bank

4

Aggregate principal amount

27,900,000

Reference rate of debt

LIBOR

Basis points added to reference rate of debt (as a percent)

0.90%

Interest rate on debt (as a percent)

1.10%

1.10%

5.90%

Interest rates swap period

10 years

Stated interest rate on debt (as a percent)

5.30%

Effective interest rate on debt (as a percent)

6.20%

Amount outstanding under line of credit facility

9,000,000

55,000,000

Location of amounts recognized in Consolidated Statements of Income and amount of gains (losses):

Gain (loss) on interest rate swap recorded in other income (expense), net

185,000

320,000

639,000

933,000

Location of amounts on Condensed Consolidated Balance Sheets and fair values:

Interest rate swap recorded in Other long-term liabilities

$2,341,000

$2,980,000

$2,341,000

$2,980,000

Net_Income_Per_Share_Details

Net Income Per Share (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Share data, unless otherwise specified	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2015	Jan. 31, 2014
Net Income Per Share
Antidilutive common stock subject to outstanding options (in shares)	508,000	2,513,000	661,000	2,513,000
Basic Numerator:
Net income	$14,023	$30,560	$87,394	$79,924
Basic Denominator:
Weighted average common shares for net income per share	57,948,000	55,913,000	57,383,000	55,369,000
Basic net income per share	$0.24	$0.55	$1.52	$1.44
Diluted Numerator:
Net income	$14,023	$30,560	$87,394	$79,924
Diluted Denominator:
Denominator for basic net income per share	57,948,000	55,913,000	57,383,000	55,369,000
Weighted average effect of dilutive securities:
Stock options, restricted stock units and employee stock purchase plan shares	2,186,000	273,000	1,855,000	1,103,000
Weighted average common shares for diluted net income per share	60,134,000	56,186,000	59,238,000	56,472,000
Diluted net income per share	$0.23	$0.54	$1.48	$1.42

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (USD $)	Jan. 31, 2015	Apr. 30, 2014
Financial assets and liabilities measured at fair value on a recurring basis
Interest rate swap	($2,341,000)	($2,980,000)
China W L C S P Limited [Member]
Financial assets and liabilities measured at fair value on a recurring basis
Closing stock price (in dollars per share)	$8.60
Fair Value Inputs Level1 [Member] | China W L C S P Limited [Member]
Financial assets and liabilities measured at fair value on a recurring basis
Fair value of equity method investment	260,200,000
Fair Value Measurements Recurring [Member] | Estimate Of Fair Value Fair Value Disclosure [Member]
Financial assets and liabilities measured at fair value on a recurring basis
Cash equivalents	76,521,000	102,812,000
Short-term investments	204,626,000	152,993,000
Total assets	281,147,000	255,805,000
Interest rate swap	-2,341,000	-2,980,000
Total liabilities	-2,341,000	-2,980,000
Fair Value Measurements Recurring [Member] | Estimate Of Fair Value Fair Value Disclosure [Member] | Money Market Funds [Member]
Financial assets and liabilities measured at fair value on a recurring basis
Total assets	17,005,000	57,207,000
Fair Value Measurements Recurring [Member] | Estimate Of Fair Value Fair Value Disclosure [Member] | U S Government Corporations And Agencies Securities [Member]
Financial assets and liabilities measured at fair value on a recurring basis
Total assets	46,646,000	17,834,000
Fair Value Measurements Recurring [Member] | Estimate Of Fair Value Fair Value Disclosure [Member] | Corporate Debt Securities Or Commercial Paper [Member]
Financial assets and liabilities measured at fair value on a recurring basis
Total assets	217,496,000	180,764,000
Fair Value Measurements Recurring [Member] | Fair Value Inputs Level1 [Member]
Financial assets and liabilities measured at fair value on a recurring basis
Cash equivalents	17,005,000	57,207,000
Total assets	17,005,000	57,207,000
Fair Value Measurements Recurring [Member] | Fair Value Inputs Level1 [Member] | Money Market Funds [Member]
Financial assets and liabilities measured at fair value on a recurring basis
Total assets	17,005,000	57,207,000
Fair Value Measurements Recurring [Member] | Fair Value Inputs Level2 [Member]
Financial assets and liabilities measured at fair value on a recurring basis
Cash equivalents	59,516,000	45,605,000
Short-term investments	204,626,000	152,993,000
Total assets	264,142,000	198,598,000
Interest rate swap	-2,341,000	-2,980,000
Total liabilities	-2,341,000	-2,980,000
Fair Value Measurements Recurring [Member] | Fair Value Inputs Level2 [Member] | U S Government Corporations And Agencies Securities [Member]
Financial assets and liabilities measured at fair value on a recurring basis
Total assets	46,646,000	17,834,000
Fair Value Measurements Recurring [Member] | Fair Value Inputs Level2 [Member] | Corporate Debt Securities Or Commercial Paper [Member]
Financial assets and liabilities measured at fair value on a recurring basis
Total assets	$217,496,000	$180,764,000

Segment_and_Geographic_Informa2

Segment and Geographic Information (Details) (Sales [Member])	3 Months Ended		9 Months Ended
	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2015	Jan. 31, 2014
Geographical segment information
Revenues by customer segment (as a percent)	100.00%	100.00%	100.00%	100.00%
O E Ms And V A Rs [Member]
Geographical segment information
Revenues by customer segment (as a percent)	74.40%	80.30%	75.00%	82.10%
Distributors [Member]
Geographical segment information
Revenues by customer segment (as a percent)	25.60%	19.70%	25.00%	17.90%

Segment_and_Geographic_Informa3

Segment and Geographic Information (Details 2) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2015	Jan. 31, 2014	Apr. 30, 2014
Geographical segment information
Revenues	$292,341	$352,023	$1,092,922	$1,122,960
Long-lived assets	317,924		317,924		340,202
China [Member]
Geographical segment information
Revenues	223,462	259,935	879,521	844,764
Long-lived assets	156,411		156,411		162,207
Japan [Member]
Geographical segment information
Revenues	19,523	33,006	66,892	76,776
Singapore
Geographical segment information
Revenues	15,119	6,325	25,965	11,181
Taiwan [Member]
Geographical segment information
Long-lived assets	112,297		112,297		126,820
South Korea [Member]
Geographical segment information
Revenues	9,969	36,466	56,460	140,227
United States [Member]
Geographical segment information
Revenues	4,579	1,146	8,947	3,907
Long-lived assets	48,391		48,391		50,552
Other Geographical Segment [Member]
Geographical segment information
Revenues	19,689	15,145	55,137	46,105
Long-lived assets	$825		$825		$623

Supplemental_Financial_Informa2

Supplemental Financial Information (Details) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Jan. 31, 2014
Additional Paid-in Capital
Tax effect from stock-based compensation	$2,458	$3,926
Additional Paid In Capital [Member]
Additional Paid-in Capital
Balance	664,602
Exercise of common stock options	5,116
Employee stock purchase plan	7,719
Employee stock-based compensation	25,816
Withholding tax deduction on restricted stock units	-4,185
Tax effect from stock-based compensation	2,458
Write-off of employee stock-based compensation related deferred tax assets	-858
Balance	$700,668

Supplemental_Financial_Informa3

Supplemental Financial Information (Details 2) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Apr. 30, 2014
Changes in accumulated other comprehensive income
Balance at the beginning of the period		$2,378
Balance at the end of the period	2,507	2,378
Accumulated Translation Gains [Member]
Changes in accumulated other comprehensive income
Balance at the beginning of the period	2,406
Other Comprehensive Income Before Reclassification	165
Related tax effects	-58
Balance at the end of the period	2,513
Accumulated unrealized gains (losses) on available-for-sale securities, net [Member]
Changes in accumulated other comprehensive income
Balance at the beginning of the period	-28
Other Comprehensive Income Before Reclassification	35
Amounts Reclassified out of Accumulated Other Comprehensive Income	-1
Related tax effects	-12
Balance at the end of the period	-6
Accumulated Other Comprehensive Income [Member]
Changes in accumulated other comprehensive income
Balance at the beginning of the period	2,378
Other Comprehensive Income Before Reclassification	200
Amounts Reclassified out of Accumulated Other Comprehensive Income	-1
Related tax effects	-70
Balance at the end of the period	$2,507

Supplemental_Financial_Informa4

Supplemental Financial Information (Details 3) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2015	Jan. 31, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other income, net	($324)	($24,038)	($1,588)	($25,206)
Reclassification Out Of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total amounts reclassified out of Accumulated Other Comprehensive Income		-1,023	-1	-2,664
Reclassification Out Of Accumulated Other Comprehensive Income [Member] | Accumulated Translation Gains [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other income, net		-1,023		-1,023
Reclassification Out Of Accumulated Other Comprehensive Income [Member] | Accumulated unrealized gains (losses) on available-for-sale securities, net [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other income, net			($1)	($1,641)

Income_Taxes_Details

Income Taxes (Details) (USD $)	3 Months Ended		9 Months Ended
	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2015	Jan. 31, 2014
Income Taxes
Income before income taxes	$10,805,000	$42,256,000	$75,103,000	$86,678,000
Provision for (benefit from) income taxes	-3,218,000	11,696,000	-12,291,000	6,754,000
Effective income tax rate (as a percent)	-29.80%	27.70%	-16.40%	7.80%
Reduction in unrecognized tax benefits due to settlement with taxing authority in a foreign jurisdiction	5,400,000
Amount of benefit from income taxes	2,900,000
Amount of additional interest accrued by the Company related to the unrecognized tax benefits	359,000
Anticipated decrease in gross unrecognized tax benefits due to the lapse of the applicable statutes of limitations in certain foreign jurisdictions over the next 12 months	$5,300,000		$5,300,000

Commitments_and_Contingencies_

Commitments and Contingencies (Details) (USD $)	Jul. 31, 2014	Apr. 30, 2014
In Millions, unless otherwise specified
Powerchip Technology Corporation [Member]
Commitments
Deposit required for prepaid wafer credit	$1
Omni Vision Technologies Shanghai Company Limited [Member]
Commitments
Registered capital requirement	27	12
Remaining capital requirement to be contributed	$15

Commitments_and_Contingencies_1

Commitments and Contingencies (Details 2) (USD $)	9 Months Ended	0 Months Ended
	Jan. 31, 2015	Aug. 09, 2012	Nov. 22, 2011	Dec. 06, 2010	Oct. 26, 2011	10-May-12	Mar. 21, 2012	Nov. 15, 2011
		patent	patent	patent	item	complaint	complaint	complaint
					director
Litigation
Payment for litigation settlement	$12,500,000
Recoverable insurance proceeds	12,500,000
Litigation settlement accrual	$12,500,000
Patent Infringement [Member]
Litigation
Number of patents allegedly infringed		3	5	6
Federal Securities Laws Violation [Member]
Litigation
Number of executives against whom case has been filed					3
Number of Directors against whom case has been filed					1
Shareholder Derivative Actions [Member]
Litigation
Number of shareholder derivative complaints						5	4	3

Related_Party_Transactions_Det

Related Party Transactions (Details) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Jan. 31, 2014	Jan. 31, 2015	Jan. 31, 2014
Vis Era Technologies Company Limited [Member]
Related Party Transactions
Purchases of services	$25,945	$22,191	$77,620	$93,422
Rent and other services				3
Balances payable at period end, net	18,116	23,066	18,116	23,066
China W L C S P Limited [Member]
Related Party Transactions
Purchases of services	8,358	393	19,354	436
Balances payable at period end, net	$4,376	$223	$4,376	$223