Marvell Technology 10-K 26 Mar 15 2015 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
In Millions, unless otherwise specified	Jan. 31, 2015	Mar. 19, 2015	Aug. 01, 2014
Document Type	10-K
Amendment Flag	FALSE
Document Period End Date	31-Jan-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	FY
Trading Symbol	MRVL
Entity Registrant Name	MARVELL TECHNOLOGY GROUP LTD
Entity Central Index Key	1058057
Current Fiscal Year End Date	-30
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		515
Entity Public Float			$4,926

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	Jan. 31, 2015	Feb. 01, 2014
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$1,210,977	$965,750
Short-term investments	1,318,578	1,003,655
Accounts receivable, net of provision for sales returns and allowances of $2,112 and $2,294 in fiscal 2015 and 2014, respectively	420,955	453,496
Inventories	308,162	347,861
Prepaid expenses and other current assets	68,140	56,952
Deferred income taxes	17,228	11,506
Total current assets	3,344,040	2,839,220
Property and equipment, net	340,639	356,165
Long-term investments	10,226	16,279
Goodwill	2,029,945	2,029,945
Acquired intangible assets, net	30,698	49,035
Other non-current assets	128,839	160,366
Total assets	5,884,387	5,451,010
Current liabilities:
Accounts payable	282,899	316,389
Accrued liabilities	131,388	161,762
Accrued employee compensation	154,969	111,408
Deferred income	68,120	61,747
Total current liabilities	637,376	651,306
Non-current income taxes payable	68,729	81,325
Other non-current liabilities	32,193	42,469
Total liabilities	738,298	775,100
Commitments and contingencies (Note 10)
Shareholders' equity:
Preferred stock, $0.002 par value; 8,000 shares authorized; no shares issued and outstanding
Common stock, $0.002 par value; 992,000 shares authorized; 515,037 and 502,405 shares issued and outstanding in fiscal 2015 and 2014, respectively	1,030	1,005
Additional paid-in capital	3,099,548	2,941,650
Accumulated other comprehensive income	308	597
Retained earnings	2,045,203	1,732,658
Total shareholders' equity	5,146,089	4,675,910
Total liabilities and shareholders' equity	$5,884,387	$5,451,010

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)	Jan. 31, 2015	Feb. 01, 2014
In Thousands, except Per Share data, unless otherwise specified
Accounts receivable, provision for sales return and allowances	$2,112	$2,294
Preferred stock, par value	$0.00	$0.00
Preferred stock, shares authorized	8,000	8,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$0.00	$0.00
Common stock, shares authorized	992,000	992,000
Common stock, shares issued	515,037	502,405
Common stock, shares outstanding	515,037	502,405

CONSOLIDATED_STATEMENTS_OF_OPE

CONSOLIDATED STATEMENTS OF OPERATIONS (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013
Net revenue	$3,706,963	$3,404,400	$3,168,630
Operating costs and expenses:
Cost of goods sold	1,843,706	1,663,730	1,493,497
Research and development	1,164,059	1,156,885	1,057,445
Selling and marketing	143,952	152,698	161,817
General and administrative	130,030	106,471	108,514
Amortization and write-off of acquired intangible assets	16,397	43,925	52,700
Total operating costs and expenses	3,298,144	3,123,709	2,873,973
Operating income	408,819	280,691	294,657
Interest and other income, net	23,334	25,566	15,533
Income before income taxes	432,153	306,257	310,190
Provision (benefit) for income taxes	-3,193	-9,063	3,605
Net income	$435,346	$315,320	$306,585
Net income per share:
Basic	$0.85	$0.64	$0.55
Diluted	$0.84	$0.63	$0.54
Weighted average shares:
Basic	511,089	496,518	555,310
Diluted	520,760	504,413	563,123
Cash dividends declared per share	$0.24	$0.24	$0.18

CONSOLIDATED_STATEMENTS_OF_COM

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013
Net income	$435,346	$315,320	$306,585
Other comprehensive income (loss), net of tax:
Net change in unrealized gain (loss) on marketable securities	1,234	-208	-960
Net change in unrealized gain (loss) on auction rate securities	597	-190	-1,396
Net change in unrealized gain (loss) on cash flow hedges	-2,120	-153	2,728
Net current-period other comprehensive income (loss)	-289	-551	372
Comprehensive income	$435,057	$314,769	$306,957

CONSOLIDATED_STATEMENTS_OF_SHA

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (USD $)	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income	Retained Earnings
In Thousands
Beginning Balance at Jan. 28, 2012	$5,014,018	$1,167	$3,683,112	$776	$1,328,963
Beginning Balance (in shares) at Jan. 28, 2012		583,671
Shares issued pursuant to stock options and awards, net (in shares)		8,090
Shares issued pursuant to stock options and awards, net	28,411	17	28,394
Issuance of common stock under the employee stock purchase plan (in shares)		7,578
Issuance of common stock under the employee stock purchase plan	66,426	15	66,411
Share-based compensation	126,683		126,683
Tax (deficiency) benefit from employee stock transactions	-52		-52
Repurchase of common stock (In Shares)		-91,001
Repurchase of common stock	-959,087	-182	-958,905
Cash dividends declared and paid (cumulatively $0.24, $0.24 and $0.18 per share in fiscal 2015, 2014 and 2013 respectively)	-98,761				-98,761
Net income	306,585				306,585
Other comprehensive income (loss)	372			372
Ending Balance at Feb. 02, 2013	4,484,595	1,017	2,945,643	1,148	1,536,787
Ending Balance (in shares) at Feb. 02, 2013		508,338
Shares issued pursuant to stock options and awards, net (in shares)		17,479
Shares issued pursuant to stock options and awards, net	122,427	35	122,392
Issuance of common stock under the employee stock purchase plan (in shares)		9,701
Issuance of common stock under the employee stock purchase plan	71,663	19	71,644
Share-based compensation	156,126		156,126
Tax (deficiency) benefit from employee stock transactions	-88		-88
Repurchase of common stock (In Shares)		-33,113
Repurchase of common stock	-354,133	-66	-354,067
Cash dividends declared and paid (cumulatively $0.24, $0.24 and $0.18 per share in fiscal 2015, 2014 and 2013 respectively)	-119,449				-119,449
Net income	315,320				315,320
Other comprehensive income (loss)	-551			-551
Ending Balance at Feb. 01, 2014	4,675,910	1,005	2,941,650	597	1,732,658
Ending Balance (in shares) at Feb. 01, 2014		502,405
Shares issued pursuant to stock options and awards, net (in shares)		8,012
Shares issued pursuant to stock options and awards, net	11,545	16	11,529
Issuance of common stock under the employee stock purchase plan (in shares)		9,690
Issuance of common stock under the employee stock purchase plan	74,318	19	74,299
Share-based compensation	137,001		137,001
Tax (deficiency) benefit from employee stock transactions	21		21
Repurchase of common stock (In Shares)		-5,070
Repurchase of common stock	-64,962	-10	-64,952
Cash dividends declared and paid (cumulatively $0.24, $0.24 and $0.18 per share in fiscal 2015, 2014 and 2013 respectively)	-122,801				-122,801
Net income	435,346				435,346
Other comprehensive income (loss)	-289			-289
Ending Balance at Jan. 31, 2015	$5,146,089	$1,030	$3,099,548	$308	$2,045,203
Ending Balance (in shares) at Jan. 31, 2015		515,037

CONSOLIDATED_STATEMENTS_OF_SHA1

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (Parenthetical) (USD $)	12 Months Ended
	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013
Cash dividends declared and paid	$0.24	$0.24	$0.18

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013
Cash flows from operating activities:
Net income	$435,346	$315,320	$306,585
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	106,248	102,752	91,028
Share-based compensation	137,246	155,873	127,280
Amortization and write-off of acquired intangible assets	18,337	44,006	52,700
Gain on sale of business		-6,975
Other expense, net	-10,629	8,178	7,392
Excess tax benefits from share-based compensation	-145	-20	-58
Deferred income tax	-12,913	3,919	7,026
Changes in assets and liabilities, net of assets acquired and liabilities assumed in acquisitions:
Accounts receivable	34,165	-123,258	77,025
Inventories	39,454	-97,188	103,102
Prepaid expenses and other assets	5,788	19,458	-6,894
Accounts payable	-43,871	39,791	-24,304
Accrued liabilities and other non-current liabilities	-30,024	-9,627	8,014
Accrued employee compensation	43,561	-5,787	-20,050
Deferred income	6,373	1,597	191
Net cash provided by operating activities	728,936	448,039	729,037
Cash flows from investing activities:
Purchases of available-for-sale securities	-1,128,319	-837,892	-1,543,902
Sales and maturities of available-for-sale securities	826,310	995,039	1,835,655
Investments in privately-held companies	-701	-1,869	-8,750
Proceeds from sale of an investment in a privately-held company	13,220
Cash paid for acquisitions, net		-2,551	-1,000
Proceeds from sale of business		6,306
Purchases of technology licenses	-16,424	-17,647	-35,002
Purchases of property and equipment	-63,030	-66,593	-68,186
Net cash provided by (used in) investing activities	-368,944	74,793	178,815
Cash flows from financing activities:
Repurchase of common stock	-64,962	-376,285	-936,935
Proceeds from employee stock plans	112,357	204,962	104,936
Minimum tax withholding paid on behalf of employees for net share settlement	-26,494	-10,872	-10,099
Dividend payments to shareholders	-122,801	-119,449	-98,761
Payments on technology license obligations	-13,010	-7,411
Excess tax benefits from share-based compensation	145	20	58
Net cash used in financing activities	-114,765	-309,035	-940,801
Net increase (decrease) in cash and cash equivalents	245,227	213,797	-32,949
Cash and cash equivalents at beginning of the year	965,750	751,953	784,902
Cash and cash equivalents at end of the year	1,210,977	965,750	751,953
Supplemental cash flow information:
Cash paid for interest	1,167	1,873	563
Cash paid for income taxes, net	15,727	9,385	16,813
Non-Cash Investing and Financing Activities:
Purchase of intellectual property under license obligations		$8,900	$42,692

The_Company_and_its_Significan

The Company and its Significant Accounting Policies	12 Months Ended
	Jan. 31, 2015
The Company and its Significant Accounting Policies	Note 1 — The Company and its Significant Accounting Policies
	The Company
	Marvell Technology Group Ltd., a Bermuda company (the “Company”), is a leading global semiconductor provider of high-performance application-specific standard products. The Company’s core strength of expertise is the development of complex System-on-a-Chip and System-in-a-Package devices, leveraging its extensive technology portfolio of intellectual property in the areas of analog, mixed-signal, digital signal processing, and embedded and stand alone integrated circuits. The majority of the Company’s product portfolio leverages the ARM technology portfolio. The Company also develops platforms that it defines as integrated hardware along with software that incorporates digital computing technologies designed and configured to provide an optimized computing solution compared to individual components. The Company’s broad product portfolio includes devices for data storage, enterprise-class Ethernet data switching, Ethernet physical-layer transceivers, mobile handsets, connectivity, Internet-of-Things devices and other consumer electronics.
	Basis of Presentation
	The Company’s fiscal year is the 52- or 53-week period ending on the Saturday closest to January 31. In a 52-week year, each fiscal quarter consists of 13 weeks. The additional week in a 53-week year is added to the fourth quarter, making such quarter consist of 14 weeks. Fiscal 2015 and 2014 each had a 52-week period, and fiscal 2013 had a 53-week period.
	Use of Estimates
	The preparation of consolidated financial statements in conformity with generally accepted accounting principles in the United States (“GAAP”) requires management to make estimates, judgments and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, and related disclosure of contingent assets and liabilities. On an ongoing basis, the Company evaluates its estimates, including those related to performance-based compensation, revenue recognition, provisions for sales returns and allowances, inventory excess and obsolescence, investment fair values, goodwill and other intangible assets, restructuring, income taxes, litigation and other contingencies. In addition, the Company uses assumptions when employing the Monte Carlo simulation and Black-Scholes valuation models to calculate the fair value of share-based awards that are granted. Actual results could differ from these estimates, and such differences could affect the results of operations reported in future periods.
	Principles of Consolidation
	The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated. The functional currency of the Company and its subsidiaries is the U.S. dollar.
	Cash and Cash Equivalents
	The Company considers all highly liquid investments with a maturity of three months or less from the date of purchase to be cash equivalents. Cash and cash equivalents consist of cash on deposit with banks, time deposits, U.S. government and agency debt, municipal debt securities, corporate debt securities and money market funds.
	Investments
	The Company’s marketable investments are classified as available-for-sale and are reported at fair value. The Company determines any realized gains or losses on the sale of available-for-sale securities on a specific identification method, and such gains and losses are recorded as a component of interest and other income, net. Unrealized gains and losses of the available-for-sale securities are excluded from earnings and reported as a component of accumulated other comprehensive income. The Company assesses whether an other-than-temporary impairment loss on its available-for-sale securities has occurred due to declines in fair value or other market conditions. Declines in fair value that are considered other-than-temporary are recorded as an impairment of investments in interest and other income, net in the consolidated statements of operations.
	In general, investments with original maturities of greater than 90 days and remaining maturities of less than one year are classified as short-term investments. Investments with maturities beyond one year may also be classified as short-term based on their highly liquid nature and because such investments represent the investment of cash that is available for current operations.
	The Company also has equity investments in privately-held companies. If the Company has the ability to exercise significant influence over the investee, but not control, or if the investee is a partnership type investment, the Company accounts for the investments under the equity method. If the Company does not have the ability to exercise significant influence over the operations of the investee, the Company accounts for the investment under the cost method. Investments in privately-held companies are included in other non-current assets.
	Impairment of Investments
	If a debt security’s market value is below amortized cost and the Company either intends to sell the security or it is more likely than not that the Company will be required to sell the security before its anticipated recovery, the Company records an other-than-temporary impairment charge to interest and other income, net in the consolidated statements of operations.
	Investments in privately-held companies are subject to a periodic impairment review. Investments are considered impaired when the fair value is below the investment’s cost basis and the decline in value is judged to be other-than-temporary. This assessment is based on a qualitative and quantitative analysis, including, but not limited to, the investee’s revenue and earnings trends, available cash and liquidity, and the status of the investee’s products and the related market for such products. During fiscal 2014, the Company recorded a charge of $1.5 million to write down equity investments that were considered to be impaired. There were no such charges recorded in fiscal 2015 and 2013.
	Derivative Financial Instruments
	The Company accounts for its derivative instruments as either assets or liabilities and carries them at fair value. For derivative instruments that hedge the exposure to variability in expected future cash flows and are designated as cash flow hedges, the effective portion of the gain or loss on the derivative instrument is reported as a component of accumulated other comprehensive income in shareholders’ equity and reclassified into earnings in the same period or periods during which the hedged transaction affects earnings. The ineffective portion of the gain or loss on the derivative instrument is recognized in current earnings. To receive hedge accounting treatment, cash flow hedges must be highly effective in offsetting changes to expected future cash flows on hedged transactions. Derivatives that are not designated as hedges must be adjusted to fair value through earnings.
	Concentration of Credit Risk and Significant Customers
	Financial instruments that potentially subject the Company to a significant concentration of credit risk consist principally of cash equivalents, short-term investments and accounts receivable. Cash, cash equivalents and short-term investments balances are maintained with high-quality financial institutions, the composition and maturities of which are regularly monitored by management. The Company believes that the concentration of credit risk in its trade receivables, which consists of a customer base located primarily in the Asia Pacific Region, is substantially mitigated by the Company’s credit evaluation process, relatively short collection terms and the high level of credit worthiness of its customers. The Company performs ongoing credit evaluations of its customers’ financial conditions and limits the amount of credit extended when deemed necessary based upon payment history and the customer’s current credit worthiness, but generally requires no collateral. The Company regularly reviews the allowance for bad debt and doubtful accounts by considering factors such as historical experience, credit quality, age of the accounts receivable balances and current economic conditions that may affect a customer’s ability to pay.
	The Company’s accounts receivable was concentrated with two customers at January 31, 2015, representing 15% and 14% of gross accounts receivable, respectively, and with one customer at February 1, 2014, representing 13% of gross accounts receivable.
	The allowance for doubtful accounts at January 31, 2015 and February 1, 2014 was $1.2 million and $1.3 million, respectively. Please see “Note 1 – The Company and its Significant Accounting Policies – Revenue Recognition” for additional information on sales returns and allowances.
	Historically, a relatively small number of customers have accounted for a significant portion of the Company’s net revenue. Net revenue from one customer was 20%, 24% and 24% for fiscal 2015, 2014 and 2013, respectively. Net revenue from a second customer was 13%, 12% and 10% for fiscal 2015, 2014 and 2013, respectively. In fiscal 2013, net revenue from a third customer was 10%.
	The Company also had net revenue from one distributor representing 11% and 11% for fiscal 2015 and 2013, respectively. No distributors accounted for 10% or greater of total net revenue in fiscal 2014. The Company continuously monitors the creditworthiness of its distributors and believes these distributors’ sales to diverse end customers and to diverse geographies further serve to mitigate the Company’s exposure to credit risk.
	Inventories
	Inventory is stated at the lower of cost or market, cost being determined under the first-in, first-out method. The total carrying value of the Company’s inventory is reduced for any difference between cost and estimated market value of inventory that is determined to be excess, obsolete or unsellable inventory based upon assumptions about future demand and market conditions. If actual future demand for the Company’s products is less than currently forecasted, the Company may be required to write inventory down below the current carrying value. Once the carrying value of inventory is reduced, it is maintained until the product to which it relates to is sold or otherwise disposed of. Shipping and handling costs are classified as a component of cost of goods sold in the consolidated statements of operations.
	Property and Equipment, Net
	Property and equipment, net, are stated at cost less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the assets, which ranges from three to seven years for machinery and equipment, computer software, and furniture and fixtures. Buildings are depreciated over an estimated useful life of 30 years and building improvements are depreciated over estimated useful lives of 15 years. Leasehold improvements are depreciated using the shorter of the remaining lease term or the estimated useful life of the asset.
	Goodwill
	Goodwill is recorded when the consideration paid for a business acquisition exceeds the fair value of net tangible and intangible assets acquired. Goodwill is measured and tested for impairment annually or more frequently if the Company believes indicators of impairment exist. The Company first assesses qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount. If the company concludes that it is more likely than not that the fair value of a reporting unit is less than its carrying amount, then a two-step quantitative impairment test is performed. The first step requires comparing the fair value of the reporting unit to its net book value, including goodwill. As the Company has only one reporting unit, the fair value of the reporting unit is determined by taking the market capitalization of the Company as determined through quoted market prices and adjusted for control premiums and other relevant factors. A potential impairment exists if the fair value of the reporting unit is lower than its net book value. The second step of the process is only performed if a potential impairment exists, and it involves determining the difference between the fair value of the reporting unit’s net assets other than goodwill and the fair value of the reporting unit. If the difference is less than the net book value of goodwill, impairment exists and is recorded. In the event that the Company determines that the value of goodwill has become impaired, the Company will record a charge for the amount of impairment during the fiscal quarter in which the determination is made.
	Long-Lived Assets and Intangible Assets
	The Company assesses the impairment of long-lived assets and intangible assets whenever events or changes in circumstances indicate that the carrying amount of long-lived assets may not be recoverable. The Company estimates the future cash flows, undiscounted and without interest charges, expected to be generated by the assets from its use or eventual disposition. If the sum of the expected future cash flows is less than the carrying amount of those assets, the Company recognizes an impairment loss based on the excess of the carrying amount over the fair value of the assets. Please see “Note 7 – Goodwill and Acquired Intangible Assets” for further details regarding impairment of acquisition-related identified intangible assets.
	Acquisition-related identified intangible assets are amortized on a straight-line basis over their estimated economic lives. In-process research and development (“IPR&D”) is not amortized until the completion of the related development.
	Foreign Currency Transactions
	The functional currency of all of the Company’s non-U.S. operations is the U.S. dollar. Monetary accounts maintained in currencies other than the U.S. dollar are re-measured using the foreign exchange rate at the balance sheet date. Operational accounts and nonmonetary balance sheet accounts are measured and recorded at the rate in effect at the date of the transaction. The effects of foreign currency re-measurement are reported in current operations.
	Revenue Recognition
	The Company recognizes revenue when there is persuasive evidence of an arrangement, delivery has occurred, the fee is fixed or determinable, and collection is reasonably assured.
	Product revenue is generally recognized upon shipment of product to customers, net of accruals for estimated sales returns and rebates. However, some of the Company’s sales are made through distributors under agreements allowing for price protection, shipped from stock pricing adjustment rights, and limited rights of stock rotation on products unsold by the distributors. Although title passes to the distributor upon shipment terms and payment by the Company’s distributors is not contingent on resale of the product, product revenue on sales made through distributors with price protection, shipped from stock pricing adjustment rights and stock rotation rights are deferred until the distributors sell the product to end customers. Deferred revenue less the related cost of the inventories is reported as deferred income. The Company does not believe that there is any significant exposure related to impairment of deferred cost of sales, as its historical returns have been minimal and inventory turnover for its distributors generally ranges from 60 to 90 days. The Company’s sales to direct customers are made primarily pursuant to standard purchase orders for delivery of products.
	A portion of the Company’s net revenue is derived from sales through third-party logistics providers, who maintain warehouses in close proximity to the customer’s facilities. Revenue from sales through these third-party logistics providers is not recognized until the product is pulled from stock by the end customer.
	The provision for estimated sales returns on product sales is recorded in the same period the related revenues are recorded. These estimates are based on historical returns, analysis of credit memo data and other known factors. Actual returns could differ from these estimates. The Company accounts for rebates by recording reductions to revenue for rebates in the same period that the related revenue is recorded. The amount of these reductions is based upon the terms agreed to with the customer.
	Advertising Expense
	Advertising costs are expensed as incurred.
	Share-Based Compensation
	Share-based compensation is measured at the grant date, based on the fair value of the award, and is recognized as expense over the requisite service period. The Company amortizes share-based compensation expense for time-based and market-based awards under the straight-line attribution method over the vesting period, which is generally four years for annual grants to employees and five years for new hire grants. Performance-based awards are amortized using the accelerated method. For stock purchase rights under the stock purchase plan, the company amortized share-based compensation expense ratably over the two-year offering period.
	The Company estimates the fair value of time-based stock option and stock purchase awards on the date of grant using the Black Scholes option-pricing model. The fair value of market-based stock option awards is estimated on the date of grant using a Monte Carlo simulation model. The value of the portion of the awards that is ultimately expected to vest is recognized as expense over the requisite service periods. The Black Scholes and Monte Carlo models incorporate various highly subjective assumptions including expected term of awards, expected future stock price volatility and expected forfeiture rates.
	In developing estimates used to calculate assumptions, the Company establishes the expected term for employee stock options, as well as expected forfeiture rates, based on the historical settlement experience and after giving consideration to vesting schedules. Assumptions for stock option exercises and pre-vesting terminations of stock options were stratified by employee groups with sufficiently distinct behavior patterns. Expected volatility was developed based on equally weighted combination of historical stock price volatility and implied volatility derived from traded options on the Company’s stock in the marketplace. The expected dividend yield is calculated by dividing annualized dividend payments by the closing stock price on the grant date of the option.
	Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from initial estimates. Share-based compensation expense is recorded net of estimated forfeitures such that expense is recorded only for those share-based awards that are expected to vest. Previously recognized expense is reversed for the portion of awards forfeited prior to vesting as and when forfeitures occurred.
	The fair value of each restricted stock unit is estimated based on the market price of the Company’s common shares on the date of grant less the expected dividend yield.
	Comprehensive Income
	Comprehensive income is comprised of net income and unrealized gains and losses, net of tax, on available-for-sale securities, auction rate securities and cash flow hedges. Accumulated other comprehensive income, as presented on the accompanying balance sheets, consists of net unrealized gains and losses on available-for-sale securities, auction rate securities and cash flow hedges, net of tax.
	Accounting for Income Taxes
	The Company recognizes income taxes using an asset and liability approach. This approach requires the recognition of taxes payable or refundable for the current year, and deferred tax liabilities and assets for the future tax consequences of events that have been recognized in the Company’s consolidated financial statements or tax returns. The measurement of current and deferred taxes is based on provisions of the enacted tax law and the effects of future changes in tax laws or rates are not anticipated.
	A valuation allowance must be established for deferred tax assets when it is more likely than not that they will not be realized. Based on the available evidence and judgment, the Company has determined that it is more likely than not that U.S. research credits and certain acquired net operating losses will not be realized and therefore the Company has provided a full valuation allowance against these credits. If there is a change in the Company’s ability to realize its deferred tax assets, then the Company’s tax provision may decrease in the period in which it determines that realization is more likely than not.
	The Company is subject to income tax audits by the respective tax authorities in each jurisdiction in which the Company operates. The Company recognizes the effect of income tax positions only if these positions are more likely than not of being sustained. Recognized income tax positions are measured at the largest amount that is more than 50% likely of being realized. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. The Company records interest and penalties related to unrecognized tax benefits in income tax expense.
	Warranty
	The Company’s products are generally subject to warranty, which provides for the estimated future costs of repair, replacement or customer accommodation upon shipment of the product. The Company’s products carry a standard 90 day warranty, with certain exceptions in which the warranty period can extend to more than one year based on contractual agreements. The warranty accrual is primarily estimated based on historical claims compared to historical revenues and assumes that the Company will have to replace products subject to a claim. From time to time, the Company becomes aware of specific warranty situations, and it records specific accruals to cover these exposures.
	Recent Accounting Pronouncements
	Accounting Pronouncements Recently Adopted
	In July 2013, the Financial Accounting Standards Board (“FASB”) issued an amendment to the accounting guidance related to the financial statement presentation of an unrecognized tax benefit. The guidance requires an unrecognized tax benefit, or a portion of an unrecognized tax benefit, to be presented in the financial statements as a reduction to a deferred tax asset when a net operating loss carryforward, a similar tax loss or a tax credit carryforward is available at the reporting date. The Company adopted this guidance in fiscal 2015 on a prospective basis and presented a portion of its unrecognized tax benefits as a reduction of its deferred tax assets on the face of the consolidated balance sheet as of January 31, 2015. See also “Note 9 — Income Taxes” in the Notes to the Consolidated Financial Statements.”
	Accounting Pronouncements Not Yet Effective
	In April 2014, the FASB issued an amendment to its guidance regarding the reporting requirements of discontinued operations. Under this amended guidance, a discontinued operation is defined as a disposal of a component or group of components that is disposed of or is classified as held for sale and represents a strategic shift that has (or will have) a major effect on an entity’s operations and financial results. In addition, this amendment requires an entity to present, for each comparative period, the assets and liabilities of a disposal group that includes a discontinued operation separately in the asset and liability sections, respectively, of the statement of financial position and additional disclosures about discontinued operations. This amended guidance is effective for annual and interim reporting periods beginning after December 15, 2014. The Company expects this guidance to have an impact on its financial statements only in the event of a future disposition which meets the criteria.
	In May 2014, the FASB issued a new standard on the recognition of revenue from contracts with customers, which will supersede nearly all existing revenue recognition guidance under GAAP. The core principal of the standard is that an entity should recognize revenue when a customer has control of promised goods or services in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. It also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, and assets recognized from costs incurred to obtain or fulfill a contract, including significant judgments and changes in judgments. This standard is effective for annual and interim reporting periods beginning after December 15, 2016 and will be effective for the Company’s first quarter of fiscal 2018. Early adoption is not permitted. The standard allows for either full retrospective or modified retrospective adoption. The Company is evaluating the transition method that will be elected and the potential effects of adoption on its financial statements.

Acquisitions_and_Divestitures

Acquisitions and Divestitures	12 Months Ended
	Jan. 31, 2015
Acquisitions and Divestitures	Note 2 — Acquisitions and Divestitures
	The Company had no acquisitions or divestitures in fiscal 2015.
	Acquisitions
	Fiscal 2014 and 2013. Acquisitions completed by the Company during fiscal 2014 or 2013 were not significant individually or in the aggregate.
	Divestiture
	Fiscal 2014. The Company exited one of its businesses and sold certain assets to an unrelated third party as part of cost reduction efforts related to related restructuring actions in fiscal 2014. See “Note 8 – Restructuring” for further information. The transaction primarily included the sale of intellectual property and equipment with a carrying value of $0.1 million. The Company also wrote off $2.6 million of goodwill allocated to the business based on the relative fair values of the business and the Company’s remaining reporting unit. The buyer also hired the former employees of the business. As part of the transaction, the Company received a license to the intellectual property it sold. It also entered into a separate support services agreement with the buyer to cover an 18-month period. As a result of the sale of this business, the Company recorded a gain of $7.0 million, which is included in interest and other income, net, in the consolidated statement of operations.

Investments

Investments	12 Months Ended
	Jan. 31, 2015
Investments	Note 3 — Investments
	The following tables summarize the Company’s investments (in thousands):
		As of January 31, 2015
		Amortized			Gross			Gross			Estimated
		Cost			Unrealized			Unrealized			Fair Value
					Gains			Losses
	Short-term investments:
	Available-for-sale:
	Corporate debt securities	$	983,008		$	3,872		$	(563	)	$	986,317
	U.S. government and agency debt		178,898			265			(7	)		179,156
	Asset backed securities		91,432			108			(9	)		91,531
	Foreign government and agency debt		28,051			61			(2	)		28,110
	Municipal debt securities		33,421			47			(4	)		33,464
	Total short-term investments		1,314,810			4,353			(585	)		1,318,578
	Long-term investments:
	Available-for-sale:
	Auction rate securities		12,500			—			(2,274	)		10,226
	Total long-term investments		12,500			—			(2,274	)		10,226
	Total investments	$	1,327,310		$	4,353		$	(2,859	)	$	1,328,804
		As of February 1, 2014
		Amortized			Gross			Gross			Estimated
		Cost			Unrealized			Unrealized			Fair Value
					Gains			Losses
	Short-term investments:
	Available-for-sale:
	Corporate debt securities	$	587,095		$	2,789		$	(370	)	$	589,514
	U.S. government and agency debt		301,423			128			(72	)		301,479
	Asset backed securities		76,220			89			(38	)		76,271
	Foreign government and agency debt		20,324			12			(44	)		20,292
	Municipal debt securities		16,059			44			(4	)		16,099
	Total short-term investments		1,001,121			3,062			(528	)		1,003,655
	Long-term investments:
	Available-for-sale:
	Auction rate securities		19,150			—			(2,871	)		16,279
	Total long-term investments		19,150			—			(2,871	)		16,279
	Total investments	$	1,020,271		$	3,062		$	(3,399	)	$	1,019,934
	As of January 31, 2015, the Company’s investment portfolio included auction rate securities with an aggregate par value of $12.5 million. Although these securities have continued to pay interest and show an improvement in the underlying collateralization, there is currently limited trading volume. To estimate the fair value of the auction rate securities, the Company uses a discounted cash flow model based on estimated timing and amount of future interest and principal payments. In developing the cash flow model, the Company considers the credit quality and liquidity of the underlying securities and related issuer, the collateralization of underlying security investments and other considerations. The fair value of the auction rate securities as of January 31, 2015 was $2.3 million less than the par value and was recorded in long-term investments. Based on the Company’s balance of approximately $2.5 billion in cash, cash equivalents and short-term investments, and the fact that the Company continues to generate positive cash flow from operations on a quarterly basis, the Company does not anticipate having to sell these securities below par value and does not have the intent to sell these auction rate securities until recovery. Since the Company considers the impairment to be temporary, the Company recorded the unrealized loss to accumulated other comprehensive income, a component of shareholders’ equity.
	Gross realized gains and gross realized losses on sales of available-for-sales securities are presented in the following table (in thousands):
		Year Ended
		January 31,			February 1,			February 2,
		2015			2014			2013
	Gross realized gains	$	1,618		$	1,567		$	3,557
	Gross realized losses		(169	)		(268	)		(319	)
	Total net realized gains	$	1,449		$	1,299		$	3,238
	The contractual maturities of available-for-sale securities are presented in the following table (in thousands):
		January 31, 2015						February 1, 2014
		Amortized			Estimated			Amortized			Estimated
		Cost			Fair Value			Cost			Fair Value
	Due in one year or less	$	361,108		$	361,396		$	309,543		$	309,861
	Due between one and five years		950,702			954,151			686,062			688,280
	Due over five years		15,500			13,257			24,666			21,793
		$	1,327,310		$	1,328,804		$	1,020,271		$	1,019,934
	For individual securities that have been in a continuous unrealized loss position, the fair value and gross unrealized loss for these securities aggregated by investment category and length of time in an unrealized position are presented in the following tables (in thousands):
		January 31, 2015
		Less than 12 months						12 months or more						Total
		Fair			Unrealized			Fair			Unrealized			Fair		Unrealized
		Value			Loss			Value			Loss			Value		Loss
	Corporate debt securities	$	243,699		$	(558	)	$	2,005		$	(5	)	$	245,704	$	(563	)
	U.S. government and agency debt		32,165			(7	)		—			—			32,165		(7	)
	Asset backed securities		25,053			(9	)		—			—			25,053		(9	)
	Foreign government and agency debt		2,999			(2	)		—			—			2,999		(2	)
	Municipal debt securities		2,845			(4	)		—			—			2,845		(4	)
	Auction rate securities		—			—			10,226			(2,274	)		10,226		(2,274	)
	Total securities	$	306,761		$	(580	)	$	12,231		$	(2,279	)	$	318,992	$	(2,859	)
	February 1, 2014
	Less than 12 months						12 months or more						Total
	Fair			Unrealized			Fair			Unrealized			Fair		Unrealized
	Value			Loss			Value			Loss			Value		Loss
Corporate debt securities	$	110,903		$	(366	)	$	2,105		$	(4	)	$	113,008	$	(370	)
U.S. government and agency debt		93,118			(72	)		—			—			93,118		(72	)
Asset backed securities		18,865			(19	)		1,912			(19	)		20,777		(38	)
Foreign government and agency debt		14,299			(44	)		—			—			14,299		(44	)
Municipal debt securities		723			(4	)		—			—			723		(4	)
Auction rate securities		—			—			16,279			(2,871	)		16,279		(2,871	)
Total securities	$	237,908		$	(505	)	$	20,296		$	(2,894	)	$	258,204	$	(3,399	)

Supplemental_Financial_Informa

Supplemental Financial Information	12 Months Ended
	Jan. 31, 2015
Supplemental Financial Information	Note 4 — Supplemental Financial Information (in thousands)
	Consolidated Balance Sheets
		January 31,			February 1,
		2015			2014
	Cash and cash equivalents:
	Cash	$	864,680		$	694,789
	Cash equivalents:
	Time deposits		213,012			247,958
	U.S. government and agency debt		—			11,999
	Municipal debt securities		—			4,800
	Corporate debt securities		21,999			3,400
	Money market funds		111,286			2,804
	Cash and cash equivalents	$	1,210,977		$	965,750
		January 31,			February 1,
		2015			2014
	Inventories:
	Work-in-process	$	183,869		$	195,495
	Finished goods		124,293			152,366
	Inventories	$	308,162		$	347,861
		January 31,			February 1,
		2015			2014
	Property and equipment, net:
	Machinery and equipment	$	601,961		$	562,038
	Buildings		144,320			144,320
	Computer software		99,312			96,096
	Land		53,373			53,373
	Building improvements		49,753			49,645
	Leasehold improvements		51,434			49,060
	Furniture and fixtures		27,883			27,621
	Construction in progress		6,167			2,911
			1,034,203			985,064
	Less: Accumulated depreciation		(693,564	)		(628,899	)
	Property and equipment, net	$	340,639		$	356,165
	The Company recorded depreciation expense of $78.3 million, $77.2 million and $70.7 million for fiscal 2015, 2014 and 2013, respectively.
		January 31,			February 1,
		2015			2014
	Other non-current assets:
	Technology and other licenses	$	61,217		$	83,521
	Deferred tax assets		22,273			19,282
	Investments in privately-held companies		9,267			14,565
	Prepaid land use rights		13,432			13,744
	Deposits		7,903			12,433
	Other		14,747			16,821
	Other non-current assets	$	128,839		$	160,366
	Amortization of technology and other licenses was $27.9 million, $25.6 million and $20.3 million in fiscal 2015, 2014 and 2013, respectively.
		January 31,			February 1,
		2015			2014
	Accrued liabilities:
	Accrued rebates	$	39,105		$	61,616
	Accrued royalties		24,680			36,568
	Technology license obligations		14,428			18,482
	Accrued legal expense		10,027			14,589
	Other		43,148			30,507
	Accrued liabilities	$	131,388		$	161,762
		January 31,			February 1,
		2015			2014
	Other non-current liabilities:
	Technology license obligations	$	16,468		$	28,959
	Long-term accrued employee compensation		4,610			4,370
	Other		11,115			9,140
	Other non-current liabilities	$	32,193		$	42,469
	Accumulated other comprehensive income:
	The changes in accumulated other comprehensive income by components are presented in the following tables (in thousands):
		Unrealized			Unrealized			Unrealized			Total
Gain		Loss on			Gain
(Loss) on		Auction			(Loss) on
Marketable		Rate			Cash Flow
Securities		Securities			Hedges
Balance at February 1, 2014	$	2,534		$	(2,871	)	$	934		$	597
Other comprehensive income (loss) before reclassifications		2,479			85			(2,338	)		226
Amounts reclassified from accumulated other comprehensive income		(1,245	)		512			218			(515	)
Net current-period other comprehensive income (loss)		1,234			597			(2,120	)		(289	)
Balance at January 31, 2015	$	3,768		$	(2,274	)	$	(1,186	)	$	308
	Unrealized			Unrealized			Unrealized			Total
	Gain			Loss on			Gain
	(Loss) on			Auction			(Loss) on
	Marketable			Rate			Cash Flow
	Securities			Securities			Hedges
Balance at February 2, 2013	$	2,742		$	(2,681	)	$	1,087		$	1,148
Other comprehensive income (loss) before reclassifications		931			(190	)		3,466			4,207
Amounts reclassified from accumulated other comprehensive income		(1,139	)		—			(3,619	)		(4,758	)
Net current-period other comprehensive loss		(208	)		(190	)		(153	)		(551	)
Balance at February 1, 2014	$	2,534		$	(2,871	)	$	934		$	597
The amounts reclassified from accumulated other comprehensive income by components are presented in the following table (in thousands):
	Year Ended
Affected Line Item in the	January 31,			February 1,			February 2,
Statement of Operations	2015			2014			2013
Interest and other income, net:
Available-for-sale securities:
Marketable securities	$	1,245		$	1,139		$	3,101
Auction rate securities		(512	)		—			—
Cash flow hedges:
Research and development		(198	)		3,329			(2,283	)
Selling and marketing		(8	)		266			(135	)
General and administrative		(12	)		24			(77	)
Total	$	515		$	4,758		$	606
Consolidated Statement of Operations
	Year Ended
	January 31,			February 1,			February 2,
	2015			2014			2013
Interest and other income, net:
Interest income	$	11,370			9,379			12,357
Realized gain on investments		1,449			1,299			3,238
Currency translation gain (loss)		1,871			8,739			(1,908	)
Other income		9,811			8,025			2,409
Interest expense		(1,167	)		(1,876	)		(563	)
	$	23,334		$	25,566		$	15,533
Net income per share
The Company reports both basic net income per share, which is based on the weighted average number of shares outstanding, and diluted net income per share, which is based on the weighted average number of shares outstanding and potentially dilutive shares. The computations of basic and diluted net income per share are presented in the following table (in thousands, except per share amounts):
	Year Ended
	January 31,			February 1,			February 2,
	2015			2014			2013
Numerator:
Net income	$	435,346		$	315,320		$	306,585
Denominator:
Weighted average shares — basic		511,089			496,518			555,310
Effect of dilutive securities:
Share-based awards		9,671			7,895			7,813
Weighted average shares — diluted		520,760			504,413			563,123
Net income per share:
Basic	$	0.85		$	0.64		$	0.55
Diluted	$	0.84		$	0.63		$	0.54
Anti-dilutive potential shares are presented in the following table (in thousands, except per share amounts):
	Year Ended
	January 31,			February 1,			February 2,
	2015			2014			2013
Weighted average shares outstanding from stock options:
Time-based options		22,485			36,882			25,133
Market-based options		2,288			2,711			2,991
		24,773			39,593			28,124
Weighted average exercise price:
Time-based options	$	17.58		$	15.12		$	17.72
Market-based options	$	15.43		$	15.43		$	15.43
Total	$	17.38		$	15.14		$	17.48
Anti-dilutive potential shares for stock options are excluded from the calculation of diluted earnings per share for the periods reported above because either their exercise price exceeded the average market price during the period or certain stock options with exercise prices less than the average market price were determined to be anti-dilutive based on applying the treasury stock method.

Derivative_Financial_Instrumen

Derivative Financial Instruments	12 Months Ended
	Jan. 31, 2015
Derivative Financial Instruments	Note 5 — Derivative Financial Instruments
	The Company manages some of its foreign currency exchange rate risk through the purchase of foreign currency exchange contracts that hedge against the short-term effect of currency fluctuations. The Company’s policy is to enter into foreign currency forward contracts with maturities less than 12 months that mitigate the effect of rate fluctuations on certain local currency denominated operating expenses. All derivative instruments are recorded at fair value in either prepaid expenses and other current assets or accrued liabilities. The Company reports cash flows from derivative instruments in cash flows from operating activities. The Company uses quoted prices to value its derivative instruments.
	The notional amounts of outstanding forward contracts were as follows (in thousands):
		Buy Contracts
		January 31,				February 1,
		2015				2014
	Israeli shekel	$	51,326			$	39,670
	Euro		—				5,718
	Swedish krona		—				3,709
		$	51,326			$	49,097
	Cash Flow Hedges. The Company designates and documents its foreign currency forward exchange contracts as cash flow hedges for certain operating expenses. The Company evaluates and calculates the effectiveness of each hedge at least quarterly. The effective change is recorded in accumulated other comprehensive income and is subsequently reclassified to operating expense when the hedged expense is recognized. Ineffectiveness is recorded in interest and other income, net.
	Other Foreign Currency Forward Contracts. The Company may enter into foreign currency forward exchange contracts to hedge certain assets and liabilities denominated in various foreign currencies that it does not designate as hedges for accounting purposes. The maturities of these contracts are generally less than 12 months. Gains or losses arising from the remeasurement of these contracts to fair value each period are recorded in interest and other income, net.
	The fair value of foreign currency exchange contracts was not significant as of any period presented.
	The following table provides information about gains (losses) associated with our derivative financial instruments (in thousands):
		Location of		Amount of Gains (Losses) in Statement
		Gains (Losses)		of Operations for the year ended
		Location of Gains (Losses)
		in Statement of Operations		January 31,				February 1,		February 2,
				2015				2014		2013
	Derivatives designated as cash flow hedges:
	Forward contracts:	Research and development		$	(1,930	)		$	3,099	$	(1,909	)
		Selling and marketing			(24	)			23		(13	)
		General and administrative			(157	)			246		(155	)
				$	(2,111	)		$	3,368	$	(2,077	)
	The portion of gains excluded from the assessment of hedge effectiveness are included in interest and other income, net, and these amounts were $0.2 million, $0.5 million and $0.4 million in fiscal 2015, 2014 and 2013, respectively. In addition, realized losses from forward contracts that are not designated as hedging instruments that are included in interest and other income, net, were not material in fiscal 2015, 2014 and 2013. The Company also reports hedge ineffectiveness from derivative financial instruments in current earnings, which were not material in fiscal 2015, 2014 and 2013. No cash flow hedges were terminated as a result of forecasted transactions that did not occur.

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Jan. 31, 2015
Fair Value Measurements	Note 6 — Fair Value Measurements
	Fair value is an exit price representing the amount that would be received in the sale of an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or a liability. As a basis for considering such assumptions, the accounting guidance establishes a three-tier value hierarchy, which prioritizes the inputs used in the valuation methodologies in measuring fair value:
	Level 1 — Observable inputs that reflect quoted prices for identical assets or liabilities in active markets.
	Level 2 — Include other inputs that are directly or indirectly observable in the marketplace.
	Level 3 — Unobservable inputs that are supported by little or no market activity.
	The fair value hierarchy also requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value.
	The Company’s Level 1 assets include institutional money-market funds that are classified as cash equivalents and marketable investments in U.S. government and agency debt, which are valued primarily using quoted market prices. The Company’s Level 2 assets and liabilities include its marketable investments in time deposits, corporate debt securities, foreign government and agency debt, municipal debt securities and asset back securities as the market inputs to value these instruments consist of market yields, reported trades and broker/dealer quotes, which are corroborated with observable market data. In addition, foreign currency forward contracts and the severance pay fund are classified within Level 2 as the valuation inputs are based on quoted prices and market observable data of similar instruments. The Company’s Level 3 assets include its investments in auction rate securities, which are classified within Level 3 because there are currently no active markets for the auction rate securities and consequently the Company is unable to obtain independent valuations from market sources. Therefore, the auction rate securities are valued using a discounted cash flow model. Some of the inputs to the cash flow model are unobservable in the market. The total amount of assets measured using Level 3 valuation methodologies represented 0.2% of total assets as of January 31, 2015.
	The tables below set forth, by level, the Company’s financial assets that were accounted for at fair value as of January 31, 2015 and February 1, 2014. The tables do not include assets and liabilities that are measured at historical cost or any basis other than fair value (in thousands):
		Fair Value Measurements at January 31, 2015
		Level 1			Level 2		Level 3		Total
	Items measured at fair value on a recurring basis:
	Assets
	Cash equivalents:
	Money market funds	$	111,286		$	—	$	—	$	111,286
	Time deposits		—			213,012		—		213,012
	Corporate debt securities		—			21,999		—		21,999
	Short-term investments:
	U.S. government and agency debt		179,156			—		—		179,156
	Corporate debt securities		—			986,317		—		986,317
	Asset backed securities		—			91,531		—		91,531
	Foreign government and agency debt		—			28,110		—		28,110
	Municipal debt securities		—			33,464		—		33,464
	Prepaid expenses and other current assets:
	Foreign currency forward contracts		—			124		—		124
	Long-term investments:
	Auction rate securities		—			—		10,226		10,226
	Other non-current assets:
	Severance pay fund		—			1,758		—		1,758
	Total assets	$	290,442		$	1,376,315	$	10,226	$	1,676,983
	Liabilities
	Accrued liabilities:
	Foreign currency forward contracts	$	—		$	1,379	$	—	$	1,379
		Fair Value Measurements at February 1, 2014
		Level 1			Level 2		Level 3		Total
	Items measured at fair value on a recurring basis:
	Assets
	Cash equivalents:
	Money market funds	$	2,804		$	—	$	—	$	2,804
	Time deposits		—			247,958		—		247,958
	Municipal debt securities		—			4,800		—		4,800
	U.S. government and agency debt		11,999					—		11,999
	Corporate debt securities		—			3,400		—		3,400
	Short-term investments:
	U.S. government and agency debt		301,479			—		—		301,479
	Corporate debt securities		—			589,514		—		589,514
	Asset backed securities		—			76,271		—		76,271
	Foreign government and agency debt		—			20,292		—		20,292
	Municipal debt securities		—			16,099		—		16,099
	Prepaid expenses and other current assets:
	Foreign currency forward contracts		—			1,012		—		1,012
	Long-term investments:
	Auction rate securities		—			—		16,279		16,279
	Other non-current assets:
	Severance pay fund		—			2,193		—		2,193
	Total assets	$	316,282		$	961,539	$	16,279	$	1,294,100
	Liabilities
	Accrued liabilities:
	Foreign currency forward contracts	$	—		$	26	$	—	$	26
	The following table summarizes the change in fair values for Level 3 assets for the year ended January 31, 2015 and February 1, 2014 (in thousands):
		Level 3
	Changes in fair value during the year (pre-tax):
	Ending balance at February 2, 2013	$	16,769
	Sales, redemption and settlement		(300	)
	Unrealized loss included in accumulated other comprehensive income		(190	)
Ending balance at February 1, 2014		16,279
Sales, redemption and settlement		(3,650	)
Transfer Out		(3,000	)
Unrealized loss included in accumulated other comprehensive income		597
Ending balance at January 31, 2015	$	10,226
The Company received notification by the issuer of a mandatory full call on November 6, 2014 of an auction rate security and as a result, the security was classified within Level 2 based on the issuer’s quoted price. By the end of fiscal 2015, the auction rate security was subsequently fully redeemed at par value.

Goodwill_and_Acquired_Intangib

Goodwill and Acquired Intangible Assets	12 Months Ended
	Jan. 31, 2015
Goodwill and Acquired Intangible Assets	Note 7 — Goodwill and Acquired Intangible Assets
	Goodwill
	The Company had no additions to goodwill in fiscal 2015 due to business combinations. In addition, the Company concluded there was no impairment of goodwill in fiscal 2015 based on its qualitative assessment that it was more likely than not the fair value of the reporting unit was greater than its carrying value.
	The following table summarizes the activity related to the carrying value of goodwill (in thousands):
	Balance at February 2, 2013	$	2,032,138
	Additions due to business combinations		400
	Sale of a business		(2,593	)
	Balance at February 1, 2014	$	2,029,945
	Balance at January 31, 2015	$	2,029,945
	Acquired Intangible Assets
	The carrying amounts of acquired intangible assets are as follows (in thousands):
					January 31, 2015							February 1, 2014
		Range of			Gross		Accumulated			Net		Gross		Accumulated			Net
		Useful Lives			Carrying		Amortization			Carrying		Carrying		Amortization			Carrying
					Amounts		and			Amounts		Amounts		and			Amounts
							Write-Offs							Write-Offs
	Purchased technology		4 - 7 years		$	35,498	$	(15,684	)	$	19,814	$	49,240	$	(20,634	)	$	28,606
	Core technology		5 - 8 years			850		(423	)		427		2,350		(1,583	)		767
	Trade names		5 years			1,300		(828	)		472		1,300		(568	)		732
	Customer intangibles		5 - 7 years			28,600		(18,615	)		9,985		28,600		(13,056	)		15,544
	IPR&D		*			—		—			—		3,386		—			3,386
	Total acquired intangible assets, net				$	66,248	$	(35,550	)	$	30,698	$	84,876	$	(35,841	)	$	49,035
	Intangible assets, along with the related accumulated amortization, are removed from the table above at the end of the fiscal year they become fully amortized. The Company recorded a charge to write-off $3.4 million of IPR&D in fiscal 2015, upon the Company’s decision to discontinue the related project. The Company also recorded charges of $8.1 million in fiscal 2014 for the impairment of an acquired intangible asset and $0.8 million in fiscal 2013 to write-off IPR&D related to an abandoned project. These impairment charges are included in amortization and write-off of acquired intangible assets in the consolidated statement of operations.
	Based on the identified intangible assets recorded at January 31, 2015, the future amortization expense of identified intangibles excluding IPR&D for the next five fiscal years is as follows (in thousands):
	Fiscal Year
	2016	$	12,212
	2017		11,027
	2018		5,599
	2019		1,860
	2020		—
		$	30,698

Restructuring

Restructuring	12 Months Ended
	Jan. 31, 2015
Restructuring	Note 8 — Restructuring
	Fiscal 2015.    In connection with ongoing evaluations of its business, the Company decided to streamline its operations, primarily in Israel to align with its overall strategic plan, and to discontinue the development of a product it originally acquired from a business that it previously purchased. These actions were substantially completed by the end of fiscal 2015. In addition, the Company decided to exercise an early buy out option to acquire an asset under an existing operating lease agreement, which will result in a loss from the termination of the agreement.
	Fiscal 2014.    The Company closed two sites for which it incurred severance and exit-related costs in connection with vacating the facilities, in addition to the write-off of equipment. All activities were substantially completed by the end of fiscal 2014.
	Fiscal 2013.    The Company incurred restructuring costs when the sublease of one of its previously vacated facilities was terminated in fiscal 2013.
	The following table presents detail of the related restructuring charges recorded by the Company (in thousands):
		Year Ended
		January 31,			February 1,			February 2,
		2015			2014			2013
	Severance and related costs	$	5,181		$	2,786		$	—
	Facilities and related costs		1,924			1,672			1,257
	Loss on early contract termination		3,230			—			—
	Other exit-related costs		86			213			—
			10,421			4,671			1,257
	Write-off of assets:
	Equipment		17			61			—
	Acquired intangible asset		3,386			—			—
		$	13,824		$	4,732		$	1,257
	Facilities and related costs include a charge for a portion of the lease obligation related to vacating the floors the Company no longer planned to occupy in one of its Israel facilities. The write-off of an acquired intangible asset in fiscal 2015 was due to the Company’s decision to discontinue the related project. Other exit-related costs are primarily associated with ongoing operating expenses related to vacated facilities under restructure actions in previous fiscal years.
	The following table presents details of restructuring charges by functional line item (in thousands):
		Year Ended
		January 31,			February 1,			February 2,
		2015			2014			2013
	Research and development	$	5,249		$	2,886		$	47
	Selling and marketing		—			795			(3	)
	General and administrative		5,189			1,051			1,213
	Write-off of acquired intangible assets		3,386			—			—
		$	13,824		$	4,732		$	1,257
	The following table sets forth a reconciliation of the beginning and ending restructuring liability balances by each major type of costs associated with the restructuring charges (in thousands):
		Severance			Facilities			Other			Total
		and Related			and Related			Exit-Related
		Costs			Costs			Costs
	Balance at February 2, 2013	$	—		$	2,855		$	—		$	2,855
	Restructuring charges		2,786			1,672			213			4,671
	Net cash payments		(2,735	)		(2,144	)		(194	)		(5,073	)
	Balance at February 1, 2014		51			2,383			19			2,453
	Restructuring charges		5,181			1,924			3,316			10,421
	Net cash payments		(5,232	)		(2,968	)		(105	)		(8,305	)
	Balance at January 31, 2015	$	—		$	1,339		$	3,230		$	4,569
	The balance at January 31, 2015 for facility and related costs includes remaining payments under lease obligations related to vacated space that are expected to be paid through fiscal 2018. Other exit-related costs include payment related to the exercise of the early buy out option for an asset under an existing operating lease agreement, which is expected to be paid in the first quarter of fiscal 2016.

Income_Taxes

Income Taxes	12 Months Ended
	Jan. 31, 2015
Income Taxes	Note 9 — Income Taxes
	The U.S. and non-U.S. components of income before income taxes consist of the following (in thousands):
		Year Ended
		January 31,			February 1,			February 2,
		2015			2014			2013
	U.S. operations	$	31,942		$	31,339		$	34,900
	Non-U.S. operations		400,211			274,918			275,290
		$	432,153		$	306,257		$	310,190
	The provision (benefit) for income taxes consists of the following (in thousands):
		Year Ended
		January 31,			February 1,			February 2,
		2015			2014			2013
	Current income tax provision (benefit):
	Federal	$	9,096		$	5,774		$	4,461
	State		(161	)		73			407
	Foreign		785			(18,829	)		(8,289	)
	Total current income tax provision (benefit)		9,720			(12,982	)		(3,421	)
	Deferred income tax provision (benefit):
	Federal		(1,775	)		317			6,306
	State		16			32			90
	Foreign		(11,154	)		3,570			630
	Total deferred income tax provision (benefit)		(12,913	)		3,919			7,026
	Total provision (benefit) for income taxes	$	(3,193	)	$	(9,063	)	$	3,605
	The income tax benefit for fiscal 2015 includes the current income tax liability of $17.4 million plus a $7.4 million increase in current unrecognized tax benefit. These charges were offset by a reduction in unrecognized tax benefits that arose from the release of $16.4 million due to the expiration of statute of limitations in non-U.S. jurisdictions and a $12.9 million increase in net deferred tax assets. The income tax benefit for fiscal 2014 included the current income tax liability of $13.2 million plus a $9.1 million increase in current unrecognized tax benefit which were offset by a reduction in unrecognized tax benefits that arose from the release of $31.8 million due to the expiration of statute of limitations and the settlement of an audit in non-U.S. jurisdictions. The provision for income taxes for fiscal 2013 consisted of the current income tax liability of $20.1 million plus a $8.0 million increase in current unrecognized tax benefit which were offset by a reduction in unrecognized tax benefits that arose from the release of $26.8 million due to the expiration of statute of limitations in non-U.S. jurisdictions.
	Deferred tax assets consist of the following (in thousands):
		January 31,			February 1,
		2015			2014
	Deferred tax assets:
	Federal and California research and other tax credits	$	382,726		$	335,894
	Reserves and accruals		35,538			25,833
	Share-based compensation		4,502			4,067
	Net operating losses		14,940			18,470
	Gross deferred tax assets		437,706			384,264
	Valuation allowance		(382,796	)		(335,890	)
	Total deferred tax assets		54,910			48,374
	Total deferred tax liabilities		(11,209	)		(17,586	)
	Net deferred tax assets	$	43,701		$	30,788
	As presented in the consolidated balance sheet as of January 31, 2015, deferred tax assets for certain net operating losses that are available to be used included in the table above have been offset by unrecognized tax benefits.
	The non-current portion of the deferred tax assets as of January 31, 2015 and February 1, 2014 was $22.3 million and $19.3 million, respectively, and is included in other non-current assets. During fiscal 2015, deferred tax assets, net of a corresponding valuation allowance increased $12.9 million from the end of fiscal 2014, mostly due to an increase in the Singapore deferred tax asset since the Company re-negotiated with the Singapore government and in fiscal 2015, they extended the Development and Expansion Incentive (“DEI”) until June 2019.
	As of January 31, 2015, the Company had net operating loss carryforwards available to offset future taxable income of approximately $58.2 million, $1.8 million and $7.4 million for foreign, U.S. federal and state of California purposes, respectively. The federal carryforwards will expire in various fiscal years between 2020 and 2024, and the California carryforwards will expire at various fiscal years between 2018 and 2033, if not utilized before these years. The losses in non-U.S. companies vary; some countries allows the loss be carried forward indefinitely while another allows only 15 years. For U.S. federal income tax return purposes, the Company had research tax credit carryforwards of approximately $233.2 million that expire through fiscal 2035. As of January 31, 2015, the Company had unused California research and tax credit carryforwards of approximately $239.1 million, which can be carryforward indefinitely. Included in the U.S. federal and California carryforward amounts are $56.8 million and $55.0 million, respectively, that are attributable to excess tax benefits from stock options. Upon realization, the benefit associated with these credits will increase additional paid-in capital. The Company also has research and investment tax credit carryforwards of approximately $20.8 million in other U.S. states that expire through fiscal 2030 due to the statute of limitation.
	At the end of fiscal 2015, the Company has provided a full valuation allowance against its federal and various state research credits which it earns in excess of its current year tax liabilities, as well as a portion against its net operating loss carryforwards. Based on the available objective positive and negative evidence, the Company has determined that it is more likely than not that these research credits and acquired net operating losses will not be realized. Therefore, the Company has recorded a valuation allowance of $382.8 million, an increase of $46.9 million from fiscal 2014.
	Reconciliation of the statutory federal income tax to the Company’s effective tax:
		Year Ended
		January 31,			February 1,			February 2,
		2015			2014			2013
	Provision at U.S. notional statutory rate		35	%		35	%		35	%
	Non-deductible share-based compensation		11.2			19.4			15.4
	Difference in U.S. and non-U.S. tax rates		(46.0	)		(55.8	)		(48.8	)
	Benefits from utilization of general business credits		(12.0	)		(14.1	)		(13.8	)
	Change in valuation allowance		10.5			11.9			12.9
	Other		0.6			0.6			0.5
	Effective tax rate		(0.7	)%		(3.0	)%		1.2	%
	The following table reflects changes in the unrecognized tax benefits (in thousands):
		Year Ended
		January 31,			February 1,			February 2,
		2015			2014			2013
	Unrecognized tax benefits as the beginning of the period	$	51,682		$	79,031		$	96,294
	Increases related to prior year tax positions		976			499			1,106
	Decreases related to prior year tax positions		(386	)		(111	)		—
	Increases related to current year tax positions		5,356			2,666			1,139
	Settlements		—			(7,423	)		(3,956	)
	Lapse in the statute of limitations		(10,691	)		(13,969	)		(15,543	)
	Foreign exchange gain		(1,740	)		(9,011	)		(9	)
	Gross amounts of unrecognized tax benefits as of the end of the period	$	45,197		$	51,682		$	79,031
Included in the balances as of January 31, 2015 is $38.5 million of unrecognized tax benefit that would affect the effective income tax rate if recognized. Also, a portion of the gross unrecognized tax benefits presented in the table above are offset in the consolidated balance sheet as of January 31, 2015 against deferred tax assets.
The amounts in the table above do not include the related interest and penalties. The amount of interest and penalties accrued as of January 31, 2015 was approximately $27.7 million, as of February 1, 2014 was approximately $29.6 million and as of February 2, 2013 was approximately $33.8 million. The consolidated statements of operations for fiscal 2015, 2014 and 2013 included $3.8 million, $6.2 million and $5.8 million, respectively, of interest and penalties related to the unrecognized tax benefits.
The Company is subject to income tax audits by the respective tax authorities in all of the jurisdictions in which it operates. The examination of tax liabilities in each of these jurisdictions requires the interpretation and application of complex and sometimes uncertain tax laws and regulations. As of January 31, 2015, the material jurisdictions that are subject to examination include China, Israel, Singapore, Switzerland and the United States for the Company’s fiscal years 2004 through 2014. As of January 31, 2015, several of the Company’s non-U.S. entities are under examination for fiscal years encompassing 2004 through 2013.
For fiscal 2015, the Company will continue to review its tax positions and provide for or reverse unrecognized tax benefits as issues arise. During the next 12 months, it is reasonably possible that the amount of unrecognized tax benefits could increase or decrease significantly due to changes in tax law in various jurisdictions, new tax audits and changes in the U.S. dollar as compared to foreign currencies within the next 12 months. Excluding these factors, uncertain tax positions may decrease by as much as $20 million from the lapse of the statutes of limitation in various jurisdictions during the next 12 months.
The Singapore Economic Development Board (“EDB”) initially granted a 10-year Pioneer Status in July 1999 to Company’s Singapore subsidiary. In October 2004, the Company’s subsidiary in Singapore was granted a second incentive known as the DEI, and in June 2006, the EDB agreed to extend the Pioneer status for 15 years to June 2014. The Company re-negotiated with the Singapore government and in fiscal 2015, they extended the DEI until June 2019. In fiscal 2015, 2014 and 2013 tax savings associated with these tax holidays were approximately $0.1 million, $3.7 million and $13.6 million, respectively, which if paid would impact the Company’s earnings per share less than $0.01 per share in fiscal 2015, $0.01 per share in fiscal 2014 and $0.02 per share in fiscal 2013.
Under the Israeli Encouragement law of “approved or benefited enterprise,” two branches of Marvell Israel (M.I.S.L) Ltd., the GTL branch and the cellular branch (formerly Marvell DSPC), are entitled to approved and benefited tax programs that include reduced tax rates and exemption of certain income. Income from the approved or benefited enterprises is eligible for fiscal years 2008 through fiscal 2027. For fiscal 2014 and 2013, the benefit associated with these approved or benefited enterprise programs was $2.2 million and $13.8 million, respectively, which provided earnings per share of $0.01 per share in fiscal 2014 and $0.02 per share in fiscal 2013. There was no such benefit in fiscal 2015.
During fiscal 2007, each of the Swiss Federal Department of Economy and the Vaud Cantonal Tax Administration granted the Company’s subsidiary in Switzerland a 10 year tax holiday on revenues from research and design wafer supply trading activities commencing with its fiscal 2007 and ending in fiscal 2016. The fiscal 2015, 2014 and 2013 tax savings associated with this tax holiday is approximately $4.5 million, $5.1 million and $4.6 million, respectively, which provided earnings per share of $0.01 per share in 2015, $0.01 per share in 2014 and less than $0.01 per share in fiscal 2013.
Our principal source of liquidity as of January 31, 2015 consisted of approximately $2.5 billion of cash, cash equivalents and short-term investments, of which approximately $900 million was held by foreign subsidiaries (outside Bermuda). Approximately $400 million of this amount held by foreign subsidiaries is related to undistributed earnings, which have been indefinitely reinvested outside of Bermuda. These funds are primarily held in China, Israel, Singapore, the United States and Switzerland. We have plans to use such amounts to fund various activities outside of Bermuda including working capital requirements, capital expenditures for expansion, funding of future acquisitions, or other financing activities. If such funds were needed by the parent company in Bermuda or if the amounts were otherwise no longer considered indefinitely reinvested, we would incur a tax expense of approximately $100 million.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Jan. 31, 2015
Commitments and Contingencies	Note 10 — Commitments and Contingencies
	Warranty Obligations
	The Company’s products carry a standard 90 day warranty with certain exceptions in which the warranty period can extend to more than one year based on contractual agreements. The Company’s warranty expense has not been significant in the periods presented.
	Lease Commitments
	The Company leases some of its facilities, equipment and computer aided design software under non-cancelable operating leases. Rent expense, net of sublease income for fiscal 2015, 2014, and 2013 was approximately $26.1 million, $25.8 million and $23.7 million, respectively. The Company also purchases certain intellectual property under technology license obligations. Future minimum lease payments, net of estimated sublease, and payments under technology license obligations as of January 31, 2015, are presented in the following tables (in thousands):
	Fiscal Year:	Minimum
		Operating
		Leases
		Payments
	2016	$	71,489
	2017		42,320
	2018		12,609
	2019		2,700
	2020		2,672
	Thereafter		3,722
	Total future minimum lease payments	$	135,512
	Fiscal Year:	Technology
		License
		Obligations
	2016	$	13,145
	2017		7,869
	2018		9,180
	2019		—
	2020		—
	Thereafter		—
	Total future minimum lease payments	$	30,194
	Less: amount representing interest		(1,236	)
	Present value of future minimum payments		28,958
	Less: current portion		(12,490	)
	Non-current portion	$	16,468
	Technology license obligations include the liabilities under the subscription agreements for technology licenses between the Company and various vendors.
	Purchase Commitments
	Under the Company’s manufacturing relationships with its foundry partners, cancellation of all outstanding purchase orders are allowed but require payment of all costs and expenses incurred through the date of cancellation. As of January 31, 2015, these foundries had incurred approximately $252.1 million of manufacturing costs and expenses relating to the Company’s outstanding purchase orders.
	Intellectual Property Indemnification
	The Company has agreed to indemnify certain customers for claims made against the Company’s products, where such claims allege infringement of third-party intellectual property rights, including, but not limited to, patents, registered trademarks, and/or copyrights. Under the aforementioned indemnification clauses, the Company may be obligated to defend the customer and pay for the damages awarded against the customer under an infringement claim as well as the customer’s attorneys’ fees and costs. The Company’s indemnification obligations generally do not expire after termination or expiration of the agreement containing the indemnification obligation. Generally, there are limits on and exceptions to the Company’s potential liability for indemnification. Although historically the Company has not made significant payments under these indemnification obligations, the Company cannot estimate the amount of potential future payments, if any, that it might be required to make as a result of these agreements. The maximum potential amount of any future payments that the Company could be required to make under these indemnification obligations could be significant.
	Contingencies
	The Company and certain of its subsidiaries are currently parties to various legal proceedings, including those noted in this section. The legal proceedings and claims described below could result in substantial costs and could divert the attention and resources of the Company’s management. The Company is also engaged in other legal proceedings and claims not described below, which arise in the ordinary course of its business. Litigation is subject to inherent uncertainties and unfavorable rulings could occur. An unfavorable ruling in litigation could require the Company to pay damages, one-time license fees or ongoing royalty payments, and could prevent the Company from manufacturing or selling some of its products or limit or restrict the type of work that employees involved in such litigation may perform for the Company, any of which could adversely affect financial results in future periods. The Company believes that its products do not infringe valid and enforceable claims and it will continue to conduct a vigorous defense in these proceedings. However, there can be no assurance that these matters will be resolved in a manner that is not adverse to the Company’s business, financial condition, results of operations or cash flows.
	As of January 31, 2015, the Company has a $3.2 million accrued liability related to certain legal proceedings described below in this section. The amount recorded does not relate to the litigation with Carnegie Mellon University (“CMU”). Other than for the matters that the Company has recognized in the consolidated financial statements, it has not recorded any amounts for contingent losses associated with the matters described below based on its belief that losses, while reasonably possible, are not probable. Unless otherwise stated, the Company is currently unable to predict the final outcome of these lawsuits and therefore cannot determine the likelihood of loss nor estimate a range of possible loss.
	Carnegie Mellon University Litigation.    On March 6, 2009, CMU filed a complaint in the U.S. District Court for the Western District of Pennsylvania naming Marvell Semiconductor, Inc. (“MSI”) and the Company as defendants and alleging patent infringement. CMU has asserted U.S. Patent Nos. 6,201,839 and 6,438,180 (collectively, the “CMU patents in suit”), which relate to read-channel integrated circuit devices and the hard disk drive (“HDD”) incorporating such devices. A jury trial began on November 26, 2012. On December 26, 2012, a jury delivered a verdict that found the CMU patents in suit were literally and willfully infringed and valid, and awarded past damages in the amount of $1.17 billion. CMU sought in its post-trial motions enhanced damages up to three times the jury verdict, pre-judgment interest up to $322 million, post-judgment interest, supplemental damages, attorneys’ fees, and an injunction and/or ongoing royalties. Post-trial motions were heard on May 1 and 2, 2013. On June 26, 2013, the District Court denied CMU’s post-trial motion for attorney fees without prejudice. On August 23, 2013, the District Court denied the Company’s motion for mistrial. On September 23, 2013, the District Court denied the Company’s motion for judgment as a matter of law or a new trial on non-infringement, invalidity and other non-damages issue as well as the Company’s motion for reduced damages. On the same day, the District Court granted-in-part CMU’s motion for a finding of willful infringement and enhanced damages, reserving its further rulings on any enhancement of the verdict for a separate opinion. On December 6, 2013, CMU filed a motion to permit registration of judgment and a motion for supplemental relief including a request to enjoin future share repurchases, any leveraged buyout or similar asset leveraging transaction, and dividends, in the absence of a court approved bond or other security. On December 23, 2013, the District Court denied the motions. On January 8, 2014, CMU filed a motion for telephonic status conference, which was denied on January 28, 2014. On January 14, 2014, the District Court denied the Company’s post-trial motion on laches. On March 31, 2014, the District Court rejected CMU’s motion for an injunction. The District Court also denied CMU’s request for pre-judgment interest, and substantially scaled back CMU’s request for enhanced damages. Based on these decisions, the District Court calculated the damages including enhancement to total approximately $1.54 billion, and held that, under its decision, CMU is entitled to post judgment interest and an ongoing royalty. On May 7, 2014, the District Court entered final judgment, from which the Company filed a notice of appeal on May 14, 2014. The Company filed its opening appeal brief on August 4, 2014. CMU filed its opposition brief on October 20, 2014 and the Company filed its reply brief on November 20, 2014. The District Court has required the Company to report ongoing royalties under the current judgment. Based on the royalty rate assessed by the District Court, such additional royalties for the period of time commencing on the date ordered by the District Court, January 15, 2013, through January 31, 2015 could be as much as $400 million. The Company has secured certain surety bonds for the duration of the appeal to stay execution of judgment pending the appeal. See “—Surety Bond.”
	The Company and MSI believe that the evidence and the law do not support the jury’s findings of infringement, validity and the award of damages and do not believe a material loss is probable. The Company believes that there are strong grounds for appeal and the Company and MSI are currently pursuing an appeal before the U.S. Court of Appeals for the Federal Circuit in Washington, D.C. which is set for oral argument in April 2015. The Company believes the low end of the possible range of loss is zero, but it cannot reasonably estimate the upper range of the possible loss, as a number of factors could significantly change the assessment of damages.
	USEI Litigation.    On October 9, 2009, U.S. Ethernet Innovations, LLC (“USEI”) filed a complaint in the U.S. District Court for the Eastern District of Texas, in which USEI has accused a number of system manufacturers, including the Company’s customers, of patent infringement (the “USEI litigation”). Specifically, USEI has asserted that these customers infringe U.S. Patent Nos. 5,307,459, 5,434,872, 5,732,094 and 5,299,313, which relate to Ethernet technologies. The complaint seeks unspecified damages and an injunction.
	On May 4, 2010, MSI filed a motion to intervene in the USEI litigation, which was granted on May 19, 2010. On July 13, 2010, the District Court issued an order granting the defendants’ motion to transfer the action to the U.S. District Court for the Northern District of California; the case was formally transferred on August 23, 2010. On September 14, 2011, USEI withdrew its allegations against MSI for the ‘459 patent. The District Court issued a first claim construction ruling on January 31, 2012 and a supplemental claim construction ruling on August 29, 2012. On August 16, 2013, the District Court granted defendants’ summary judgment motion to preclude the plaintiff from recovering certain pre-suit damages. On November 7, 2014, on summary judgment, the District Court found that all the patents-in-suit were either invalid or not infringed. On December 1, 2014, the District Court entered a judgment in favor of defendants and awarded defendants’ costs. On December 29, 2014, USEI filed a motion to alter or amend the District Court’s summary judgment order. The District Court has set a hearing date in March 2015.
	Lake Cherokee Patent Litigation.    On June 30, 2010, September 5, 2013 and September 25, 2013, Lake Cherokee Hard Drive Technologies, L.L.C. filed three separate complaints, which were consolidated into one case in the U.S. District Court for the Eastern District of Texas. All the parties involved in the three cases reached settlement in August 2014 and the three cases were dismissed with prejudice. The settlement did not have a significant impact on the Company’s financial statements.
	Azure Networks Litigation.    On March 22, 2011, Azure Networks, LLC (“Azure”) and Tri-County Excelsior Foundation filed suit in the U.S. District Court for the Eastern District of Texas against MSI and eight other companies. The Complaint asserts U.S. Patent No. 7,756,129 against MSI’s Bluetooth products. MSI filed its answer and counterclaims on July 20, 2011. On November 2, 2012, MSI and the other defendants filed a motion for summary judgment of invalidity, which was denied. A claim construction hearing was held on December 20, 2012. On January 15, 2013, the magistrate judge issued a claim construction ruling. On May 20, 2013, the District Court issued an order denying plaintiff’s motion for reconsideration and adopted the magistrate judge’s claim construction ruling. On May 30, 2013, the District Court entered a judgment of non-infringement. On June 24, 2013, Azure appealed, and the appeal has been briefed. Oral argument before a Federal Circuit panel was held on April 11, 2014. On November 6, 2014, the Federal Circuit issued an order vacating the judgment of non-infringement and remanding for further proceedings. On January 7, 2015, the District Court issued a supplemental claim construction order in light of the Federal Circuit remand and issued a scheduling order. The Company filed a petition for writ of certiorari to the United States Supreme Court on February 4, 2015. On February 10, 2015, the District Court stayed all proceedings pending the Supreme Court’s ruling on the Company’s petition.
	On January 13, 2015, Azure filed a second suit in the U.S. District Court for the Eastern District of Texas, alleging infringement of U.S. Patent Nos. 8,582,570; 8,582,571; 8,588,196; 8,588,231; 8,589,599; 8,675,590; 8,683,092; 8,700,815; 8,732,347; and 8,732,361, purportedly related to certain Wi-Fi and NFC technologies. The complaint seeks unspecified damages.
	Power Management Systems Litigation.    On August 22, 2011, Power Management Systems LLC (“PMS”), a subsidiary of Acacia Research Corp., filed a complaint against the Company’s subsidiary Marvell Semiconductor, Ltd. (“MSL”) and other defendants, in the U.S. District Court for the District of Delaware. On June 14, 2013, the District Court entered a judgment of non-infringement. The Federal Circuit Court of Appeals affirmed the District Court’s rulings on January 14, 2014. The deadline for PMS to appeal to the United States Supreme Court passed in mid-April 2014 without PMS taking any further action.
	France Telecom Litigation.    On June 26, 2012, France Telecom S.A. filed a complaint against MSI in the U.S. District Court for the Southern District of New York. The complaint asserts U.S. Patent No.5,446,747 against MSI’s communications processors and thin modems. The complaint seeks unspecified damages as well as injunctive relief. MSI answered the complaint on July 18, 2012 and August 1, 2012. On July 30, 2012, MSI filed a motion to transfer the lawsuit to the U.S. District Court for the Northern District of California. On September 17, 2012, the Court granted MSI’s motion and transferred the case to the Northern District of California. A claim construction hearing was held on December 13, 2013. On April 14, 2014, the Court denied MSI’s motion for summary judgment of invalidity, and granted MSI’s summary judgment motion concerning certain damages preclusion. A jury trial began on September 17, 2014. On September 30, 2014, a jury delivered a verdict that found the patent in suit was literally, but not willfully, infringed and valid, and awarded damages. The award did not have a significant impact on the Company’s financial statements. A hearing for post-trial motions and non-jury issues took place on January 14, 2015. On March 2, 2015, the District Court issued an order on post-trial briefs finding no direct infringement by Marvell as a matter of law and entered judgment in favor of Marvell.
	Freescale Litigation.    On July 6, 2012, Freescale Semiconductor, Inc. (“Freescale”) filed a complaint against MSI in the U.S. District Court for the Western District of Texas. On January 4, 2013, three of the Company’s subsidiaries, MSI, Marvell International Ltd. and Marvell World Trade Ltd., filed a complaint against Freescale in the U.S. District Court for the Western District of Texas. On April 11, 2014, the Court dismissed both of the above two cases with prejudice pursuant to a settlement and patent license agreement. The settlement did not have a significant impact on the Company’s financial statements.
	Progressive Semiconductor Solutions Patent Litigation.    On September 30, 2013, Progressive Semiconductor Solutions LLC (“PSS”) filed a complaint in the Central District of California against MSI and another defendant. On March 3, 2014, the District Court dismissed MSI without prejudice. On March 4, 2014, PSS filed a new complaint against MSI. The parties reached settlement in August 2014 and the case was dismissed with prejudice on August 21, 2014. The settlement did not have a significant impact on the Company’s financial statements.
	Vantage Point Technology Patent Litigation.    On November 21, 2013, Vantage Point Technology, Inc. (“VPT”) filed suit against a third-party defendant in the U.S. District Court for the Eastern District of Texas for patent infringement relating to processor technology. On February 3, 2014, VPT filed an amended complaint against the third party and added MSI as an additional defendant. The complaint seeks unspecified damages. On December 8, 2014, the case was transferred to the U.S. District Court for the Northern District of California. The case was dismissed with prejudice in March 2015.
	Voss Litigation and Consolidated Cases.    On April 7, 2014, Lee Voss (“Voss”) filed an action asserting putative class action claims on behalf of the Company’s shareholders and derivative claims ostensibly on behalf of the Company in the United States District Court for the Northern District of California, San Jose Division. This action was consolidated with two additional, nearly identical complaints from Sebastiano D’Arrigo and James and Marie DiBiase. The complaint alleged that certain officers and directors of the Company breached their fiduciary duties by causing or allowing the Company to engage in the purported willful infringement of certain patents asserted against it in litigation by CMU and by failing to institute adequate internal controls, resulting in an adverse verdict, and alleged unjust enrichment and a breach of the duty of honest services by three of the Company’s officers. The Company was named as a nominal defendant. The complaint requested damages and restitution in unspecified amounts, equitable and/or injunctive relief, and the costs and fees of bringing the action. The Company and the defendant officers and directors filed a motion to dismiss the amended consolidated complaint on September 4, 2014. On January 26, 2015, the District Court granted the Company’s motion to dismiss with leave to amend and on February 24, 2015, the District Court granted the plaintiffs’ motion to dismiss without prejudice.
	Bandspeed Litigation.    On May 9, 2014, Bandspeed, Inc. filed suit against MSI in the U.S. District Court for the Eastern District of Texas, alleging infringement of U.S. Patent Nos. 7,027,418; 7,570,614; 7,477,624; 7,903,608; and 8,542,643, purportedly related to certain Bluetooth technology. The complaint seeks unspecified damages. On February 13, 2015, Bandspeed amended its complaint and added allegations of infringement of U.S. Patent No. 8,873,500. A claim construction hearing is currently scheduled for October 2, 2015.
	SOTA Litigation.    On October 24, 2014, SOTA Semiconductor LLC (“SOTA”) filed suit against MSI, alleging infringement of U.S. Patent Nos. 5,991,545 and 6,643,713, purportedly related to certain processor technology. The complaint sought unspecified damages. The parties reached settlement and the case was dismissed with prejudice on January 20, 2015. The settlement did not have a significant impact on the Company’s financial statements.
	NXP Litigation.    On January 22, 2015, NXP Semiconductors N.V. filed suit against MSI in the U.S. District Court for the Northern District of California, alleging infringement of U.S. Patent Nos. 5,939,791; 7,039,133; 8,185,050; and 8,203,432, purportedly related to certain NFC technology. The complaint seeks unspecified damages. MSI filed its response and counterclaims on February 26, 2015. Marvell International Limited (“MIL”) also filed counterclaims against NXP Semiconductors U.S.A. (“NXP USA”), alleging infringement of U.S. Patent Nos. 7,047,393; 7,555,065; and 7,302,600. On February 2, 2015, MIL filed suit against NXP USA in the U.S. District Court for the Central District of California, alleging patent infringement of U.S. Patent Nos. 8,171,309; 7,957,777; 7,454,634; and 6,903,448, related to certain NFC and automotive technologies.
	Paone Litigation.    On February 6, 2015, Luciano F. Paone filed suit against MSI in the U.S. District Court for the Eastern District of New York, alleging infringement of U.S. Patent No. 6,259,789, purportedly related to certain encryption technology. The complaint seeks unspecified damages.
	Innovatio Litigation.    On March 16, 2015, Innovatio IP Ventures, LLC filed suit against MSI in the U.S. District Court for the Northern District of Illinois, alleging infringement of U.S. Patent Nos. 6,697,415; 5,844,893; 5,740,366; 7,916,747; 6,665,536; 7,013,138; 7,107,052; 5,546,397; 7,710,907; 7,710,935; 6,714,559; 7,457,646; and 6,374,311, purportedly related to certain wireless technology. The complaint seeks unspecified damages.
	Surety Bond
	On May 14, 2014, the Company filed a Notice of Appeal to appeal the final judgment issued by the District Court in the CMU litigation. In order to stay the execution of the final judgment pending its appeal, the Company filed a supersedeas bond for $1.54 billion with the District Court. The bond was issued by a consortium of sureties authorized by the U.S. Treasury. If the judgment is affirmed after the completion of all appellate proceedings, and the Company does not thereafter fully satisfy the judgment within thirty days, the sureties are obligated under the bond to make payment to CMU. In support of the bond, the Company entered into separate indemnity agreements with each of the sureties to indemnify the sureties from all costs and payments made under the bond. The indemnity agreements did not require collateral to be posted at the time of the issuance of the bond. Therefore no cash is considered restricted as of the date of this filing. However, the indemnity agreements provide that each of the sureties have the right to demand to be placed in funds or call for collateral under pre-defined events. The indemnity agreements will remain outstanding for as long as the underlying bond remains outstanding.
	The Court has required us to report ongoing royalties under the current judgment. Based on the royalty rate assessed by the District Court, such additional royalties for the period of time commencing on the date ordered by the District Court, January 15, 2013, through January 31, 2015 could be as much as $400 million. On November 14, 2014, the Company filed a second surety bond for $216 million and filed a commitment letter from the sureties to issue up to an additional $95 million in bonding under certain conditions. The second bond and commitment are secured by the Company’s campus located in Santa Clara, California, which has a carrying value of $139 million at January 31, 2015. The Company and CMU have agreed that the second bond and commitment satisfy the security for ongoing royalties while the appeal is pending.
	Indemnities, Commitments and Guarantees
	During its normal course of business, the Company has made certain indemnities, commitments and guarantees under which it may be required to make payments in relation to certain transactions. These indemnities may include intellectual property indemnities to the Company’s customers in connection with the sales of its products, indemnities for liabilities associated with the infringement of other parties’ technology based upon the Company’s products, indemnities for general commercial obligations, indemnities to various lessors in connection with facility leases for certain claims arising from such facility or lease, and indemnities to directors and officers of the Company to the maximum extent permitted under the laws of Bermuda. In addition, the Company has contractual commitments to various customers, which could require the Company to incur costs to repair an epidemic defect with respect to its products outside of the normal warranty period if such defect were to occur. The duration of these indemnities, commitments and guarantees varies, and in certain cases, is indefinite. Some of these indemnities, commitments and guarantees do not provide for any limitation of the maximum potential future payments that the Company could be obligated to make. In general, the Company does not record any liability for these indemnities, commitments and guarantees in the accompanying consolidated balance sheets as the amounts cannot be reasonably estimated and are not considered probable. The Company does, however, accrue for losses for any known contingent liability, including those that may arise from indemnification provisions, when future payment is probable.

Benefit_Plans

Benefit Plans	12 Months Ended
	Jan. 31, 2015
Benefit Plans	Note 11 — Benefit Plans
	The Company sponsors a 401(k) savings and investment plan that allows eligible U.S. employees to participate by making pre-tax contributions to the 401(k) plan ranging from 1% to 50% of eligible earnings subject to a required annual limit. The Company matches 100% of the employee contribution up to $500 per eligible employee on a quarterly basis. The participant must be employed by the Company on the last day of the calendar quarter to qualify for the match. At the end of the calendar year, the eligible employees receive a true-up match equal to the accumulated employee contribution for the calendar year up to $2,000. The Company made matching contributions to employees of $5.1 million during each of fiscal 2015, 2014 and 2013. As of January 31, 2015, the 401(k) plan offers a variety of investment alternatives, representing different asset classes. Employees may not invest in the Company’s common shares through the 401(k) plan.
	The Company also has voluntary defined contribution plans in various non-U.S. locations. The Company made contributions on behalf of employees totaling $18.6 million, $20.6 million and $17.2 million during fiscal 2015, 2014 and 2013, respectively. The Company also maintains a limited number of defined benefit plans for certain non-U.S. locations. Total costs under these plans were not significant.

Shareholders_Equity

Shareholders' Equity	12 Months Ended
	Jan. 31, 2015
Shareholders' Equity	Note 12 — Shareholders’ Equity
	Common and Preferred Stock
	As of January 31, 2015, the Company is authorized to issue 992.0 million shares of $0.002 par value common stock and 8.0 million shares of $0.002 par value preferred stock. As of January 31, 2015 and February 1, 2014, no shares of preferred stock were outstanding.
	1995 Stock Option Plan
	In April 1995, the Company adopted the 1995 Stock Option Plan (the “Option Plan”). The Option Plan, as amended from time to time, had 383.4 million common shares reserved for issuance thereunder as of January 31, 2015. Options granted under the Option Plan generally have a term of 10 years and generally must be issued at prices equal to the fair market value of the stock on the date of grant. Incentive stock options granted to shareholders who own greater than 10% of the outstanding stock at the time of the grant may not have a term exceeding five years and these options must be issued at prices of at least 110% of the fair market value of the stock on the date of grant.
	The Company can also grant stock awards, which may be subject to vesting. Further, the Company can grant restricted stock unit awards. Restricted stock unit awards are denominated in shares of stock, but may be settled in cash or shares upon vesting, as determined by the Company at the time of grant.
	Equity awards to new hires under the Option Plan generally vest 20% one year after the vesting commencement date and the remaining shares vest one-sixtieth per month over the remaining 48 months. Other equity awards generally vest annually in four equal installments.
	In fiscal 2015, the Company granted performance-based restricted stock units (“PSUs”) to certain members of senior management. Pursuant to the PSUs, each eligible employee is entitled to vest in a certain number of shares based on such employee’s achievement of individual financial and strategic performance goals for fiscal 2015, including, for example, net revenue and operating expense targets, and other individual strategic milestones. The actual number of shares that vest for each eligible employee is based on the achievement of such performance goals determined at the end of fiscal 2015 and vest over two years, with 50% vesting on April 1, 2015 and 50% vesting on April 1, 2016. The Company recognizes expenses associated with the PSUs when it becomes probable that the performance conditions will be met. Once it becomes probable that a PSU will vest, the Company recognizes compensation expense equal to the number of shares multiplied by the fair value of the related shares measured at the grant date.
	In fiscal 2015, the Company also granted performance-based equity awards to each of our executive officers which are based on their achievement of certain performance goals in fiscal 2015 and 2016. These equity awards include restricted stock units which vest based on financial performance criteria (“Financial Performance RSU”) and restricted stock units which vest based on both financial performance criteria and individual strategic goals (“Strategic Performance Award”). The Financial Performance RSUs will be earned based on the achievement of revenue and modified non-GAAP operating income that have been established at “threshold,” “target” and “maximum” levels. Each Financial Performance RSU will vest 50% on the first anniversary of the commencement date based on achievement of fiscal 2015 financial performance criteria and 50% on the second anniversary of the vesting commencement date based on the achievement of fiscal 2016 financial performance criteria. The Strategic Performance Awards will vest based on achievement at the threshold level of either the revenue or modified non-GAAP operating income objective established for the Financial Performance RSU, in addition to the achievement of additional individual strategic goals. Each Strategic Performance Award will vest 50% on the first anniversary of the commencement date based on achievement of fiscal 2015 individual strategic goals and 50% on second anniversary date based on the achievement of the fiscal 2016 individual strategic goals.
	In March 2015, the Executive Compensation Committee of the Company’s Board of Directors completed its evaluation of the number of shares to be issued to the Company’s executive officers based on their achievement of the fiscal 2015 performance goals and determined that 478,001 shares would vest on April 1, 2015. As a result, there was no material adjustment to the related share-based compensation expense in fiscal 2015.
	As of January 31, 2015, approximately 90.0 million shares remained available for future issuance under the Option Plan.
	1997 Directors’ Stock Option Plan
	In August 1997, the Company adopted the 1997 Directors’ Stock Option Plan (the “1997 Directors’ Plan”). Under the 1997 Directors’ Plan, an outside director was granted an option to purchase 30,000 common shares upon appointment to the Company’s Board of Directors. These options vested 20% one year after the vesting commencement date and remaining shares vest one-sixtieth per month over the remaining 48 months. An outside director was also granted an option to purchase 6,000 common shares on the date of each annual meeting of the shareholders. These options vested one-twelfth per month over 12 months after the fourth anniversary of the vesting commencement date. Options granted under the 1997 Directors’ Plan could be exercised prior to vesting and had a term of 10 years. The 1997 Directors’ Plan was terminated in October 2007. There are two outstanding grants remaining under the 1997 Directors’ Plan.
	2007 Directors’ Stock Incentive Plan
	In October 2007, the Company adopted the 2007 Directors’ Stock Incentive Plan, for which shareholders approved a total of 750,000 common shares that could be issued under the plan to all eligible outside directors. Each outside director was granted an option to purchase 50,000 common shares upon his or her initial appointment to the Company’s Board of Directors. These options, which have a term of 10 years, vested one-third of the total shares on the one-year anniversary of the date of grant and one-third of the total shares on each one-year anniversary thereafter. From time to time, the Board has the authority to approve the amendment and restatement of the plan to revise the size of automatic annual awards granted under the plan.
	In fiscal 2012, each outside director who had been serving on the Company’s Board of Directors for the prior six months and was re-elected by the shareholders at the annual general meeting was granted an option to purchase 9,000 common shares. These options, which have a term of 10 years, vested 100% on the earlier of the date of the next annual general meeting of shareholders or the one-year anniversary of the date of grant. In addition, each outside director was also granted a restricted stock unit (“RSU”) award for a number of shares with an aggregate fair market value equal to $70,000 immediately following the annual general meeting of shareholders. These RSU awards vested 100% on the earlier of the date of the next annual general meeting of shareholders or the one-year anniversary of the date of grant.
	In fiscal 2013 and 2014, each outside director who was appointed at the annual general meeting of shareholders was granted an option to purchase a number of common shares with an aggregate grant date fair value equal to $110,000 immediately following the annual general meeting of shareholders. In addition, each outside director who was elected or appointed at the annual general meeting of shareholders was granted an RSU award for a number of shares with an aggregate fair market value equal to $110,000 immediately following each annual general meeting. The option awards, which have a term of 10 years, and the RSU awards vest 100% on the earlier of the date of the next annual general meeting of shareholders or the one-year anniversary of the date of grant. An outside director elected or appointed after an annual general meeting of shareholders would receive a pro rata stock option award and RSU award based on the number of quarters completed since the previous annual general meeting of shareholders. In no event would any outside director be awarded in any calendar year an annual option award or annual RSU award under the 2007 Director Plan for more than 25,000 shares and 10,000 shares, respectively.
	Beginning in fiscal 2015, each outside director who is first elected or appointed at the annual general meeting of shareholders will be granted an RSU award for a number of shares with an aggregate fair market value equal to $220,000 immediately following each annual general meeting of shareholders. The RSU award vests as to 100% of the shares on the earlier of the date of the next annual general meeting of shareholders or the one-year anniversary of the date of grant. An outside director who is elected or appointed after an annual general meeting of shareholders will receive a pro rata RSU award based on the number of quarters completed since the prior annual general meeting of shareholders. In no event shall any outside director be awarded in any calendar year an annual RSU award under the 2007 Director Plan for more than 20,000 shares, respectively.
	As of January 31, 2015, approximately 144,692 shares remained available for future issuance under the 2007 Directors’ Plan.
	2000 Employee Stock Purchase Plan
	Under the 2000 Employee Stock Purchase Plan, as amended and restated on October 31, 2011 (the “ESPP”), participants purchase the Company’s stock using payroll deductions, which may not exceed 15% of their total cash compensation. Pursuant to the terms of the current ESPP, the “look-back” period for the stock purchase price is 24 months. Offering and purchase periods begin on December 8 and June 8 of each year. Participants enrolled in a 24-month offering period will continue in that offering period until the earlier of the end of the offering period or the reset of the offering period. A reset occurs if the fair market value of the Company’s common shares on any purchase date is less than it was on the first day of the offering period. Participants in a 24-month offering period will be granted the right to purchase common shares at a price per share that is 85% of the lesser of the fair market value of the shares at (i) the participant’s entry date into the two-year offering period or (ii) the end of each six-month purchase period within the offering period.
	During fiscal 2015, a total of 9.7 million shares were issued under the ESPP at a weighted-average price of $7.67. During fiscal 2014, a total of 9.7 million shares were issued under the ESPP at a weighted-average price of $7.39. During fiscal 2013, a total of 7.6 million shares were issued under the ESPP at a weighted-average price of $8.77. As of January 31, 2015, there was $39.7 million of unrecognized compensation cost related to the ESPP.
	As of January 31, 2015, approximately 14.8 million shares remained available for future issuance under the ESPP.
	Option Plan and Stock Award Activity
	Stock option activity under the Company’s stock option and stock incentive plans is included in the following table (in thousands, except for per share amounts):
			Time-Based Options						Market-Based Options						Total
			Options			Weighted			Options			Weighted			Options			Weighted
			Outstanding			Average			Outstanding			Average			Outstanding			Average
						Exercise						Exercise						Exercise
						Price						Price						Price
	Balance at January 28, 2012			52,467		$	12.53			3,124		$	15.43			55,591		$	12.7
	Granted			7,041		$	14.59			—			—			7,041		$	14.59
	Exercised			(5,977	)	$	6.44			—			—			(5,977	)	$	6.44
	Canceled/Forfeited			(3,894	)	$	16.1			(365	)	$	15.43			(4,259	)	$	16.04
	Balance at February 2, 2013			49,637		$	13.28			2,759		$	15.43			52,396		$	13.39
	Granted			18,922		$	10.82			—			—			18,922		$	10.82
	Exercised			(15,482	)	$	9.4			—			—			(15,482	)	$	9.4
	Canceled/Forfeited			(3,921	)	$	15.15			(136	)	$	15.43			(4,057	)	$	15.16
	Balance at February 1, 2014			49,156		$	13.4			2,623		$	15.43			51,779		$	13.51
	Granted			6,365		$	15.33			—			—			6,365		$	15.33
	Exercised			(3,732	)	$	10.19			—			—			(3,732	)	$	10.19
	Canceled/Forfeited			(4,649	)	$	14.66			(391	)	$	15.43			(5,040	)	$	14.72
	Balance at January 31, 2015			47,140		$	13.79			2,232		$	15.43			49,372		$	13.88
	Vested or expected to vest at January 31, 2015			44,470		$	13.84
	Exercisable at January 31, 2015			22,457		$	15.31
	For time-based stock options vested and expected to vest at January 31, 2015, the aggregate intrinsic value was $122.1 million and the weighted average remaining contractual term was 5.9 years. For time-based stock options exercisable at January 31, 2015, the aggregate intrinsic value was $51.9 million and the weighted average remaining contractual term was 3.5 years. The aggregate intrinsic value of stock options exercised during fiscal 2015, 2014 and 2013 was $19.3 million, $51.1 million and $33.6 million, respectively. There was no aggregate intrinsic value for market-based stock options at January 31, 2015 and the weighted average remaining contractual term of market-based stock options vested and expected to reach the end of the vesting period at January 31, 2015 was 6.2 years. The Company’s closing stock price of $15.49 as reported on the NASDAQ Global Select Market as of January 30, 2015 was used to calculate the aggregate intrinsic value for all in-the-money options.
	As of January 31, 2015, the unamortized compensation expense for time-based stock options was $53.3 million and market-based stock options were fully amortized in fiscal 2014. The unamortized compensation expense for time-based options will be amortized on a straight-line basis and is expected to be recognized over a weighted-average period of 2.3 years.
	Activity related to the non-vested portion of the restricted stock units is included in the following table (in thousands, except for share prices):
			Time-Based						Performance-Based						Total
			Number of			Weighted			Number of			Weighted			Number of			Weighted
			Shares			Average			Shares			Average			Shares			Average
						Grant  Date						Grant Date						Grant Date
						Fair Value						Fair Value						Fair Value
	Balance at January 28, 2012			9,646		$	17.38
	Granted			7,370		$	14.64
	Vested			(2,796	)	$	17.78
	Canceled/Forfeited			(1,481	)	$	17.16
	Balance at February 2, 2013			12,739		$	15.78
	Granted			3,728		$	10.79			100		$	10.52			3,828		$	10.78
	Vested			(3,925	)	$	16.19			—		$	—			—		$	—
	Canceled/Forfeited			(1,288	)	$	14.39			—		$	—			—		$	—
	Balance at February 1, 2014			11,254		$	14.14			100		$	10.52			11,354		$	14.11
	Granted			5,534		$	15.2			1,277	*	$	14.98	*		6,811		$	15.16
	Vested			(5,938	)	$	13.96			(3	)	$	10.52			(5,941	)	$	13.96
Canceled/Forfeited			(1,102	)	$	14.32			(120	)	$	11.23			(1,222	)	$	14.02
Balance at January 31, 2015			9,748		$	14.84			1,254		$	14.99			11,002		$	14.85
*	Amounts represent the target number of restricted stock units at grant date. For awards granted to our executive officers, up to 200% of the target restricted stock units may vest if the maximum level for financial and strategic goals is achieved.
The aggregate intrinsic value of restricted stock units expected to vest as of January 31, 2015 was $160.3 million. The number of restricted stock units that are expected to vest is 10.4 million shares.
As of January 31, 2015, unamortized compensation expense related to restricted stock units was $87.5 million. The unamortized compensation expense for restricted stock units will be amortized on a straight-line basis and is expected to be recognized over a weighted-average period of 1.3 years.
Share-Based Compensation
The following table presents details of share-based compensation expenses by functional line item (in thousands):
		Year Ended
		January 31,			February 1,			February 2,
		2015			2014			2013
Cost of goods sold		$	7,972		$	8,863		$	8,142
Research and development			94,432			109,432			87,149
Selling and marketing			11,469			13,940			13,278
General and administrative			23,373			23,638			18,711
		$	137,246		$	155,873		$	127,280
Share-based compensation capitalized in inventory was $1.5 million at January 31, 2015, $1.7 million at February 1, 2014, and $1.5 million at February 2, 2013.
Valuation Assumptions
The expected volatility for awards granted during fiscal 2015, 2014, and 2013 was based on an equally weighted combination of historical stock price volatility and implied volatility derived from traded options on the Company’s stock in the marketplace. The Company believes that the combination of historical volatility and implied volatility provides a better estimate of future stock price volatility.
The expected dividend yield is calculated by dividing the current annualized dividend by the closing stock price on the date of grant of the option.
The following weighted average assumptions were used for each respective period to calculate the fair value of each time-based equity award on the date of grant using the Black-Scholes option pricing model and of each market-based equity award using a Monte Carlo simulation model:
		Year Ended
		January 31,			February 1,			February 2,
		2015			2014			2013
Time-based Stock Options:
Weighted average fair value		$	4.35		$	3.43		$	5.52
Expected volatility			35	%		45	%		44	%
Expected term (in years)			5			5			4.8
Risk-free interest rate			1.6	%		0.8	%		0.9	%
Expected dividend yield			1.6	%		2.4	%		0.3
There were no market-based stock options granted during fiscal 2015, 2014 and 2013. In fiscal 2012, the Company issued 3.1 million stock options with a market-based condition for a group of senior employees. If the market price condition is not met within five years from the date of grant, the options automatically expire. The fair value of each market-based stock option award was estimated on the date of grant using a Monte Carlo simulation model that uses the assumptions noted in the above table, including the same volatility applied to the Company’s time-based options. Because a Monte Carlo simulation model incorporates ranges of assumptions for inputs, those ranges are disclosed where applicable. The Company uses historical data to estimate employee termination within the valuation model. The expected term was 2.66 years for market-based stock options granted in fiscal 2012 and was derived from the output of the valuation model and represents the period of time that options granted are expected to be outstanding.
		Year Ended
		January 31,			February 1,			February 2,
		2015			2014			2013
Employee Stock Purchase Plan:
Estimated fair value		$	4.1		$	3.65		$	3.13
Expected volatility			30	%		37	%		40	%
Expected term (in years)			1.3			1.3			1.2
Risk-free interest rate			0.3	%		0.2	%		0.2	%
Expected dividend yield			1.6	%		2	%		2.4
Share Repurchase Program
The Company’s board of directors initially authorized its current share repurchase program to repurchase up to $500 million of its outstanding common shares in August 2010. Since then, the Company’s board of directors have authorized an additional $2.8 billion for a total available under the program of $3.3 billion to be used to repurchase its common shares. The Company intends to effect share repurchases in accordance with the conditions of Rule 10b-18 under the Exchange Act but may also make repurchases in the open market outside of Rule 10b-18 or in privately negotiated transactions. The share repurchase program will be subject to market conditions and other factors, and does not obligate the Company to repurchase any dollar amount or number of its common shares and the repurchase program may be extended, modified, suspended or discontinued at any time.
The Company repurchased 5.1 million of its common shares for $65.0 million in cash during fiscal 2015, 33.1 million of its common shares for $354.1 million in cash during fiscal 2014 and 91.0 million of its common shares for $959.1 million in cash during fiscal 2013. All of the repurchased shares were retired immediately after the repurchases were completed. The Company records all repurchases, as well as investment purchases and sales, based on trade date. As of January 31, 2015, a total of 222.0 million cumulative shares have been repurchased under the Company’s share repurchase program for a total $2.8 billion in cash and there was $443.5 million remaining available for future share repurchases.
Dividends
		Year Ended
		January 31,			February 1,			February 2,
		2015			2014			2013
Cash dividend per share		$	0.24		$	0.24		$	0.18
Total payment to shareholders (in thousands)		$	122,801		$	119,449		$	98,761
Future payment of a regular quarterly cash dividend on the Company’s common shares will be subject to, among other things, the best interests of the Company, the Company’s results of operations, cash balances and future cash requirements, financial condition, statutory requirements under Bermuda law and other factors that the Company’s board of directors may deem relevant. The Company’s dividend payments may change from time to time, and the Company cannot provide assurance that it will continue to declare dividends at all or in any particular amounts. In addition, developments in ongoing litigation could affect the Company’s ability to make a dividend payment on a declared payment date until such time as the Company can meet statutory requirements under Bermuda law.
On February 19, 2015, the Company announced that its board of directors declared a cash dividend of $0.06 per share to be paid on April 2, 2015 to shareholders of record as of March 12, 2015.

Segment_and_Geographic_Informa

Segment and Geographic Information	12 Months Ended
	Jan. 31, 2015
Segment and Geographic Information	Note 13 — Segment and Geographic Information
	The Company operates in one reportable segment — the design, development and sale of integrated circuits. The chief executive officer has been identified as the chief operating decision maker (“CODM”). The Company’s CODM is ultimately responsible and actively involved in the allocation of resources and the assessment of the Company’s operational and financial performance. The fact that the Company operates in only one reportable segment is based on the following:
		•		The Company uses a highly integrated approach in developing its products in that discrete technologies developed by the Company are frequently integrated across many of its products. Substantially all of the Company’s integrated circuits are manufactured under similar manufacturing processes.
		•		The Company’s organizational structure is based along functional lines. Each of the functional department heads reports directly to the CODM. Shared resources in the Company also report directly to the CODM or to a direct report of the CODM.
		•		The assessments of performance across the Company, including assessment of the Company’s incentive compensation plan, are based largely on operational performance and consolidated financial performance.
		•		The decisions on allocation of resources and other operational decisions are made by the CODM based on his hands-on involvement with the Company’s operations and product development.
	The following tables present net revenue and long-lived asset information based on geographic region. Net revenue is based on the destination of the shipments and long-lived assets are based on the physical location of the assets (in thousands):
			Year Ended
	Net Revenue:		January 31,		February 1,		February 2,
			2015		2014		2013
	United States		$	62,333	$	68,321	$	176,581
	China			2,214,876		1,869,381		1,599,681
	Thailand			294,706		353,363		369,855
	Malaysia			377,903		352,756		351,401
	Philippines			254,381		257,899		246,269
	Others			502,764		502,680		424,843
			$	3,706,963	$	3,404,400	$	3,168,630
	Property and equipment, net:		January 31,		February 1,
			2015		2014
	Bermuda		$	3,358	$	4,453
	China			25,910		29,146
	Israel			26,728		33,758
	Singapore			79,216		76,367
	United States			186,321		195,253
	Others			19,106		17,188
			$	340,639	$	356,165
	The following table presents net revenue by end market (in thousands):
			Year Ended
	Net Revenue by End Market		January 31,		February 1,		February 2,
			2015		2014		2013
	Storage		$	1,744,656	$	1,681,953	$	1,494,959
	Mobile and Wireless			1,071,777		839,407		822,533
	Networking			674,701		670,249		708,821
	Other			215,829		212,791		142,317
			$	3,706,963	$	3,404,400	$	3,168,630

Related_Party_Transactions

Related Party Transactions	12 Months Ended
	Jan. 31, 2015
Related Party Transactions	Note 14 — Related Party Transactions
	MIL is party to a technology license agreement with VeriSilicon Holdings Co., Ltd. (“VeriSilicon”). MIL assumed the technology license agreement between VeriSilicon and UTStarcom, Inc. after the Company’s acquisition of the semiconductor business of UTStarcom in December 2005. MIL has subsequently entered into various addenda to the agreement for additional technology beyond the scope of the original agreement. In addition, in September 2010, MIL entered into a services agreement with VeriSilicon, pursuant to which VeriSilicon has agreed to provide design support services to MIL. Under the services agreement, VeriSilicon helped on three projects for MIL during fiscal 2013. In connection with all of its transactions with VeriSilicon, MIL paid $3.7 million, $2.0 million and $2.8 million to VeriSilicon during fiscal 2015, 2014 and 2013, respectively. As of January 31, 2015, the Company had $0.8 million of liability to VeriSilicon. Weili Dai’s brother (and Dr. Sehat Sutardja’s brother-in-law) is the Chairman, President and Chief Executive Officer of VeriSilicon. Ms. Dai is also a shareholder of VeriSilicon. Ms. Dai is President of the Company and Dr. Sehat Sutardja is the Company’s Chief Executive Officer. Dr. Sehat Sutardja and Ms. Dai are husband and wife.
	In December 2009, MIL entered into a technology license agreement with Vivante Corporation (“Vivante”) that provides for the license of graphics technology and associated services. This agreement restates, expands and succeeds previous agreements between the parties for the same technology. In December 2012, the parties renewed this technology license agreement for another three years. The total amount of the license fee was approximately $13.0 million (to be paid over three years) and ten percent for support fees (to be paid over three years). In February 2012, the parties entered into a services agreement, pursuant to which Vivante agreed to provide support services to MIL. In connection with all of its transactions with Vivante, MIL paid $9.1 million, $6.9 million and $8.6 million to Vivante during fiscal 2015, 2014 and 2013, respectively. As of January 31, 2015, the Company had $3.7 million of liability to Vivante. Dr. Sehat Sutardja and Ms. Dai, through their ownership and control of Estopia LLC, are indirect shareholders of Vivante. In addition, Dr. Sehat Sutardja is also a direct shareholder and Chairman of the board of directors of Vivante. Ms. Dai’s brother (and Dr. Sehat Sutardja’s brother-in-law) is the Chief Executive Officer of Vivante.

Subsequent_Events

Subsequent Events	12 Months Ended
	Jan. 31, 2015
Subsequent Events	Note 15 — Subsequent Events
	On February 25, 2015, the Executive Compensation Committee (“Committee”) of the Company’s Board of Directors approved a cash payment of approximately $15.4 million to Dr. Sehat Sutardja, the Company’s Chief Executive Officer. The U.S. Court of Federal Claims ruled against Dr. Sutardja in his legal challenge with the Internal Revenue Service and the California Franchise Tax Board related to the tax treatment of several stock options granted in fiscal 2004. After discussing and evaluating the alternatives to a continuing legal challenge of the court’s determination, the likelihood of success of further appeal by Dr. Sutardja and the potential negative impact on the Company of a continuation of the case regardless of the outcome, on February 25, 2015, the Committee determined to provide Dr. Sutardja with relief from the financial effects of the penalty taxes. Accordingly, the Committee approved the cash payment to Dr. Sutardja equal to the amount of his penalty taxes owed under the Tax Codes, plus accrued interest owed with respect to such liabilities, all grossed-up for income taxes that will be owed by Dr. Sutardja on receipt of such cash payment. The Company will record the payment in general and administrative expense in the first quarter of fiscal 2016.

Supplementary_Data_Unaudited

Supplementary Data (Unaudited)	12 Months Ended
	Jan. 31, 2015
Supplementary Data (Unaudited)	SUPPLEMENTARY DATA
	(Unaudited)
	The following table presents the unaudited consolidated statements of operations data for each of the eight quarters in the period ended January 31, 2015. In management’s opinion, this information has been presented on the same basis as the audited consolidated financial statements included in a separate section of this Annual Report on Form 10-K, and all necessary adjustments, consisting only of normal recurring adjustments, have been included in the amounts below to fairly state the unaudited quarterly results when read in conjunction with the audited consolidated financial statements and related notes. The operating results for any period should not be considered indicative of results to be expected in any future period. The Company expects the quarterly operating results to fluctuate in future periods due to a variety of reasons, including those discussed in Part I, Item 1A “Risk Factors.”
			Fiscal 2015
			First		Second		Third		Fourth
			Quarter (1)		Quarter (2)		Quarter (3)		Quarter (4)
			(In thousands, except per share amounts)
	Net revenue		$	957,830	$	961,545	$	930,136	$	857,452
	Gross profit		$	463,970	$	483,804	$	475,162	$	440,321
	Net income		$	99,479	$	138,870	$	115,304	$	81,693
	Net income per share:
	Basic		$	0.2	$	0.27	$	0.22	$	0.16
	Diluted		$	0.19	$	0.27	$	0.22	$	0.16
			Fiscal 2014
			First		Second		Third		Fourth
			Quarter		Quarter (5)		Quarter (6)		Quarter (7)
			(In thousands, except per share amounts)
	Net revenue		$	734,369	$	807,056	$	931,226	$	931,749
	Gross profit		$	398,931	$	420,997	$	466,245	$	454,497
	Net income		$	53,209	$	61,826	$	103,156	$	97,129
	Net income per share:
	Basic		$	0.11	$	0.13	$	0.21	$	0.2
	Diluted		$	0.11	$	0.12	$	0.21	$	0.19
	-1	The first quarter of fiscal 2015 includes $8.5 million of restructuring and other exit-related cost that includes a $3.4 million write off of IPR&D.
	-2	The second quarter of fiscal 2015 includes an $8.8 million gain from the sale of an investment and $2.2 million of costs associated with the surety bond to appeal the CMU judgment.
	-3	The third quarter of fiscal 2015 includes $2.3 million of costs associated with the surety bond to appeal the CMU judgment.
	-4	The fourth quarter of fiscal 2015 includes $3.4 million of restructuring and other exit-related cost, and $2.8 million of costs associated with the surety bond to appeal the CMU judgment.
	-5	The second quarter of fiscal 2014 includes $5.2 million for litigation settlements that do not relate to the litigation with CMU.
	-6	The third quarter of fiscal 2014 includes $4.2 million of restructuring and other exit-related costs.
	-7	The fourth quarter of fiscal 2014 includes $9.5 million for anticipated litigation settlements that do not relate to the litigation with CMU, $8.1 million charge for the impairment of an intangible asset and a $7.0 million gain from the sale of a business.

Schedule_ii_Valuation_and_Qual

Schedule ii Valuation and Qualifying Accounts	12 Months Ended
	Jan. 31, 2015
Schedule ii Valuation and Qualifying Accounts	SCHEDULE II
	VALUATION AND QUALIFYING ACCOUNTS
	(in thousands)
		Balance at		Additions		Deductions			Balance at
		Beginning							End of
		of Year							Year
	Fiscal year ended January 31, 2015
	Allowance for doubtful accounts and sales return reserve	$	2,294	$	3,041	$	(3,223	)	$	2,112
	Deferred tax valuation allowance	$	335,890	$	46,906	$	—		$	382,796
	Fiscal year ended February 1, 2014
	Allowance for doubtful accounts and sales return reserve	$	7,921	$	3,808	$	(9,435	)	$	2,294
	Deferred tax valuation allowance	$	299,449	$	36,441	$	—		$	335,890
	Fiscal year ended February 2, 2013
	Allowance for doubtful accounts and sales return reserve	$	2,663	$	9,024	$	(3,766	)	$	7,921
	Deferred tax valuation allowance	$	259,316	$	40,133	$	—		$	299,449

The_Company_and_its_Significan1

The Company and its Significant Accounting Policies (Policies)	12 Months Ended
	Jan. 31, 2015
Basis of Presentation	Basis of Presentation
	The Company’s fiscal year is the 52- or 53-week period ending on the Saturday closest to January 31. In a 52-week year, each fiscal quarter consists of 13 weeks. The additional week in a 53-week year is added to the fourth quarter, making such quarter consist of 14 weeks. Fiscal 2015 and 2014 each had a 52-week period, and fiscal 2013 had a 53-week period.
Use of Estimates	Use of Estimates
	The preparation of consolidated financial statements in conformity with generally accepted accounting principles in the United States (“GAAP”) requires management to make estimates, judgments and assumptions that affect the reported amounts of assets, liabilities, revenues and expenses, and related disclosure of contingent assets and liabilities. On an ongoing basis, the Company evaluates its estimates, including those related to performance-based compensation, revenue recognition, provisions for sales returns and allowances, inventory excess and obsolescence, investment fair values, goodwill and other intangible assets, restructuring, income taxes, litigation and other contingencies. In addition, the Company uses assumptions when employing the Monte Carlo simulation and Black-Scholes valuation models to calculate the fair value of share-based awards that are granted. Actual results could differ from these estimates, and such differences could affect the results of operations reported in future periods.
Principles of Consolidation	Principles of Consolidation
	The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated. The functional currency of the Company and its subsidiaries is the U.S. dollar.
Cash and Cash Equivalents	Cash and Cash Equivalents
	The Company considers all highly liquid investments with a maturity of three months or less from the date of purchase to be cash equivalents. Cash and cash equivalents consist of cash on deposit with banks, time deposits, U.S. government and agency debt, municipal debt securities, corporate debt securities and money market funds.
Investments	Investments
	The Company’s marketable investments are classified as available-for-sale and are reported at fair value. The Company determines any realized gains or losses on the sale of available-for-sale securities on a specific identification method, and such gains and losses are recorded as a component of interest and other income, net. Unrealized gains and losses of the available-for-sale securities are excluded from earnings and reported as a component of accumulated other comprehensive income. The Company assesses whether an other-than-temporary impairment loss on its available-for-sale securities has occurred due to declines in fair value or other market conditions. Declines in fair value that are considered other-than-temporary are recorded as an impairment of investments in interest and other income, net in the consolidated statements of operations.
	In general, investments with original maturities of greater than 90 days and remaining maturities of less than one year are classified as short-term investments. Investments with maturities beyond one year may also be classified as short-term based on their highly liquid nature and because such investments represent the investment of cash that is available for current operations.
	The Company also has equity investments in privately-held companies. If the Company has the ability to exercise significant influence over the investee, but not control, or if the investee is a partnership type investment, the Company accounts for the investments under the equity method. If the Company does not have the ability to exercise significant influence over the operations of the investee, the Company accounts for the investment under the cost method. Investments in privately-held companies are included in other non-current assets.
Impairment of Investments	Impairment of Investments
	If a debt security’s market value is below amortized cost and the Company either intends to sell the security or it is more likely than not that the Company will be required to sell the security before its anticipated recovery, the Company records an other-than-temporary impairment charge to interest and other income, net in the consolidated statements of operations.
	Investments in privately-held companies are subject to a periodic impairment review. Investments are considered impaired when the fair value is below the investment’s cost basis and the decline in value is judged to be other-than-temporary. This assessment is based on a qualitative and quantitative analysis, including, but not limited to, the investee’s revenue and earnings trends, available cash and liquidity, and the status of the investee’s products and the related market for such products. During fiscal 2014, the Company recorded a charge of $1.5 million to write down equity investments that were considered to be impaired. There were no such charges recorded in fiscal 2015 and 2013.
Derivative Financial Instruments	Derivative Financial Instruments
	The Company accounts for its derivative instruments as either assets or liabilities and carries them at fair value. For derivative instruments that hedge the exposure to variability in expected future cash flows and are designated as cash flow hedges, the effective portion of the gain or loss on the derivative instrument is reported as a component of accumulated other comprehensive income in shareholders’ equity and reclassified into earnings in the same period or periods during which the hedged transaction affects earnings. The ineffective portion of the gain or loss on the derivative instrument is recognized in current earnings. To receive hedge accounting treatment, cash flow hedges must be highly effective in offsetting changes to expected future cash flows on hedged transactions. Derivatives that are not designated as hedges must be adjusted to fair value through earnings.
Concentration of Credit Risk and Significant Customers	Concentration of Credit Risk and Significant Customers
	Financial instruments that potentially subject the Company to a significant concentration of credit risk consist principally of cash equivalents, short-term investments and accounts receivable. Cash, cash equivalents and short-term investments balances are maintained with high-quality financial institutions, the composition and maturities of which are regularly monitored by management. The Company believes that the concentration of credit risk in its trade receivables, which consists of a customer base located primarily in the Asia Pacific Region, is substantially mitigated by the Company’s credit evaluation process, relatively short collection terms and the high level of credit worthiness of its customers. The Company performs ongoing credit evaluations of its customers’ financial conditions and limits the amount of credit extended when deemed necessary based upon payment history and the customer’s current credit worthiness, but generally requires no collateral. The Company regularly reviews the allowance for bad debt and doubtful accounts by considering factors such as historical experience, credit quality, age of the accounts receivable balances and current economic conditions that may affect a customer’s ability to pay.
	The Company’s accounts receivable was concentrated with two customers at January 31, 2015, representing 15% and 14% of gross accounts receivable, respectively, and with one customer at February 1, 2014, representing 13% of gross accounts receivable.
	The allowance for doubtful accounts at January 31, 2015 and February 1, 2014 was $1.2 million and $1.3 million, respectively. Please see “Note 1 – The Company and its Significant Accounting Policies – Revenue Recognition” for additional information on sales returns and allowances.
	Historically, a relatively small number of customers have accounted for a significant portion of the Company’s net revenue. Net revenue from one customer was 20%, 24% and 24% for fiscal 2015, 2014 and 2013, respectively. Net revenue from a second customer was 13%, 12% and 10% for fiscal 2015, 2014 and 2013, respectively. In fiscal 2013, net revenue from a third customer was 10%.
	The Company also had net revenue from one distributor representing 11% and 11% for fiscal 2015 and 2013, respectively. No distributors accounted for 10% or greater of total net revenue in fiscal 2014. The Company continuously monitors the creditworthiness of its distributors and believes these distributors’ sales to diverse end customers and to diverse geographies further serve to mitigate the Company’s exposure to credit risk.
Inventories	Inventories
	Inventory is stated at the lower of cost or market, cost being determined under the first-in, first-out method. The total carrying value of the Company’s inventory is reduced for any difference between cost and estimated market value of inventory that is determined to be excess, obsolete or unsellable inventory based upon assumptions about future demand and market conditions. If actual future demand for the Company’s products is less than currently forecasted, the Company may be required to write inventory down below the current carrying value. Once the carrying value of inventory is reduced, it is maintained until the product to which it relates to is sold or otherwise disposed of. Shipping and handling costs are classified as a component of cost of goods sold in the consolidated statements of operations.
Property and Equipment, Net	Property and Equipment, Net
	Property and equipment, net, are stated at cost less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the assets, which ranges from three to seven years for machinery and equipment, computer software, and furniture and fixtures. Buildings are depreciated over an estimated useful life of 30 years and building improvements are depreciated over estimated useful lives of 15 years. Leasehold improvements are depreciated using the shorter of the remaining lease term or the estimated useful life of the asset.
Goodwill	Goodwill
	Goodwill is recorded when the consideration paid for a business acquisition exceeds the fair value of net tangible and intangible assets acquired. Goodwill is measured and tested for impairment annually or more frequently if the Company believes indicators of impairment exist. The Company first assesses qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount. If the company concludes that it is more likely than not that the fair value of a reporting unit is less than its carrying amount, then a two-step quantitative impairment test is performed. The first step requires comparing the fair value of the reporting unit to its net book value, including goodwill. As the Company has only one reporting unit, the fair value of the reporting unit is determined by taking the market capitalization of the Company as determined through quoted market prices and adjusted for control premiums and other relevant factors. A potential impairment exists if the fair value of the reporting unit is lower than its net book value. The second step of the process is only performed if a potential impairment exists, and it involves determining the difference between the fair value of the reporting unit’s net assets other than goodwill and the fair value of the reporting unit. If the difference is less than the net book value of goodwill, impairment exists and is recorded. In the event that the Company determines that the value of goodwill has become impaired, the Company will record a charge for the amount of impairment during the fiscal quarter in which the determination is made.
Long-Lived Assets and Intangible Assets	Long-Lived Assets and Intangible Assets
	The Company assesses the impairment of long-lived assets and intangible assets whenever events or changes in circumstances indicate that the carrying amount of long-lived assets may not be recoverable. The Company estimates the future cash flows, undiscounted and without interest charges, expected to be generated by the assets from its use or eventual disposition. If the sum of the expected future cash flows is less than the carrying amount of those assets, the Company recognizes an impairment loss based on the excess of the carrying amount over the fair value of the assets. Please see “Note 7 – Goodwill and Acquired Intangible Assets” for further details regarding impairment of acquisition-related identified intangible assets.
	Acquisition-related identified intangible assets are amortized on a straight-line basis over their estimated economic lives. In-process research and development (“IPR&D”) is not amortized until the completion of the related development.
Foreign Currency Transactions	Foreign Currency Transactions
	The functional currency of all of the Company’s non-U.S. operations is the U.S. dollar. Monetary accounts maintained in currencies other than the U.S. dollar are re-measured using the foreign exchange rate at the balance sheet date. Operational accounts and nonmonetary balance sheet accounts are measured and recorded at the rate in effect at the date of the transaction. The effects of foreign currency re-measurement are reported in current operations.
Revenue Recognition	Revenue Recognition
	The Company recognizes revenue when there is persuasive evidence of an arrangement, delivery has occurred, the fee is fixed or determinable, and collection is reasonably assured.
	Product revenue is generally recognized upon shipment of product to customers, net of accruals for estimated sales returns and rebates. However, some of the Company’s sales are made through distributors under agreements allowing for price protection, shipped from stock pricing adjustment rights, and limited rights of stock rotation on products unsold by the distributors. Although title passes to the distributor upon shipment terms and payment by the Company’s distributors is not contingent on resale of the product, product revenue on sales made through distributors with price protection, shipped from stock pricing adjustment rights and stock rotation rights are deferred until the distributors sell the product to end customers. Deferred revenue less the related cost of the inventories is reported as deferred income. The Company does not believe that there is any significant exposure related to impairment of deferred cost of sales, as its historical returns have been minimal and inventory turnover for its distributors generally ranges from 60 to 90 days. The Company’s sales to direct customers are made primarily pursuant to standard purchase orders for delivery of products.
	A portion of the Company’s net revenue is derived from sales through third-party logistics providers, who maintain warehouses in close proximity to the customer’s facilities. Revenue from sales through these third-party logistics providers is not recognized until the product is pulled from stock by the end customer.
	The provision for estimated sales returns on product sales is recorded in the same period the related revenues are recorded. These estimates are based on historical returns, analysis of credit memo data and other known factors. Actual returns could differ from these estimates. The Company accounts for rebates by recording reductions to revenue for rebates in the same period that the related revenue is recorded. The amount of these reductions is based upon the terms agreed to with the customer.
Advertising Expense	Advertising Expense
	Advertising costs are expensed as incurred.
Share-Based Compensation	Share-Based Compensation
	Share-based compensation is measured at the grant date, based on the fair value of the award, and is recognized as expense over the requisite service period. The Company amortizes share-based compensation expense for time-based and market-based awards under the straight-line attribution method over the vesting period, which is generally four years for annual grants to employees and five years for new hire grants. Performance-based awards are amortized using the accelerated method. For stock purchase rights under the stock purchase plan, the company amortized share-based compensation expense ratably over the two-year offering period.
	The Company estimates the fair value of time-based stock option and stock purchase awards on the date of grant using the Black Scholes option-pricing model. The fair value of market-based stock option awards is estimated on the date of grant using a Monte Carlo simulation model. The value of the portion of the awards that is ultimately expected to vest is recognized as expense over the requisite service periods. The Black Scholes and Monte Carlo models incorporate various highly subjective assumptions including expected term of awards, expected future stock price volatility and expected forfeiture rates.
	In developing estimates used to calculate assumptions, the Company establishes the expected term for employee stock options, as well as expected forfeiture rates, based on the historical settlement experience and after giving consideration to vesting schedules. Assumptions for stock option exercises and pre-vesting terminations of stock options were stratified by employee groups with sufficiently distinct behavior patterns. Expected volatility was developed based on equally weighted combination of historical stock price volatility and implied volatility derived from traded options on the Company’s stock in the marketplace. The expected dividend yield is calculated by dividing annualized dividend payments by the closing stock price on the grant date of the option.
	Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from initial estimates. Share-based compensation expense is recorded net of estimated forfeitures such that expense is recorded only for those share-based awards that are expected to vest. Previously recognized expense is reversed for the portion of awards forfeited prior to vesting as and when forfeitures occurred.
	The fair value of each restricted stock unit is estimated based on the market price of the Company’s common shares on the date of grant less the expected dividend yield.
Comprehensive Income	Comprehensive Income
	Comprehensive income is comprised of net income and unrealized gains and losses, net of tax, on available-for-sale securities, auction rate securities and cash flow hedges. Accumulated other comprehensive income, as presented on the accompanying balance sheets, consists of net unrealized gains and losses on available-for-sale securities, auction rate securities and cash flow hedges, net of tax.
Accounting for Income Taxes	Accounting for Income Taxes
	The Company recognizes income taxes using an asset and liability approach. This approach requires the recognition of taxes payable or refundable for the current year, and deferred tax liabilities and assets for the future tax consequences of events that have been recognized in the Company’s consolidated financial statements or tax returns. The measurement of current and deferred taxes is based on provisions of the enacted tax law and the effects of future changes in tax laws or rates are not anticipated.
	A valuation allowance must be established for deferred tax assets when it is more likely than not that they will not be realized. Based on the available evidence and judgment, the Company has determined that it is more likely than not that U.S. research credits and certain acquired net operating losses will not be realized and therefore the Company has provided a full valuation allowance against these credits. If there is a change in the Company’s ability to realize its deferred tax assets, then the Company’s tax provision may decrease in the period in which it determines that realization is more likely than not.
	The Company is subject to income tax audits by the respective tax authorities in each jurisdiction in which the Company operates. The Company recognizes the effect of income tax positions only if these positions are more likely than not of being sustained. Recognized income tax positions are measured at the largest amount that is more than 50% likely of being realized. Changes in recognition or measurement are reflected in the period in which the change in judgment occurs. The Company records interest and penalties related to unrecognized tax benefits in income tax expense.
Warranty	Warranty
	The Company’s products are generally subject to warranty, which provides for the estimated future costs of repair, replacement or customer accommodation upon shipment of the product. The Company’s products carry a standard 90 day warranty, with certain exceptions in which the warranty period can extend to more than one year based on contractual agreements. The warranty accrual is primarily estimated based on historical claims compared to historical revenues and assumes that the Company will have to replace products subject to a claim. From time to time, the Company becomes aware of specific warranty situations, and it records specific accruals to cover these exposures.
Recent Accounting Pronouncements	Recent Accounting Pronouncements
	Accounting Pronouncements Recently Adopted
	In July 2013, the Financial Accounting Standards Board (“FASB”) issued an amendment to the accounting guidance related to the financial statement presentation of an unrecognized tax benefit. The guidance requires an unrecognized tax benefit, or a portion of an unrecognized tax benefit, to be presented in the financial statements as a reduction to a deferred tax asset when a net operating loss carryforward, a similar tax loss or a tax credit carryforward is available at the reporting date. The Company adopted this guidance in fiscal 2015 on a prospective basis and presented a portion of its unrecognized tax benefits as a reduction of its deferred tax assets on the face of the consolidated balance sheet as of January 31, 2015. See also “Note 9 — Income Taxes” in the Notes to the Consolidated Financial Statements.”
Accounting Pronouncements Not Yet Effective	Accounting Pronouncements Not Yet Effective
	In April 2014, the FASB issued an amendment to its guidance regarding the reporting requirements of discontinued operations. Under this amended guidance, a discontinued operation is defined as a disposal of a component or group of components that is disposed of or is classified as held for sale and represents a strategic shift that has (or will have) a major effect on an entity’s operations and financial results. In addition, this amendment requires an entity to present, for each comparative period, the assets and liabilities of a disposal group that includes a discontinued operation separately in the asset and liability sections, respectively, of the statement of financial position and additional disclosures about discontinued operations. This amended guidance is effective for annual and interim reporting periods beginning after December 15, 2014. The Company expects this guidance to have an impact on its financial statements only in the event of a future disposition which meets the criteria.
	In May 2014, the FASB issued a new standard on the recognition of revenue from contracts with customers, which will supersede nearly all existing revenue recognition guidance under GAAP. The core principal of the standard is that an entity should recognize revenue when a customer has control of promised goods or services in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. It also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, and assets recognized from costs incurred to obtain or fulfill a contract, including significant judgments and changes in judgments. This standard is effective for annual and interim reporting periods beginning after December 15, 2016 and will be effective for the Company’s first quarter of fiscal 2018. Early adoption is not permitted. The standard allows for either full retrospective or modified retrospective adoption. The Company is evaluating the transition method that will be elected and the potential effects of adoption on its financial statements.

Investments_Tables

Investments (Tables)	12 Months Ended
	Jan. 31, 2015
Schedule of Available-for-sale Securities Reconciliation	The following tables summarize the Company’s investments (in thousands):
		As of January 31, 2015
		Amortized			Gross			Gross			Estimated
		Cost			Unrealized			Unrealized			Fair Value
					Gains			Losses
	Short-term investments:
	Available-for-sale:
	Corporate debt securities	$	983,008		$	3,872		$	(563	)	$	986,317
	U.S. government and agency debt		178,898			265			(7	)		179,156
	Asset backed securities		91,432			108			(9	)		91,531
	Foreign government and agency debt		28,051			61			(2	)		28,110
	Municipal debt securities		33,421			47			(4	)		33,464
	Total short-term investments		1,314,810			4,353			(585	)		1,318,578
	Long-term investments:
	Available-for-sale:
	Auction rate securities		12,500			—			(2,274	)		10,226
	Total long-term investments		12,500			—			(2,274	)		10,226
	Total investments	$	1,327,310		$	4,353		$	(2,859	)	$	1,328,804
		As of February 1, 2014
		Amortized			Gross			Gross			Estimated
		Cost			Unrealized			Unrealized			Fair Value
					Gains			Losses
	Short-term investments:
	Available-for-sale:
	Corporate debt securities	$	587,095		$	2,789		$	(370	)	$	589,514
	U.S. government and agency debt		301,423			128			(72	)		301,479
	Asset backed securities		76,220			89			(38	)		76,271
	Foreign government and agency debt		20,324			12			(44	)		20,292
	Municipal debt securities		16,059			44			(4	)		16,099
	Total short-term investments		1,001,121			3,062			(528	)		1,003,655
	Long-term investments:
	Available-for-sale:
	Auction rate securities		19,150			—			(2,871	)		16,279
	Total long-term investments		19,150			—			(2,871	)		16,279
	Total investments	$	1,020,271		$	3,062		$	(3,399	)	$	1,019,934
Gross Realized Gains and Losses on Sale of Available-for-Sales Securities	Gross realized gains and gross realized losses on sales of available-for-sales securities are presented in the following table (in thousands):
		Year Ended
		January 31,			February 1,			February 2,
		2015			2014			2013
	Gross realized gains	$	1,618		$	1,567		$	3,557
	Gross realized losses		(169	)		(268	)		(319	)
	Total net realized gains	$	1,449		$	1,299		$	3,238
Investments Classified by Contractual Maturity Date	The contractual maturities of available-for-sale securities are presented in the following table (in thousands):
		January 31, 2015						February 1, 2014
		Amortized			Estimated			Amortized			Estimated
		Cost			Fair Value			Cost			Fair Value
	Due in one year or less	$	361,108		$	361,396		$	309,543		$	309,861
	Due between one and five years		950,702			954,151			686,062			688,280
	Due over five years		15,500			13,257			24,666			21,793
		$	1,327,310		$	1,328,804		$	1,020,271		$	1,019,934
Unrealized Loss Position Investments	For individual securities that have been in a continuous unrealized loss position, the fair value and gross unrealized loss for these securities aggregated by investment category and length of time in an unrealized position are presented in the following tables (in thousands):
		January 31, 2015
		Less than 12 months						12 months or more						Total
		Fair			Unrealized			Fair			Unrealized			Fair		Unrealized
		Value			Loss			Value			Loss			Value		Loss
	Corporate debt securities	$	243,699		$	(558	)	$	2,005		$	(5	)	$	245,704	$	(563	)
	U.S. government and agency debt		32,165			(7	)		—			—			32,165		(7	)
	Asset backed securities		25,053			(9	)		—			—			25,053		(9	)
	Foreign government and agency debt		2,999			(2	)		—			—			2,999		(2	)
	Municipal debt securities		2,845			(4	)		—			—			2,845		(4	)
	Auction rate securities		—			—			10,226			(2,274	)		10,226		(2,274	)
	Total securities	$	306,761		$	(580	)	$	12,231		$	(2,279	)	$	318,992	$	(2,859	)
		February 1, 2014
		Less than 12 months						12 months or more						Total
		Fair			Unrealized			Fair			Unrealized			Fair		Unrealized
		Value			Loss			Value			Loss			Value		Loss
	Corporate debt securities	$	110,903		$	(366	)	$	2,105		$	(4	)	$	113,008	$	(370	)
	U.S. government and agency debt		93,118			(72	)		—			—			93,118		(72	)
	Asset backed securities		18,865			(19	)		1,912			(19	)		20,777		(38	)
	Foreign government and agency debt		14,299			(44	)		—			—			14,299		(44	)
	Municipal debt securities		723			(4	)		—			—			723		(4	)
	Auction rate securities		—			—			16,279			(2,871	)		16,279		(2,871	)
	Total securities	$	237,908		$	(505	)	$	20,296		$	(2,894	)	$	258,204	$	(3,399	)

Supplemental_Financial_Informa1

Supplemental Financial Information (Tables)	12 Months Ended
	Jan. 31, 2015
Schedule of Cash and Cash Equivalents
		January 31,			February 1,
		2015			2014
	Cash and cash equivalents:
	Cash	$	864,680		$	694,789
	Cash equivalents:
	Time deposits		213,012			247,958
	U.S. government and agency debt		—			11,999
	Municipal debt securities		—			4,800
	Corporate debt securities		21,999			3,400
	Money market funds		111,286			2,804
	Cash and cash equivalents	$	1,210,977		$	965,750
Schedule of Inventory, Current
		January 31,			February 1,
		2015			2014
	Inventories:
	Work-in-process	$	183,869		$	195,495
	Finished goods		124,293			152,366
	Inventories	$	308,162		$	347,861
Property, Plant and Equipment
		January 31,			February 1,
		2015			2014
	Property and equipment, net:
	Machinery and equipment	$	601,961		$	562,038
	Buildings		144,320			144,320
	Computer software		99,312			96,096
	Land		53,373			53,373
	Building improvements		49,753			49,645
	Leasehold improvements		51,434			49,060
	Furniture and fixtures		27,883			27,621
	Construction in progress		6,167			2,911
			1,034,203			985,064
	Less: Accumulated depreciation		(693,564	)		(628,899	)
	Property and equipment, net	$	340,639		$	356,165
Schedule of Other Assets, Noncurrent
		January 31,			February 1,
		2015			2014
	Other non-current assets:
	Technology and other licenses	$	61,217		$	83,521
	Deferred tax assets		22,273			19,282
	Investments in privately-held companies		9,267			14,565
	Prepaid land use rights		13,432			13,744
	Deposits		7,903			12,433
	Other		14,747			16,821
	Other non-current assets	$	128,839		$	160,366
Schedule of Accrued Liabilities
		January 31,			February 1,
		2015			2014
	Accrued liabilities:
	Accrued rebates	$	39,105		$	61,616
	Accrued royalties		24,680			36,568
	Technology license obligations		14,428			18,482
	Accrued legal expense		10,027			14,589
	Other		43,148			30,507
	Accrued liabilities	$	131,388		$	161,762
Other Noncurrent Liabilities
		January 31,			February 1,
		2015			2014
	Other non-current liabilities:
	Technology license obligations	$	16,468		$	28,959
	Long-term accrued employee compensation		4,610			4,370
	Other		11,115			9,140
	Other non-current liabilities	$	32,193		$	42,469
Changes in Accumulated Other Comprehensive Income by Component	The changes in accumulated other comprehensive income by components are presented in the following tables (in thousands):
		Unrealized			Unrealized			Unrealized			Total
		Gain			Loss on			Gain
		(Loss) on			Auction			(Loss) on
		Marketable			Rate			Cash Flow
		Securities			Securities			Hedges
	Balance at February 1, 2014	$	2,534		$	(2,871	)	$	934		$	597
	Other comprehensive income (loss) before reclassifications		2,479			85			(2,338	)		226
	Amounts reclassified from accumulated other comprehensive income		(1,245	)		512			218			(515	)
	Net current-period other comprehensive income (loss)		1,234			597			(2,120	)		(289	)
	Balance at January 31, 2015	$	3,768		$	(2,274	)	$	(1,186	)	$	308
		Unrealized			Unrealized			Unrealized			Total
		Gain			Loss on			Gain
		(Loss) on			Auction			(Loss) on
		Marketable			Rate			Cash Flow
		Securities			Securities			Hedges
	Balance at February 2, 2013	$	2,742		$	(2,681	)	$	1,087		$	1,148
	Other comprehensive income (loss) before reclassifications		931			(190	)		3,466			4,207
	Amounts reclassified from accumulated other comprehensive income		(1,139	)		—			(3,619	)		(4,758	)
	Net current-period other comprehensive loss		(208	)		(190	)		(153	)		(551	)
	Balance at February 1, 2014	$	2,534		$	(2,871	)	$	934		$	597
Amounts Reclassified from Accumulated Other Comprehensive Income by Components	The amounts reclassified from accumulated other comprehensive income by components are presented in the following table (in thousands):
		Year Ended
	Affected Line Item in the	January 31,			February 1,			February 2,
	Statement of Operations	2015			2014			2013
	Interest and other income, net:
	Available-for-sale securities:
	Marketable securities	$	1,245		$	1,139		$	3,101
	Auction rate securities		(512	)		—			—
	Cash flow hedges:
	Research and development		(198	)		3,329			(2,283	)
	Selling and marketing		(8	)		266			(135	)
	General and administrative		(12	)		24			(77	)
	Total	$	515		$	4,758		$	606
Interest and Other Income, Net	Consolidated Statement of Operations
		Year Ended
		January 31,			February 1,			February 2,
		2015			2014			2013
	Interest and other income, net:
	Interest income	$	11,370			9,379			12,357
	Realized gain on investments		1,449			1,299			3,238
	Currency translation gain (loss)		1,871			8,739			(1,908	)
	Other income		9,811			8,025			2,409
	Interest expense		(1,167	)		(1,876	)		(563	)
		$	23,334		$	25,566		$	15,533
Schedule of Calculation of Numerator and Denominator in Earnings Per Share	The computations of basic and diluted net income per share are presented in the following table (in thousands, except per share amounts):
		Year Ended
		January 31,			February 1,			February 2,
		2015			2014			2013
	Numerator:
	Net income	$	435,346		$	315,320		$	306,585
	Denominator:
	Weighted average shares — basic		511,089			496,518			555,310
	Effect of dilutive securities:
	Share-based awards		9,671			7,895			7,813
	Weighted average shares — diluted		520,760			504,413			563,123
	Net income per share:
	Basic	$	0.85		$	0.64		$	0.55
	Diluted	$	0.84		$	0.63		$	0.54
	Anti-dilutive potential shares are presented in the following table (in thousands, except per share amounts):
		Year Ended
		January 31,			February 1,			February 2,
		2015			2014			2013
	Weighted average shares outstanding from stock options:
	Time-based options		22,485			36,882			25,133
	Market-based options		2,288			2,711			2,991
			24,773			39,593			28,124
	Weighted average exercise price:
	Time-based options	$	17.58		$	15.12		$	17.72
	Market-based options	$	15.43		$	15.43		$	15.43
	Total	$	17.38		$	15.14		$	17.48

Derivative_Financial_Instrumen1

Derivative Financial Instruments (Tables)	12 Months Ended
	Jan. 31, 2015
Schedule of Derivative Instruments	The notional amounts of outstanding forward contracts were as follows (in thousands):
		Buy Contracts
		January 31,				February 1,
		2015				2014
	Israeli shekel	$	51,326			$	39,670
	Euro		—				5,718
	Swedish krona		—				3,709
		$	51,326			$	49,097
Information about Gains (Losses) Associated with Derivative Financial Instruments	The following table provides information about gains (losses) associated with our derivative financial instruments (in thousands):
		Location of		Amount of Gains (Losses) in Statement
		Gains (Losses)		of Operations for the year ended
		Location of Gains (Losses)
		in Statement of Operations		January 31,				February 1,		February 2,
				2015				2014		2013
	Derivatives designated as cash flow hedges:
	Forward contracts:	Research and development		$	(1,930	)		$	3,099	$	(1,909	)
		Selling and marketing			(24	)			23		(13	)
		General and administrative			(157	)			246		(155	)
				$	(2,111	)		$	3,368	$	(2,077	)

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Jan. 31, 2015
Fair Value, Assets Measured on Recurring Basis	The tables below set forth, by level, the Company’s financial assets that were accounted for at fair value as of January 31, 2015 and February 1, 2014. The tables do not include assets and liabilities that are measured at historical cost or any basis other than fair value (in thousands):
		Fair Value Measurements at January 31, 2015
		Level 1			Level 2		Level 3		Total
	Items measured at fair value on a recurring basis:
	Assets
	Cash equivalents:
	Money market funds	$	111,286		$	—	$	—	$	111,286
	Time deposits		—			213,012		—		213,012
	Corporate debt securities		—			21,999		—		21,999
	Short-term investments:
	U.S. government and agency debt		179,156			—		—		179,156
	Corporate debt securities		—			986,317		—		986,317
	Asset backed securities		—			91,531		—		91,531
	Foreign government and agency debt		—			28,110		—		28,110
	Municipal debt securities		—			33,464		—		33,464
	Prepaid expenses and other current assets:
	Foreign currency forward contracts		—			124		—		124
	Long-term investments:
	Auction rate securities		—			—		10,226		10,226
	Other non-current assets:
	Severance pay fund		—			1,758		—		1,758
	Total assets	$	290,442		$	1,376,315	$	10,226	$	1,676,983
	Liabilities
	Accrued liabilities:
	Foreign currency forward contracts	$	—		$	1,379	$	—	$	1,379
		Fair Value Measurements at February 1, 2014
		Level 1			Level 2		Level 3		Total
	Items measured at fair value on a recurring basis:
	Assets
	Cash equivalents:
	Money market funds	$	2,804		$	—	$	—	$	2,804
	Time deposits		—			247,958		—		247,958
	Municipal debt securities		—			4,800		—		4,800
	U.S. government and agency debt		11,999					—		11,999
	Corporate debt securities		—			3,400		—		3,400
	Short-term investments:
	U.S. government and agency debt		301,479			—		—		301,479
	Corporate debt securities		—			589,514		—		589,514
	Asset backed securities		—			76,271		—		76,271
	Foreign government and agency debt		—			20,292		—		20,292
	Municipal debt securities		—			16,099		—		16,099
	Prepaid expenses and other current assets:
	Foreign currency forward contracts		—			1,012		—		1,012
	Long-term investments:
	Auction rate securities		—			—		16,279		16,279
	Other non-current assets:
	Severance pay fund		—			2,193		—		2,193
	Total assets	$	316,282		$	961,539	$	16,279	$	1,294,100
	Liabilities
	Accrued liabilities:
	Foreign currency forward contracts	$	—		$	26	$	—	$	26
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation	The following table summarizes the change in fair values for Level 3 assets for the year ended January 31, 2015 and February 1, 2014 (in thousands):
		Level 3
	Changes in fair value during the year (pre-tax):
	Ending balance at February 2, 2013	$	16,769
	Sales, redemption and settlement		(300	)
	Unrealized loss included in accumulated other comprehensive income		(190	)
	Ending balance at February 1, 2014		16,279
	Sales, redemption and settlement		(3,650	)
	Transfer Out		(3,000	)
	Unrealized loss included in accumulated other comprehensive income		597
	Ending balance at January 31, 2015	$	10,226

Goodwill_and_Acquired_Intangib1

Goodwill and Acquired Intangible Assets (Tables)	12 Months Ended
	Jan. 31, 2015
Summary of Activity Related to Goodwill	The following table summarizes the activity related to the carrying value of goodwill (in thousands):
	Balance at February 2, 2013	$	2,032,138
	Additions due to business combinations		400
	Sale of a business		(2,593	)
	Balance at February 1, 2014	$	2,029,945
	Balance at January 31, 2015	$	2,029,945
Schedule of Finite-Lived Intangible Assets by Major Class	The carrying amounts of acquired intangible assets are as follows (in thousands):
					January 31, 2015							February 1, 2014
		Range of			Gross		Accumulated			Net		Gross		Accumulated			Net
		Useful Lives			Carrying		Amortization			Carrying		Carrying		Amortization			Carrying
					Amounts		and			Amounts		Amounts		and			Amounts
							Write-Offs							Write-Offs
	Purchased technology		4 - 7 years		$	35,498	$	(15,684	)	$	19,814	$	49,240	$	(20,634	)	$	28,606
	Core technology		5 - 8 years			850		(423	)		427		2,350		(1,583	)		767
	Trade names		5 years			1,300		(828	)		472		1,300		(568	)		732
	Customer intangibles		5 - 7 years			28,600		(18,615	)		9,985		28,600		(13,056	)		15,544
	IPR&D		*			—		—			—		3,386		—			3,386
	Total acquired intangible assets, net				$	66,248	$	(35,550	)	$	30,698	$	84,876	$	(35,841	)	$	49,035
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	Based on the identified intangible assets recorded at January 31, 2015, the future amortization expense of identified intangibles excluding IPR&D for the next five fiscal years is as follows (in thousands):
	Fiscal Year
	2016	$	12,212
	2017		11,027
	2018		5,599
	2019		1,860
	2020		—
		$	30,698

Restructuring_Tables

Restructuring (Tables)	12 Months Ended
	Jan. 31, 2015
Schedule of Restructuring Reserve by Type of Cost	The following table presents detail of the related restructuring charges recorded by the Company (in thousands):
		Year Ended
		January 31,			February 1,			February 2,
		2015			2014			2013
	Severance and related costs	$	5,181		$	2,786		$	—
	Facilities and related costs		1,924			1,672			1,257
	Loss on early contract termination		3,230			—			—
	Other exit-related costs		86			213			—
			10,421			4,671			1,257
	Write-off of assets:
	Equipment		17			61			—
	Acquired intangible asset		3,386			—			—
		$	13,824		$	4,732		$	1,257
	The following table presents details of restructuring charges by functional line item (in thousands):
		Year Ended
		January 31,			February 1,			February 2,
		2015			2014			2013
	Research and development	$	5,249		$	2,886		$	47
	Selling and marketing		—			795			(3	)
	General and administrative		5,189			1,051			1,213
	Write-off of acquired intangible assets		3,386			—			—
		$	13,824		$	4,732		$	1,257
Reconciliation of Beginning and Ending Restructuring Liability Balances by Major Type of Costs	The following table sets forth a reconciliation of the beginning and ending restructuring liability balances by each major type of costs associated with the restructuring charges (in thousands):
		Severance			Facilities			Other			Total
		and Related			and Related			Exit-Related
		Costs			Costs			Costs
	Balance at February 2, 2013	$	—		$	2,855		$	—		$	2,855
	Restructuring charges		2,786			1,672			213			4,671
	Net cash payments		(2,735	)		(2,144	)		(194	)		(5,073	)
	Balance at February 1, 2014		51			2,383			19			2,453
	Restructuring charges		5,181			1,924			3,316			10,421
	Net cash payments		(5,232	)		(2,968	)		(105	)		(8,305	)
	Balance at January 31, 2015	$	—		$	1,339		$	3,230		$	4,569

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Jan. 31, 2015
Schedule of US and non US Components of Income Before Income Tax Expense (Benefit)	The U.S. and non-U.S. components of income before income taxes consist of the following (in thousands):
		Year Ended
		January 31,			February 1,			February 2,
		2015			2014			2013
	U.S. operations	$	31,942		$	31,339		$	34,900
	Non-U.S. operations		400,211			274,918			275,290
		$	432,153		$	306,257		$	310,190
Schedule of Components of Income Tax Expense (Benefit)	The provision (benefit) for income taxes consists of the following (in thousands):
		Year Ended
		January 31,			February 1,			February 2,
		2015			2014			2013
	Current income tax provision (benefit):
	Federal	$	9,096		$	5,774		$	4,461
	State		(161	)		73			407
	Foreign		785			(18,829	)		(8,289	)
	Total current income tax provision (benefit)		9,720			(12,982	)		(3,421	)
	Deferred income tax provision (benefit):
	Federal		(1,775	)		317			6,306
	State		16			32			90
	Foreign		(11,154	)		3,570			630
	Total deferred income tax provision (benefit)		(12,913	)		3,919			7,026
	Total provision (benefit) for income taxes	$	(3,193	)	$	(9,063	)	$	3,605
Schedule of Deferred Tax Assets and Liabilities	Deferred tax assets consist of the following (in thousands):
		January 31,			February 1,
		2015			2014
	Deferred tax assets:
	Federal and California research and other tax credits	$	382,726		$	335,894
	Reserves and accruals		35,538			25,833
	Share-based compensation		4,502			4,067
	Net operating losses		14,940			18,470
	Gross deferred tax assets		437,706			384,264
	Valuation allowance		(382,796	)		(335,890	)
	Total deferred tax assets		54,910			48,374
	Total deferred tax liabilities		(11,209	)		(17,586	)
	Net deferred tax assets	$	43,701		$	30,788
Reconciliation of United States Statutory Federal Tax Rate	Reconciliation of the statutory federal income tax to the Company’s effective tax:
		Year Ended
		January 31,			February 1,			February 2,
		2015			2014			2013
	Provision at U.S. notional statutory rate		35	%		35	%		35	%
	Non-deductible share-based compensation		11.2			19.4			15.4
	Difference in U.S. and non-U.S. tax rates		(46.0	)		(55.8	)		(48.8	)
	Benefits from utilization of general business credits		(12.0	)		(14.1	)		(13.8	)
	Change in valuation allowance		10.5			11.9			12.9
	Other		0.6			0.6			0.5
	Effective tax rate		(0.7	)%		(3.0	)%		1.2	%
Unrecognized Tax Benefits Reconciliation	The following table reflects changes in the unrecognized tax benefits (in thousands):
		Year Ended
		January 31,			February 1,			February 2,
		2015			2014			2013
	Unrecognized tax benefits as the beginning of the period	$	51,682		$	79,031		$	96,294
	Increases related to prior year tax positions		976			499			1,106
	Decreases related to prior year tax positions		(386	)		(111	)		—
	Increases related to current year tax positions		5,356			2,666			1,139
	Settlements		—			(7,423	)		(3,956	)
	Lapse in the statute of limitations		(10,691	)		(13,969	)		(15,543	)
	Foreign exchange gain		(1,740	)		(9,011	)		(9	)
	Gross amounts of unrecognized tax benefits as of the end of the period	$	45,197		$	51,682		$	79,031

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Jan. 31, 2015
Future Minimum Lease Payments, Net of Estimated Sublease Income under Operating and Capital Leases	Future minimum lease payments, net of estimated sublease, and payments under technology license obligations as of January 31, 2015, are presented in the following tables (in thousands):
	Fiscal Year:	Minimum
		Operating
		Leases
		Payments
	2016	$	71,489
	2017		42,320
	2018		12,609
	2019		2,700
	2020		2,672
	Thereafter		3,722
	Total future minimum lease payments	$	135,512
Future Minimum Lease Payments Under Technology License Obligations
	Fiscal Year:	Technology
		License
		Obligations
	2016	$	13,145
	2017		7,869
	2018		9,180
	2019		—
	2020		—
	Thereafter		—
	Total future minimum lease payments	$	30,194
	Less: amount representing interest		(1,236	)
	Present value of future minimum payments		28,958
	Less: current portion		(12,490	)
	Non-current portion	$	16,468

Shareholders_Equity_Tables

Shareholders' Equity (Tables)	12 Months Ended
	Jan. 31, 2015
Disclosure of Share-based Compensation Arrangements by Share-based Payment Award	Stock option activity under the Company’s stock option and stock incentive plans is included in the following table (in thousands, except for per share amounts):
			Time-Based Options						Market-Based Options						Total
			Options			Weighted			Options			Weighted			Options			Weighted
			Outstanding			Average			Outstanding			Average			Outstanding			Average
						Exercise						Exercise						Exercise
						Price						Price						Price
	Balance at January 28, 2012			52,467		$	12.53			3,124		$	15.43			55,591		$	12.7
	Granted			7,041		$	14.59			—			—			7,041		$	14.59
	Exercised			(5,977	)	$	6.44			—			—			(5,977	)	$	6.44
	Canceled/Forfeited			(3,894	)	$	16.1			(365	)	$	15.43			(4,259	)	$	16.04
	Balance at February 2, 2013			49,637		$	13.28			2,759		$	15.43			52,396		$	13.39
	Granted			18,922		$	10.82			—			—			18,922		$	10.82
	Exercised			(15,482	)	$	9.4			—			—			(15,482	)	$	9.4
	Canceled/Forfeited			(3,921	)	$	15.15			(136	)	$	15.43			(4,057	)	$	15.16
	Balance at February 1, 2014			49,156		$	13.4			2,623		$	15.43			51,779		$	13.51
	Granted			6,365		$	15.33			—			—			6,365		$	15.33
	Exercised			(3,732	)	$	10.19			—			—			(3,732	)	$	10.19
	Canceled/Forfeited			(4,649	)	$	14.66			(391	)	$	15.43			(5,040	)	$	14.72
	Balance at January 31, 2015			47,140		$	13.79			2,232		$	15.43			49,372		$	13.88
	Vested or expected to vest at January 31, 2015			44,470		$	13.84
	Exercisable at January 31, 2015			22,457		$	15.31
Schedule of Nonvested Share Activity	Activity related to the non-vested portion of the restricted stock units is included in the following table (in thousands, except for share prices):
			Time-Based						Performance-Based						Total
			Number of			Weighted			Number of			Weighted			Number of			Weighted
			Shares			Average			Shares			Average			Shares			Average
						Grant  Date						Grant Date						Grant Date
						Fair Value						Fair Value						Fair Value
	Balance at January 28, 2012			9,646		$	17.38
	Granted			7,370		$	14.64
	Vested			(2,796	)	$	17.78
	Canceled/Forfeited			(1,481	)	$	17.16
	Balance at February 2, 2013			12,739		$	15.78
	Granted			3,728		$	10.79			100		$	10.52			3,828		$	10.78
	Vested			(3,925	)	$	16.19			—		$	—			—		$	—
	Canceled/Forfeited			(1,288	)	$	14.39			—		$	—			—		$	—
	Balance at February 1, 2014			11,254		$	14.14			100		$	10.52			11,354		$	14.11
	Granted			5,534		$	15.2			1,277	*	$	14.98	*		6,811		$	15.16
	Vested			(5,938	)	$	13.96			(3	)	$	10.52			(5,941	)	$	13.96
	Canceled/Forfeited			(1,102	)	$	14.32			(120	)	$	11.23			(1,222	)	$	14.02
	Balance at January 31, 2015			9,748		$	14.84			1,254		$	14.99			11,002		$	14.85
	*	Amounts represent the target number of restricted stock units at grant date. For awards granted to our executive officers, up to 200% of the target restricted stock units may vest if the maximum level for financial and strategic goals is achieved.
Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs	The following table presents details of share-based compensation expenses by functional line item (in thousands):
			Year Ended
			January 31,			February 1,			February 2,
			2015			2014			2013
	Cost of goods sold		$	7,972		$	8,863		$	8,142
	Research and development			94,432			109,432			87,149
	Selling and marketing			11,469			13,940			13,278
	General and administrative			23,373			23,638			18,711
			$	137,246		$	155,873		$	127,280
Schedule of Cash Dividends
			Year Ended
			January 31,			February 1,			February 2,
			2015			2014			2013
	Cash dividend per share		$	0.24		$	0.24		$	0.18
	Total payment to shareholders (in thousands)		$	122,801		$	119,449		$	98,761
Employee Stock Purchase Plan
Weighted Average Assumptions Used to Calculate Fair Value Awards
			Year Ended
			January 31,			February 1,			February 2,
			2015			2014			2013
	Employee Stock Purchase Plan:
	Estimated fair value		$	4.1		$	3.65		$	3.13
	Expected volatility			30	%		37	%		40	%
	Expected term (in years)			1.3			1.3			1.2
	Risk-free interest rate			0.3	%		0.2	%		0.2	%
	Expected dividend yield			1.6	%		2	%		2.4
Time Based Option Award
Weighted Average Assumptions Used to Calculate Fair Value Awards	The following weighted average assumptions were used for each respective period to calculate the fair value of each time-based equity award on the date of grant using the Black-Scholes option pricing model and of each market-based equity award using a Monte Carlo simulation model:
			Year Ended
			January 31,			February 1,			February 2,
			2015			2014			2013
	Time-based Stock Options:
	Weighted average fair value		$	4.35		$	3.43		$	5.52
	Expected volatility			35	%		45	%		44	%
	Expected term (in years)			5			5			4.8
	Risk-free interest rate			1.6	%		0.8	%		0.9	%
	Expected dividend yield			1.6	%		2.4	%		0.3

Segment_and_Geographic_Informa1

Segment and Geographic Information (Tables)	12 Months Ended
	Jan. 31, 2015
Net Revenue and Long-Lived Asset Information based on Geographic Region	The following tables present net revenue and long-lived asset information based on geographic region. Net revenue is based on the destination of the shipments and long-lived assets are based on the physical location of the assets (in thousands):
		Year Ended
	Net Revenue:	January 31,		February 1,		February 2,
		2015		2014		2013
	United States	$	62,333	$	68,321	$	176,581
	China		2,214,876		1,869,381		1,599,681
	Thailand		294,706		353,363		369,855
	Malaysia		377,903		352,756		351,401
	Philippines		254,381		257,899		246,269
	Others		502,764		502,680		424,843
		$	3,706,963	$	3,404,400	$	3,168,630
	Property and equipment, net:	January 31,		February 1,
		2015		2014
	Bermuda	$	3,358	$	4,453
	China		25,910		29,146
	Israel		26,728		33,758
	Singapore		79,216		76,367
	United States		186,321		195,253
	Others		19,106		17,188
		$	340,639	$	356,165
Net Revenue by End Market	The following table presents net revenue by end market (in thousands):
		Year Ended
	Net Revenue by End Market	January 31,		February 1,		February 2,
		2015		2014		2013
	Storage	$	1,744,656	$	1,681,953	$	1,494,959
	Mobile and Wireless		1,071,777		839,407		822,533
	Networking		674,701		670,249		708,821
	Other		215,829		212,791		142,317
		$	3,706,963	$	3,404,400	$	3,168,630

Supplementary_Data_Unaudited_T

Supplementary Data (Unaudited) (Tables)	12 Months Ended
	Jan. 31, 2015
Schedule of Quarterly Financial Information	The following table presents the unaudited consolidated statements of operations data for each of the eight quarters in the period ended January 31, 2015. In management’s opinion, this information has been presented on the same basis as the audited consolidated financial statements included in a separate section of this Annual Report on Form 10-K, and all necessary adjustments, consisting only of normal recurring adjustments, have been included in the amounts below to fairly state the unaudited quarterly results when read in conjunction with the audited consolidated financial statements and related notes. The operating results for any period should not be considered indicative of results to be expected in any future period. The Company expects the quarterly operating results to fluctuate in future periods due to a variety of reasons, including those discussed in Part I, Item 1A “Risk Factors.”
			Fiscal 2015
			First		Second		Third		Fourth
			Quarter (1)		Quarter (2)		Quarter (3)		Quarter (4)
			(In thousands, except per share amounts)
	Net revenue		$	957,830	$	961,545	$	930,136	$	857,452
	Gross profit		$	463,970	$	483,804	$	475,162	$	440,321
	Net income		$	99,479	$	138,870	$	115,304	$	81,693
	Net income per share:
	Basic		$	0.2	$	0.27	$	0.22	$	0.16
	Diluted		$	0.19	$	0.27	$	0.22	$	0.16
			Fiscal 2014
			First		Second		Third		Fourth
			Quarter		Quarter (5)		Quarter (6)		Quarter (7)
			(In thousands, except per share amounts)
	Net revenue		$	734,369	$	807,056	$	931,226	$	931,749
	Gross profit		$	398,931	$	420,997	$	466,245	$	454,497
	Net income		$	53,209	$	61,826	$	103,156	$	97,129
	Net income per share:
	Basic		$	0.11	$	0.13	$	0.21	$	0.2
	Diluted		$	0.11	$	0.12	$	0.21	$	0.19
	-1	The first quarter of fiscal 2015 includes $8.5 million of restructuring and other exit-related cost that includes a $3.4 million write off of IPR&D.
	-2	The second quarter of fiscal 2015 includes an $8.8 million gain from the sale of an investment and $2.2 million of costs associated with the surety bond to appeal the CMU judgment.
	-3	The third quarter of fiscal 2015 includes $2.3 million of costs associated with the surety bond to appeal the CMU judgment.
	-4	The fourth quarter of fiscal 2015 includes $3.4 million of restructuring and other exit-related cost, and $2.8 million of costs associated with the surety bond to appeal the CMU judgment.
	-5	The second quarter of fiscal 2014 includes $5.2 million for litigation settlements that do not relate to the litigation with CMU.
	-6	The third quarter of fiscal 2014 includes $4.2 million of restructuring and other exit-related costs.
	-7	The fourth quarter of fiscal 2014 includes $9.5 million for anticipated litigation settlements that do not relate to the litigation with CMU, $8.1 million charge for the impairment of an intangible asset and a $7.0 million gain from the sale of a business.

Recovered_Sheet1

The Company and Its Significant Accounting Policies - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013	Jan. 02, 2013
	Entity	Entity		Entity
Significant Accounting Policies [Line Items]
Write down of equity investments that were considered to be impaired	$0	$1.50	$0
Allowance for doubtful accounts	$1.20	$1.30
Number of distributors with more than 10% revenue	1	0		1
Net Revenue percentage from distributor representing more than 10% revenue	11.00%			11.00%
Inventory turnover period, minimum (in days)	60 days
Inventory turnover period, maximum (in days)	90 days
Minimum likelihood that uncertain tax position will be sustained as a result of examination by income tax audits	50.00%
Standard Product Warranty Time Period	90 days
Typical Cases
Significant Accounting Policies [Line Items]
Standard Product Warranty Time Period	90 days
Non-Typical Cases | Minimum
Significant Accounting Policies [Line Items]
Standard Product Warranty Time Period	1 year
Buildings
Significant Accounting Policies [Line Items]
Property and equipment, estimated useful lives (in years)	30 years
Building improvements
Significant Accounting Policies [Line Items]
Property and equipment, estimated useful lives (in years)	15 years
Machinery and equipment | Minimum
Significant Accounting Policies [Line Items]
Property and equipment, estimated useful lives (in years)	3 years
Machinery and equipment | Maximum
Significant Accounting Policies [Line Items]
Property and equipment, estimated useful lives (in years)	7 years
Computer software | Minimum
Significant Accounting Policies [Line Items]
Property and equipment, estimated useful lives (in years)	3 years
Computer software | Maximum
Significant Accounting Policies [Line Items]
Property and equipment, estimated useful lives (in years)	7 years
Furniture and fixtures | Minimum
Significant Accounting Policies [Line Items]
Property and equipment, estimated useful lives (in years)	3 years
Furniture and fixtures | Maximum
Significant Accounting Policies [Line Items]
Property and equipment, estimated useful lives (in years)	7 years
Annual Grant
Significant Accounting Policies [Line Items]
Share-based compensation, vest term (in years)	4 years
New Hire
Significant Accounting Policies [Line Items]
Share-based compensation, vest term (in years)	5 years
Stock Purchase Rights
Significant Accounting Policies [Line Items]
Share-based compensation, offering period (in years)	2 years
Credit Concentration Risk | Accounts Receivable
Significant Accounting Policies [Line Items]
Number of major customers	2	1
Concentration of risk percentage		13.00%
Credit Concentration Risk | Accounts Receivable | Customer A
Significant Accounting Policies [Line Items]
Concentration of risk percentage	15.00%
Credit Concentration Risk | Accounts Receivable | Customer B
Significant Accounting Policies [Line Items]
Concentration of risk percentage	14.00%
Customer Concentration Risk | Net Revenue | Customer A
Significant Accounting Policies [Line Items]
Concentration of risk percentage	20.00%	24.00%		24.00%
Customer Concentration Risk | Net Revenue | Customer B
Significant Accounting Policies [Line Items]
Concentration of risk percentage	13.00%	12.00%		10.00%
Customer Concentration Risk | Net Revenue | Customer C
Significant Accounting Policies [Line Items]
Concentration of risk percentage				10.00%
Short-term Investments | Minimum
Significant Accounting Policies [Line Items]
Maturity period to classify investments	90 days
Short-term Investments | Maximum
Significant Accounting Policies [Line Items]
Maturity period to classify investments	1 year

Acquisitions_and_Divestitures_

Acquisitions and Divestitures - Additional Information (Detail) (USD $)	12 Months Ended
	Jan. 31, 2015	Feb. 01, 2014
Business Acquisition [Line Items]
Goodwill written off	$0	$2,593,000
Gain (Loss) on sale of business		6,975,000
Discontinued Operation Or Asset Disposals
Business Acquisition [Line Items]
Intellectual property and equipment	100,000
Goodwill written off	2,600,000
Gain (Loss) on sale of business	$7,000,000

Summary_of_Investments_Detail

Summary of Investments (Detail) (USD $)	Jan. 31, 2015	Feb. 01, 2014
In Thousands, unless otherwise specified
Gain (Loss) on Investments [Line Items]
Amortized Cost	$1,327,310	$1,020,271
Gross Unrealized Gains	4,353	3,062
Gross Unrealized Losses	-2,859	-3,399
Estimated Fair Value	1,328,804	1,019,934
Short-term Investments
Gain (Loss) on Investments [Line Items]
Amortized Cost	1,314,810	1,001,121
Gross Unrealized Gains	4,353	3,062
Gross Unrealized Losses	-585	-528
Estimated Fair Value	1,318,578	1,003,655
Short-term Investments | Corporate debt securities
Gain (Loss) on Investments [Line Items]
Amortized Cost	983,008	587,095
Gross Unrealized Gains	3,872	2,789
Gross Unrealized Losses	-563	-370
Estimated Fair Value	986,317	589,514
Short-term Investments | U.S. government and agency debt
Gain (Loss) on Investments [Line Items]
Amortized Cost	178,898	301,423
Gross Unrealized Gains	265	128
Gross Unrealized Losses	-7	-72
Estimated Fair Value	179,156	301,479
Short-term Investments | Asset-backed Securities
Gain (Loss) on Investments [Line Items]
Amortized Cost	91,432	76,220
Gross Unrealized Gains	108	89
Gross Unrealized Losses	-9	-38
Estimated Fair Value	91,531	76,271
Short-term Investments | Foreign government and agency debt
Gain (Loss) on Investments [Line Items]
Amortized Cost	28,051	20,324
Gross Unrealized Gains	61	12
Gross Unrealized Losses	-2	-44
Estimated Fair Value	28,110	20,292
Short-term Investments | Municipal debt securities
Gain (Loss) on Investments [Line Items]
Amortized Cost	33,421	16,059
Gross Unrealized Gains	47	44
Gross Unrealized Losses	-4	-4
Estimated Fair Value	33,464	16,099
Long-term investments
Gain (Loss) on Investments [Line Items]
Amortized Cost	12,500	19,150
Gross Unrealized Losses	-2,274	-2,871
Estimated Fair Value	10,226	16,279
Long-term investments | Auction rate securities
Gain (Loss) on Investments [Line Items]
Amortized Cost	12,500	19,150
Gross Unrealized Losses	-2,274	-2,871
Estimated Fair Value	$10,226	$16,279

Investments_Additional_Informa

Investments - Additional Information (Detail) (USD $)	Jan. 31, 2015	Feb. 01, 2014
Gain (Loss) on Investments [Line Items]
Amortized Cost	$1,327,310,000	$1,020,271,000
Gross Unrealized Losses	2,859,000	3,399,000
Cash, cash equivalents and short-term investments	2,500,000,000
Long-term investments
Gain (Loss) on Investments [Line Items]
Amortized Cost	12,500,000	19,150,000
Gross Unrealized Losses	2,274,000	2,871,000
Long-term investments | Auction rate securities
Gain (Loss) on Investments [Line Items]
Amortized Cost	12,500,000	19,150,000
Gross Unrealized Losses	$2,274,000	$2,871,000

Gross_Realized_Gains_and_Losse

Gross Realized Gains and Losses on Sale of Available-for-Sales Securities (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013
Schedule of Available-for-sale Securities [Line Items]
Gross realized gains	$1,618	$1,567	$3,557
Gross realized losses	-169	-268	-319
Total net realized gains	$1,449	$1,299	$3,238

Contractual_Maturities_of_Avai

Contractual Maturities of Available for Sale Securities (Detail) (USD $)	Jan. 31, 2015	Feb. 01, 2014
In Thousands, unless otherwise specified
Amortized Cost
Due in one year or less	$361,108	$309,543
Due between one and five years	950,702	686,062
Due over five years	15,500	24,666
Amortized Cost	1,327,310	1,020,271
Estimated Fair Value
Due in one year or less	361,396	309,861
Due between one and five years	954,151	688,280
Due over five years	13,257	21,793
Estimated Fair Value	$1,328,804	$1,019,934

Summary_of_Investments_Gross_U

Summary of Investments Gross Unrealized Losses and Fair Value (Detail) (USD $)	Jan. 31, 2015	Feb. 01, 2014
In Thousands, unless otherwise specified
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	$306,761	$237,908
Less than 12 months Unrealized Losses	-580	-505
12 months or more Fair Value	12,231	20,296
12 months or more Unrealized Losses	-2,279	-2,894
Total Fair Value	318,992	258,204
Total Unrealized Losses	-2,859	-3,399
Corporate debt securities
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	243,699	110,903
Less than 12 months Unrealized Losses	-558	-366
12 months or more Fair Value	2,005	2,105
12 months or more Unrealized Losses	-5	-4
Total Fair Value	245,704	113,008
Total Unrealized Losses	-563	-370
U.S. government and agency debt
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	32,165	93,118
Less than 12 months Unrealized Losses	-7	-72
Total Fair Value	32,165	93,118
Total Unrealized Losses	-7	-72
Asset-backed Securities
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	25,053	18,865
Less than 12 months Unrealized Losses	-9	-19
12 months or more Fair Value		1,912
12 months or more Unrealized Losses		-19
Total Fair Value	25,053	20,777
Total Unrealized Losses	-9	-38
Foreign government and agency debt
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	2,999	14,299
Less than 12 months Unrealized Losses	-2	-44
Total Fair Value	2,999	14,299
Total Unrealized Losses	-2	-44
Municipal debt securities
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair Value	2,845	723
Less than 12 months Unrealized Losses	-4	-4
Total Fair Value	2,845	723
Total Unrealized Losses	-4	-4
Auction rate securities
Investments, Unrealized Loss Position [Line Items]
12 months or more Fair Value	10,226	16,279
12 months or more Unrealized Losses	-2,274	-2,871
Total Fair Value	10,226	16,279
Total Unrealized Losses	($2,274)	($2,871)

Cash_and_Cash_Equivalents_Deta

Cash and Cash Equivalents (Detail) (USD $)	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013	Jan. 28, 2012
In Thousands, unless otherwise specified
Cash, cash equivalents and marketable securities [Line Items]
Cash	$864,680	$694,789
Cash equivalents:
Time deposits	213,012	247,958
U.S. government and agency debt		11,999
Municipal debt securities		4,800
Corporate debt securities	21,999	3,400
Money market funds	111,286	2,804
Cash and cash equivalents	$1,210,977	$965,750	$751,953	$784,902

Inventories_Detail

Inventories (Detail) (USD $)	Jan. 31, 2015	Feb. 01, 2014
In Thousands, unless otherwise specified
Inventory [Line Items]
Work-in-process	$183,869	$195,495
Finished goods	124,293	152,366
Inventories	$308,162	$347,861

Property_and_Equipment_Net_Det

Property and Equipment Net (Detail) (USD $)	Jan. 31, 2015	Feb. 01, 2014
In Thousands, unless otherwise specified
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$1,034,203	$985,064
Less: Accumulated depreciation	-693,564	-628,899
Property and equipment, net	340,639	356,165
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	601,961	562,038
Buildings
Property, Plant and Equipment [Line Items]
Property and equipment, gross	144,320	144,320
Computer software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	99,312	96,096
Land
Property, Plant and Equipment [Line Items]
Property and equipment, gross	53,373	53,373
Building improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	49,753	49,645
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	51,434	49,060
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	27,883	27,621
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$6,167	$2,911

Supplemental_Financial_Informa2

Supplemental Financial Information - Additional Information (Detail) (USD $)	12 Months Ended
	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013
Additional Financial Information [Line Items]
Depreciation expense	$78,300,000	$77,200,000	$70,700,000
Amortization expense	16,397,000	43,925,000	52,700,000
Technology and Other Licenses
Additional Financial Information [Line Items]
Amortization expense	$27,900,000	$25,600,000	$20,300,000

Other_Non_Current_Assets_Detai

Other Non Current Assets (Detail) (USD $)	Jan. 31, 2015	Feb. 01, 2014
In Thousands, unless otherwise specified
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Line Items]
Technology and other licenses	$61,217	$83,521
Deferred tax assets	22,273	19,282
Investments in privately-held companies	9,267	14,565
Prepaid land use rights	13,432	13,744
Deposits	7,903	12,433
Other	14,747	16,821
Other non-current assets	$128,839	$160,366

Accrued_Liabilities_Detail

Accrued Liabilities (Detail) (USD $)	Jan. 31, 2015	Feb. 01, 2014
In Thousands, unless otherwise specified
Schedule of Accrued Liabilities [Line Items]
Accrued rebates	$39,105	$61,616
Accrued royalties	24,680	36,568
Technology license obligations	14,428	18,482
Accrued legal expense	10,027	14,589
Other	43,148	30,507
Accrued liabilities	$131,388	$161,762

Other_Long_Term_Liabilities_De

Other Long Term Liabilities (Detail) (USD $)	Jan. 31, 2015	Feb. 01, 2014
In Thousands, unless otherwise specified
Schedule of Other Liabilities [Line Items]
Technology license obligations	$16,468	$28,959
Long-term accrued employee compensation	4,610	4,370
Other	11,115	9,140
Other non-current liabilities	$32,193	$42,469

Changes_in_Accumulated_Other_C

Changes in Accumulated Other Comprehensive Income by Component (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$597	$1,148
Other comprehensive income (loss) before reclassifications	226	4,207
Amounts reclassified from accumulated other comprehensive income	-515	-4,758
Net current-period other comprehensive income (loss)	-289	-551	372
Ending Balance	308	597	1,148
Unrealized Gain (Loss) on Marketable Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	2,534	2,742
Other comprehensive income (loss) before reclassifications	2,479	931
Amounts reclassified from accumulated other comprehensive income	-1,245	-1,139
Net current-period other comprehensive income (loss)	1,234	-208
Ending Balance	3,768	2,534
Unrealized(Loss) on Auction Rate Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	-2,871	-2,681
Other comprehensive income (loss) before reclassifications	85	-190
Amounts reclassified from accumulated other comprehensive income	512
Net current-period other comprehensive income (loss)	597	-190
Ending Balance	-2,274	-2,871
Unrealized Gain (Loss) on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	934	1,087
Other comprehensive income (loss) before reclassifications	-2,338	3,466
Amounts reclassified from accumulated other comprehensive income	218	-3,619
Net current-period other comprehensive income (loss)	-2,120	-153
Ending Balance	($1,186)	$934

Amounts_Reclassified_from_Accu

Amounts Reclassified from Accumulated Other Comprehensive Income by Components (Detail) (USD $)	3 Months Ended															12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015		Nov. 01, 2014		Aug. 02, 2014		3-May-14		Feb. 01, 2014		Nov. 02, 2013		Aug. 03, 2013		4-May-13	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest and other income, net																$23,334	$25,566	$15,533
Research and development																-1,164,059	-1,156,885	-1,057,445
Selling and marketing																-143,952	-152,698	-161,817
General and administrative																-130,030	-106,471	-108,514
Net income	81,693	[1]	115,304	[2]	138,870	[3]	99,479	[4]	97,129	[5]	103,156	[6]	61,826	[7]	53,209	435,346	315,320	306,585
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income																515	4,758	606
Reclassification out of Accumulated Other Comprehensive Income | Unrealized Gain (Loss) on Marketable Securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest and other income, net																1,245	1,139	3,101
Reclassification out of Accumulated Other Comprehensive Income | Unrealized Gain (Loss) on Cash Flow Hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Research and development																-198	3,329	-2,283
Selling and marketing																-8	266	-135
General and administrative																-12	24	-77
Reclassification out of Accumulated Other Comprehensive Income | Unrealized(Loss) on Auction Rate Securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest and other income, net																($512)
[1]	The fourth quarter of fiscal 2015 includes $3.4 million of restructuring and other exit-related cost, and $2.8 million of costs associated with the surety bond to appeal the CMU judgment.
[2]	The third quarter of fiscal 2015 includes $2.3 million of costs associated with the surety bond to appeal the CMU judgment.
[3]	The second quarter of fiscal 2015 includes an $8.8 million gain from the sale of an investment and $2.2 million of costs associated with the surety bond to appeal the CMU judgment.
[4]	The first quarter of fiscal 2015 includes $8.5 million of restructuring and other exit-related cost that includes a $3.4 million write off of IPR&D.
[5]	The fourth quarter of fiscal 2014 includes $9.5 million for anticipated litigation settlements that do not relate to the litigation with CMU, $8.1 million charge for the impairment of an intangible asset and a $7.0 million gain from the sale of a business.
[6]	The third quarter of fiscal 2014 includes $4.2 million of restructuring and other exit-related costs.
[7]	The second quarter of fiscal 2014 includes $5.2 million for litigation settlements that do not relate to the litigation with CMU.

Interest_and_Other_Income_Net_

Interest and Other Income Net (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013
Interest and Other Income [Line Items]
Interest income	$11,370	$9,379	$12,357
Realized gain on investments	1,449	1,299	3,238
Currency translation gain (loss)	1,871	8,739	-1,908
Other income	9,811	8,025	2,409
Interest expense	-1,167	-1,876	-563
Interest and other income, net	$23,334	$25,566	$15,533

Computations_of_Basic_and_Dilu

Computations of Basic and Diluted Net Income Per Share (Detail) (USD $)	3 Months Ended															12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jan. 31, 2015		Nov. 01, 2014		Aug. 02, 2014		3-May-14		Feb. 01, 2014		Nov. 02, 2013		Aug. 03, 2013		4-May-13	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013
Numerator:
Net income	$81,693	[1]	$115,304	[2]	$138,870	[3]	$99,479	[4]	$97,129	[5]	$103,156	[6]	$61,826	[7]	$53,209	$435,346	$315,320	$306,585
Denominator:
Weighted average shares - basic																511,089	496,518	555,310
Effect of dilutive securities:
Share-based awards																9,671	7,895	7,813
Weighted average shares - diluted																520,760	504,413	563,123
Basic	$0.16	[1]	$0.22	[2]	$0.27	[3]	$0.20	[4]	$0.20	[5]	$0.21	[6]	$0.13	[7]	$0.11	$0.85	$0.64	$0.55
Diluted	$0.16	[1]	$0.22	[2]	$0.27	[3]	$0.19	[4]	$0.19	[5]	$0.21	[6]	$0.12	[7]	$0.11	$0.84	$0.63	$0.54
Time-based options
Effect of dilutive securities:
Weighted average shares outstanding from stock options																22,485	36,882	25,133
Weighted average exercise price																$17.58	$15.12	$17.72
Market Based Option Award
Effect of dilutive securities:
Weighted average shares outstanding from stock options																2,288	2,711	2,991
Weighted average exercise price																$15.43	$15.43	$15.43
Stock Options
Effect of dilutive securities:
Weighted average shares outstanding from stock options																24,773	39,593	28,124
Weighted average exercise price																$17.38	$15.14	$17.48
[1]	The fourth quarter of fiscal 2015 includes $3.4 million of restructuring and other exit-related cost, and $2.8 million of costs associated with the surety bond to appeal the CMU judgment.
[2]	The third quarter of fiscal 2015 includes $2.3 million of costs associated with the surety bond to appeal the CMU judgment.
[3]	The second quarter of fiscal 2015 includes an $8.8 million gain from the sale of an investment and $2.2 million of costs associated with the surety bond to appeal the CMU judgment.
[4]	The first quarter of fiscal 2015 includes $8.5 million of restructuring and other exit-related cost that includes a $3.4 million write off of IPR&D.
[5]	The fourth quarter of fiscal 2014 includes $9.5 million for anticipated litigation settlements that do not relate to the litigation with CMU, $8.1 million charge for the impairment of an intangible asset and a $7.0 million gain from the sale of a business.
[6]	The third quarter of fiscal 2014 includes $4.2 million of restructuring and other exit-related costs.
[7]	The second quarter of fiscal 2014 includes $5.2 million for litigation settlements that do not relate to the litigation with CMU.

Notional_Amounts_of_Outstandin

Notional Amounts of Outstanding Foreign Currency Forward Contracts (Detail) (Foreign Exchange Buy Contracts, USD $)	Jan. 31, 2015	Feb. 01, 2014
In Thousands, unless otherwise specified
Derivative [Line Items]
Derivative, notional amount	$51,326	$49,097
Israeli shekel
Derivative [Line Items]
Derivative, notional amount	51,326	39,670
Euro
Derivative [Line Items]
Derivative, notional amount		5,718
Swedish krona
Derivative [Line Items]
Derivative, notional amount		$3,709

Information_about_Gains_Losses

Information about Gains (Losses) Associated with Derivative Financial Instruments (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gains (Losses) in Statement of Operations	($2,111)	$3,368	($2,077)
Cash flow hedges | Foreign currency forward contracts | Research and development
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gains (Losses) in Statement of Operations	-1,930	3,099	-1,909
Cash flow hedges | Foreign currency forward contracts | Selling and marketing
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gains (Losses) in Statement of Operations	-24	23	-13
Cash flow hedges | Foreign currency forward contracts | General and administrative
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gains (Losses) in Statement of Operations	($157)	$246	($155)

Derivative_Financial_Instrumen2

Derivative Financial Instruments - Additional Information (Detail) (USD $)	12 Months Ended
	Jan. 31, 2015	Feb. 01, 2014	Jan. 02, 2013
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Cash flow hedges were terminated as a result of forecasted transactions that did not occur	$0
Not Designated as Hedging Instrument [Member] | Foreign currency forward contracts | Interest and other income, net
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Portion of gains excluded from the assessment of hedge effectiveness	$200,000	$500,000	$400,000

Fair_Value_Measurements_Additi

Fair Value Measurements - Additional Information (Detail)	Jan. 31, 2015
Fair Value, Measurement Inputs, Disclosure [Line Items]
Percentage of total amount of assets measured using Level 3 valuation methodologies to total assets	0.20%

Financial_Assets_that_were_Acc

Financial Assets that were Accounted for at Fair Value (Detail) (Items measured at fair value, USD $)	Jan. 31, 2015	Feb. 01, 2014
In Thousands, unless otherwise specified
Assets
Total assets	$1,676,983	$1,294,100
Accrued Liabilities | Foreign currency forward contracts
Liabilities
Accrued liabilities	1,379	26
Cash equivalents | Money market funds
Assets
Cash equivalents	111,286	2,804
Cash equivalents | Time deposits
Assets
Cash equivalents	213,012	247,958
Cash equivalents | Municipal debt securities
Assets
Cash equivalents		4,800
Cash equivalents | U.S. government and agency debt
Assets
Cash equivalents		11,999
Cash equivalents | Corporate debt securities
Assets
Cash equivalents	21,999	3,400
Short-term Investments | Municipal debt securities
Assets
Investments	33,464	16,099
Short-term Investments | U.S. government and agency debt
Assets
Investments	179,156	301,479
Short-term Investments | Corporate debt securities
Assets
Investments	986,317	589,514
Short-term Investments | Asset-backed Securities
Assets
Investments	91,531	76,271
Short-term Investments | Foreign government and agency debt
Assets
Investments	28,110	20,292
Prepaid expenses and other current assets | Foreign currency forward contracts
Assets
Prepaid expenses and other current assets	124	1,012
Long-term investments | Auction rate securities
Assets
Investments	10,226	16,279
Other non-current assets | Severance Pay Fund
Assets
Other non-current asset	1,758	2,193
Level 1
Assets
Total assets	290,442	316,282
Level 1 | Cash equivalents | Money market funds
Assets
Cash equivalents	111,286	2,804
Level 1 | Cash equivalents | U.S. government and agency debt
Assets
Cash equivalents		11,999
Level 1 | Short-term Investments | U.S. government and agency debt
Assets
Investments	179,156	301,479
Level 2
Assets
Total assets	1,376,315	961,539
Level 2 | Accrued Liabilities | Foreign currency forward contracts
Liabilities
Accrued liabilities	1,379	26
Level 2 | Cash equivalents | Time deposits
Assets
Cash equivalents	213,012	247,958
Level 2 | Cash equivalents | Municipal debt securities
Assets
Cash equivalents		4,800
Level 2 | Cash equivalents | Corporate debt securities
Assets
Cash equivalents	21,999	3,400
Level 2 | Short-term Investments | Municipal debt securities
Assets
Investments	33,464	16,099
Level 2 | Short-term Investments | Corporate debt securities
Assets
Investments	986,317	589,514
Level 2 | Short-term Investments | Asset-backed Securities
Assets
Investments	91,531	76,271
Level 2 | Short-term Investments | Foreign government and agency debt
Assets
Investments	28,110	20,292
Level 2 | Prepaid expenses and other current assets | Foreign currency forward contracts
Assets
Prepaid expenses and other current assets	124	1,012
Level 2 | Other non-current assets | Severance Pay Fund
Assets
Other non-current asset	1,758	2,193
Level 3
Assets
Total assets	10,226	16,279
Level 3 | Long-term investments | Auction rate securities
Assets
Investments	$10,226	$16,279

Summary_of_Change_in_Fair_Valu

Summary of Change in Fair Values for Level Three Items (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Feb. 01, 2014
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	$16,279	$16,769
Sales, redemption and settlement	-3,650	-300
Transfer Out	-3,000
Unrealized loss included in accumulated other comprehensive income	597	-190
Ending balance	$10,226	$16,279

Goodwill_and_Acquired_Intangib2

Goodwill and Acquired Intangible Assets - Additional Information (Detail) (USD $)	3 Months Ended		12 Months Ended
	3-May-14	Feb. 01, 2014	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013
Goodwill and Intangible Assets Disclosure [Line Items]
Additions to goodwill			$0	$400,000
Impairment of goodwill			0	2,593,000
Write off of acquisition related intangible assets		8,100,000		8,100,000
Write off of acquired IPR&D	$3,400,000		$3,400,000		$800,000

Carrying_Value_of_Goodwill_Det

Carrying Value of Goodwill (Detail) (USD $)	12 Months Ended
	Jan. 31, 2015	Feb. 01, 2014
Goodwill [Line Items]
Beginning balance	$2,029,945,000	$2,032,138,000
Additions due to business combinations	0	400,000
Sale of a business	0	-2,593,000
Ending balance	$2,029,945,000	$2,029,945,000

Acquired_Intangible_Assets_Net

Acquired Intangible Assets Net (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Feb. 01, 2014
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amounts	$66,248	$84,876
Accumulated Amortization and Write-Offs	-35,550	-35,841
Net Carrying Amount	30,698	49,035
In-process research and development
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amounts, Indefinite-Lived		3,386
Accumulated Amortization and Write-Offs, Indefinite-Lived	0	0
Net Carrying Amount, Indefinite-Lived		3,386
Purchased technology
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amounts, Finite-Lived	35,498	49,240
Accumulated Amortization and Write-Offs	-15,684	-20,634
Net Carrying Amount, Finite-Lived	19,814	28,606
Purchased technology | Minimum
Acquired Finite-Lived Intangible Assets [Line Items]
Useful Lives	4 years
Purchased technology | Maximum
Acquired Finite-Lived Intangible Assets [Line Items]
Useful Lives	7 years
Core technology
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amounts, Finite-Lived	850	2,350
Accumulated Amortization and Write-Offs	-423	-1,583
Net Carrying Amount, Finite-Lived	427	767
Core technology | Minimum
Acquired Finite-Lived Intangible Assets [Line Items]
Useful Lives	5 years
Core technology | Maximum
Acquired Finite-Lived Intangible Assets [Line Items]
Useful Lives	8 years
Trade names
Acquired Finite-Lived Intangible Assets [Line Items]
Useful Lives	5 years
Gross Carrying Amounts, Finite-Lived	1,300	1,300
Accumulated Amortization and Write-Offs	-828	-568
Net Carrying Amount, Finite-Lived	472	732
Customer intangibles
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amounts, Finite-Lived	28,600	28,600
Accumulated Amortization and Write-Offs	-18,615	-13,056
Net Carrying Amount, Finite-Lived	$9,985	$15,544
Customer intangibles | Minimum
Acquired Finite-Lived Intangible Assets [Line Items]
Useful Lives	5 years
Customer intangibles | Maximum
Acquired Finite-Lived Intangible Assets [Line Items]
Useful Lives	7 years

Future_Amortization_Expense_of

Future Amortization Expense of Identified Intangibles (Detail) (In Process Research and Development Excluded, USD $)	Jan. 31, 2015
In Thousands, unless otherwise specified
In Process Research and Development Excluded
Fiscal Year
2016	$12,212
2017	11,027
2018	5,599
2019	1,860
2020	0
Net Carrying Amount, Finite-Lived	$30,698

Restructuring_Charges_Detail

Restructuring Charges (Detail) (USD $)	3 Months Ended			12 Months Ended
In Thousands, unless otherwise specified	Aug. 02, 2014	3-May-14	Nov. 02, 2013	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013
Restructuring Cost and Reserve [Line Items]
Restructuring charges				$10,421	$4,671	$1,257
Restructuring charges	8,800	8,500	4,200	13,824	4,732	1,257
Severance and Related Costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges				5,181	2,786
Facilities and Related Costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges				1,924	1,672	1,257
Loss on Early Contract Termination
Restructuring Cost and Reserve [Line Items]
Restructuring charges				3,230
Other Exit-Related Costs
Restructuring Cost and Reserve [Line Items]
Restructuring charges				86	213
Research and development
Restructuring Cost and Reserve [Line Items]
Restructuring charges				5,249	2,886	47
Selling and marketing
Restructuring Cost and Reserve [Line Items]
Restructuring charges					795	-3
General and administrative
Restructuring Cost and Reserve [Line Items]
Restructuring charges				5,189	1,051	1,213
Write-off of acquired intangible assets
Restructuring Cost and Reserve [Line Items]
Restructuring charges				3,386
Equipment
Restructuring Cost and Reserve [Line Items]
Restructuring charges				$17	$61

Reconciliation_of_Beginning_an

Reconciliation of Beginning and Ending Restructuring Liability Balances by Major Type of Costs (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013
Restructuring Cost and Reserve [Line Items]
Restructuring liabilities, beginning of balance	$2,453	$2,855
Restructuring charges	10,421	4,671	1,257
Net cash payments	-8,305	-5,073
Restructuring liabilities, ending balance	4,569	2,453	2,855
Severance Pay Fund
Restructuring Cost and Reserve [Line Items]
Restructuring liabilities, beginning of balance	51
Restructuring charges	5,181	2,786
Net cash payments	-5,232	-2,735
Restructuring liabilities, ending balance		51
Facilities and Related Costs
Restructuring Cost and Reserve [Line Items]
Restructuring liabilities, beginning of balance	2,383	2,855
Restructuring charges	1,924	1,672	1,257
Net cash payments	-2,968	-2,144
Restructuring liabilities, ending balance	1,339	2,383	2,855
Other Exit-Related Costs
Restructuring Cost and Reserve [Line Items]
Restructuring liabilities, beginning of balance	19
Restructuring charges	3,316	213
Net cash payments	-105	-194
Restructuring liabilities, ending balance	$3,230	$19

Restructuring_Additional_Infor

Restructuring - Additional Information (Detail) (Payment Terms Period One)	12 Months Ended
	Jan. 31, 2015
Payment Terms Period One
Restructuring Cost and Reserve [Line Items]
Year of expected payments under lease obligations	2018

US_and_NonUS_Components_of_Inc

U.S. and Non-U.S. Components of Income Before Income Taxes (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013
Schedule of Components of Income Before Income Tax Expense (Benefit) [Line Items]
U.S. operations	$31,942	$31,339	$34,900
Non-U.S. operations	400,211	274,918	275,290
Income before income taxes	$432,153	$306,257	$310,190

provision_Benefit_for_Income_T

provision (Benefit) for Income Taxes (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013
Current income tax provision (benefit):
Federal	$9,096	$5,774	$4,461
State	-161	73	407
Foreign	785	-18,829	-8,289
Total current income tax provision (benefit)	9,720	-12,982	-3,421
Deferred income tax provision (benefit):
Federal	-1,775	317	6,306
State	16	32	90
Foreign	-11,154	3,570	630
Total deferred income tax provision (benefit)	-12,913	3,919	7,026
Total provision (benefit) for income taxes	($3,193)	($9,063)	$3,605

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013
Income Taxes [Line Items]
Current income tax liability	$17,400,000	$13,200,000	$20,100,000
Increase in current unrecognized tax benefits	7,400,000	9,100,000	8,000,000
Reduction in unrecognized tax benefits due to the expiration of statute of limitations	16,400,000	31,800,000	26,800,000
Increase (decrease) in net deferred tax	12,900,000
Deferred tax assets, non-current	22,273,000	19,282,000
Singapore tax holiday expiration date	2019-06
Unrecognized tax benefit that would affect the effective income tax rate if recognized	38,500,000
Unrecognized tax benefit, interest and penalties accrued	27,700,000	29,600,000	33,800,000
Interest and penalties related to unrecognized tax benefits included in consolidated statements of operation	3,800,000	6,200,000	5,800,000
Uncertain tax positions decrease from the lapse of the statutes of limitation in various jurisdictions during the next 12 months	-20,000,000
Cash, Cash Equivalents, and Short-term Investments	2,500,000,000
Undistributed earnings of foreign subsidiaries	400,000,000
Foreign Subsidiaries
Income Taxes [Line Items]
Cash, Cash Equivalents, and Short-term Investments	900,000,000
Increase (decrease) in tax expense in the event of undistributed earnings needed by the parent company or no longer considered indefinitely reinvested outside of Bermuda	100,000,000
Foreign Country
Income Taxes [Line Items]
Net operating loss carryforwards	58,200,000
Net operating loss carryforwards, expiration date	The losses in non-U.S. companies vary; some countries allows the loss be carried forward indefinitely while another allows only 15 years
OperatingLossCarryforwardExpirationPeriod	15 years
California
Income Taxes [Line Items]
Net operating loss carryforwards	7,400,000
California | Minimum
Income Taxes [Line Items]
Net operating loss carryforwards, expiration date	2018
California | Maximum
Income Taxes [Line Items]
Net operating loss carryforwards, expiration date	2033
Economic Development Board of Singapore Pioneer Status
Income Taxes [Line Items]
Expiration of tax exemption	10 years
Tax holidays, tax savings amount	100,000	3,700,000	13,600,000
Economic Development Board of Singapore Pioneer Status | Maximum
Income Taxes [Line Items]
Tax holidays, per share effect on earnings	$0.01	$0.01	$0.02
Economic Development Board of Singapore Pioneer Status | Extended Expiration
Income Taxes [Line Items]
Expiration of tax exemption	15 years
Israeli Law of Approved or Benefited Enterprise
Income Taxes [Line Items]
Tax holidays, tax savings amount	0	2,200,000	13,800,000
Tax holidays, per share effect on earnings	$0	$0.01	$0.02
Swiss Federal Department of Economy and the Vaud Cantonal Tax Administration Tax Holiday
Income Taxes [Line Items]
Expiration of tax exemption	10 years
Tax holidays, tax savings amount	4,500,000	5,100,000	4,600,000
Swiss Federal Department of Economy and the Vaud Cantonal Tax Administration Tax Holiday | Maximum
Income Taxes [Line Items]
Tax holidays, per share effect on earnings	$0.01	$0.01	$0.01
Internal Revenue Service (IRS)
Income Taxes [Line Items]
Net operating loss carryforwards	1,800,000
Internal Revenue Service (IRS) | Minimum
Income Taxes [Line Items]
Net operating loss carryforwards, expiration date	2020
Internal Revenue Service (IRS) | Maximum
Income Taxes [Line Items]
Net operating loss carryforwards, expiration date	2024
Research
Income Taxes [Line Items]
Tax credit carryforwards	382,800,000
Valuation allowance commentary	At the end of fiscal 2015, the Company has provided a full valuation allowance against its federal and various state research credits which it earns in excess of its current year tax liabilities, as well as a portion against its net operating loss carryforwards. Based on the available objective positive and negative evidence, the Company has determined that it is more likely than not that these research credits and acquired net operating losses will not be realized.
Tax credit carryforwards, increase in valuation allowance	46,900,000
Research | California
Income Taxes [Line Items]
Tax credit carryforwards	239,100,000
Tax credit carryforward, expiration dates	Which can be carryforward indefinitely
Net operating loss carryforwards, amount attributable to excess tax benefits from stock options	55,000,000
Research | Internal Revenue Service (IRS)
Income Taxes [Line Items]
Tax credit carryforwards	233,200,000
Net operating loss carryforwards, amount attributable to excess tax benefits from stock options	56,800,000
Research | Internal Revenue Service (IRS) | Maximum
Income Taxes [Line Items]
Tax credit carryforward, expiration dates	2035
Research and Investment | Other State
Income Taxes [Line Items]
Tax credit carryforwards	$20,800,000
Research and Investment | Other State | Maximum
Income Taxes [Line Items]
Tax credit carryforward, expiration dates	2030

Deferred_Tax_Assets_Detail

Deferred Tax Assets (Detail) (USD $)	Jan. 31, 2015	Feb. 01, 2014
In Thousands, unless otherwise specified
Deferred tax assets:
Federal and California research and other tax credits	$382,726	$335,894
Reserves and accruals	35,538	25,833
Share-based compensation	4,502	4,067
Net operating losses	14,940	18,470
Gross deferred tax assets	437,706	384,264
Valuation allowance	-382,796	-335,890
Total deferred tax assets	54,910	48,374
Total deferred tax liabilities	-11,209	-17,586
Net deferred tax assets	$43,701	$30,788

Reconciliation_of_Statutory_Fe

Reconciliation of Statutory Federal Income Tax to Effective Tax (Detail)	12 Months Ended
	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013
Reconciliation of Statutory Federal Tax Rate [Line Items]
Provision at U.S. notional statutory rate	35.00%	35.00%	35.00%
Non-deductible share-based compensation	11.20%	19.40%	15.40%
Difference in U.S. and non-U.S. tax rates	-46.00%	-55.80%	-48.80%
Benefits from utilization of general business credits	-12.00%	-14.10%	-13.80%
Change in valuation allowance	10.50%	11.90%	12.90%
Other	0.60%	0.60%	0.50%
Effective tax rate	-0.70%	-3.00%	1.20%

Changes_in_Unrecognized_Tax_Be

Changes in Unrecognized Tax Benefits (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013
Income Tax Contingency [Line Items]
Unrecognized tax benefits as of the beginning of the period	$51,682	$79,031	$96,294
Increases related to prior year tax positions	976	499	1,106
Decreases related to prior year tax positions	-386	-111
Increases related to current year tax positions	5,356	2,666	1,139
Settlements		-7,423	-3,956
Lapse in the statute of limitations	-10,691	-13,969	-15,543
Foreign exchange gain	-1,740	-9,011	-9
Gross amounts of unrecognized tax benefits as of the end of the period	$45,197	$51,682	$79,031

Commitments_and_Contingencies_1

Commitments and Contingencies - Additional Information (Detail) (USD $)	12 Months Ended			0 Months Ended
In Millions, unless otherwise specified	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013	Mar. 31, 2014	Dec. 26, 2012	Nov. 14, 2014	14-May-14
Commitments and Contingencies Disclosure [Line Items]
Standard warranty period	90 days
Extended warranty period	1 year
Description of extended warranty period	Warranty period can extend to more than one year based on contractual agreements
Rent expense, net of sublease income	$26.10	$25.80	$23.70
Accrued liability related to legal proceedings	3.2
Carrying value of pledged assets	139
Surety Bond
Commitments and Contingencies Disclosure [Line Items]
Bond						216	1,540
Carnegie Mellon Litigation
Commitments and Contingencies Disclosure [Line Items]
Date of lawsuit filed	6-Mar-09
Loss contingency, awarded amount				1,540	1,170
Pre-judgment interest					322
Additional royalties	400
Loss contingency, range of possible loss, minimum	0
Commitment Letter
Commitments and Contingencies Disclosure [Line Items]
Bond						95
Manufacturing Expense
Commitments and Contingencies Disclosure [Line Items]
Purchase commitment, outstanding commitment	$252.10

Future_Minimum_Lease_Payments_

Future Minimum Lease Payments, Net of Estimated Sublease Income under Operating and Capital Leases (Detail) (Minimum Operating Lease Payments, USD $)	Jan. 31, 2015
In Thousands, unless otherwise specified
Minimum Operating Lease Payments
Fiscal Year:
2016	$71,489
2017	42,320
2018	12,609
2019	2,700
2020	2,672
Thereafter	3,722
Total future minimum lease payments	$135,512

Future_Minimum_Payments_Under_

Future Minimum Payments Under Technology License Obligations (Detail) (USD $)	Jan. 31, 2015	Feb. 01, 2014
In Thousands, unless otherwise specified
Fiscal Year:
Less: current portion	($14,428)	($18,482)
Non-current portion	16,468	28,959
Technology License Agreement
Fiscal Year:
2016	13,145
2017	7,869
2018	9,180
2019	0
2020	0
Thereafter	0
Total future minimum lease payments	30,194
Less: amount representing interest	-1,236
Present value of future minimum payments	28,958
Less: current portion	-12,490
Non-current portion	$16,468

Benefit_Plans_Additional_Infor

Benefit Plans - Additional Information (Detail) (USD $)	12 Months Ended
	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013
Defined Contribution Pension Plan 401k
Postemployment Benefits Disclosure [Line Items]
401(k) savings and investment plan, general description of the plan	The Company sponsors a 401(k) savings and investment plan that allows eligible U.S. employees to participate by making pre-tax contributions to the 401(k) plan ranging from 1% to 50% of eligible earnings subject to a required annual limit. The Company matches 100% of the employee contribution up to $500 per eligible employee on a quarterly basis. The participant must be employed by the Company on the last day of the calendar quarter to qualify for the match. At the end of the calendar year, the eligible employees receive a true-up match equal to the accumulated employee contribution for the calendar year up to $2,000.
Defined contribution plan, cost recognized	$5,100,000	$5,100,000	$5,100,000
Employer match contributions percentage	100.00%
Defined Contribution Pension Plan 401k | Minimum
Postemployment Benefits Disclosure [Line Items]
Employee pre-tax contributions to 401(k)	1.00%
Defined Contribution Pension Plan 401k | Maximum
Postemployment Benefits Disclosure [Line Items]
Employee pre-tax contributions to 401(k)	50.00%
Defined Contribution Pension Plan 401k | Quarterly Match | Maximum
Postemployment Benefits Disclosure [Line Items]
Employer match contributions	500
Defined Contribution Pension Plan 401k | Annual True Up Match | Maximum
Postemployment Benefits Disclosure [Line Items]
Employer match contributions	2,000
Defined Contribution Plans Non-U.S Locations
Postemployment Benefits Disclosure [Line Items]
Employer match contributions	$18,600,000	$20,600,000	$17,200,000

Shareholders_Equity_Additional

Shareholders' Equity - Additional Information (Detail) (USD $)	12 Months Ended			0 Months Ended	1 Months Ended	12 Months Ended
	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013	Feb. 19, 2015	Mar. 31, 2015	Jan. 28, 2012	Jan. 30, 2015	Aug. 31, 2010
Stockholders Equity Note [Line Items]
Common stock, shares authorized	992,000,000	992,000,000
Common stock, par value	$0.00	$0.00
Preferred stock, shares authorized	8,000,000	8,000,000
Preferred stock, par value	$0.00	$0.00
Preferred stock, shares outstanding	0	0
Equity awards, vesting percentage	200.00%
Closing stock price							$15.49
Stock-based compensation capitalized in inventory	$1,500,000	$1,700,000	$1,500,000
Shares Granted	6,365,000	18,922,000	7,041,000
Share repurchase program, amount authorized	3,300,000,000							500,000,000
Share repurchase program, additional authorized amount						2,800,000,000
Share repurchase program, shares repurchased	5,100,000	33,100,000	91,000,000
Share repurchase program, amount repurchased	65,000,000	354,100,000	959,100,000
Share repurchase program, cumulative shares repurchased	222,000,000
Share repurchase program, total amount of repurchases	2,800,000,000
Share repurchase program, remaining available for future share repurchases	443,500,000
Dividend per share, declared	$0.24	$0.24	$0.18
Subsequent Event
Stockholders Equity Note [Line Items]
Performance awards vesting Date					1-Apr-15
Share-based Payment Award, shares expected to Vest					478,001
Dividend per share, declared				$0.06
Dividends declared, date to be paid				2-Apr-15
Dividends declared, date of record				12-Mar-15
Time Based Option Award
Stockholders Equity Note [Line Items]
Options vested and expected to vest, aggregate intrinsic value	122,100,000
Options vested and expected to vest, weighted average remaining contractual term (in years)	5 years 10 months 24 days
Options exercisable, aggregate intrinsic value	51,900,000
Options exercisable, weighted average remaining contractual term (in years)	3 years 6 months
Aggregate intrinsic value of stock options exercised	19,300,000	51,100,000	33,600,000
Unrecognized share based compensation cost	53,300,000
Unrecognized share based compensation cost, weighted-average period of recognition	2 years 3 months 18 days
Shares Granted	6,365,000	18,922,000	7,041,000
Expected term (in years)	5 years	5 years	4 years 9 months 18 days
Market Based Option Award
Stockholders Equity Note [Line Items]
Equity awards, expiration term						5 years
Options vested and expected to vest, aggregate intrinsic value	0
Options vested and expected to vest, weighted average remaining contractual term (in years)	6 years 2 months 12 days
Shares Granted	0	0	0			3,100,000
Expected term (in years)						2 years 7 months 28 days
Restricted Stock Units (RSUs)
Stockholders Equity Note [Line Items]
Unrecognized share based compensation cost	87,500,000
Unrecognized share based compensation cost, weighted-average period of recognition	1 year 3 months 18 days
Restricted stock units, aggregate intrinsic value	160,300,000
Restricted stock units vested and expected to vest	10,400,000
Performance Based Restricted Stock Unit | April 1, 2015
Stockholders Equity Note [Line Items]
Performance awards vesting Date	1-Apr-15
Performance Based Restricted Stock Unit | April 1, 2016
Stockholders Equity Note [Line Items]
Performance awards vesting Date	1-Apr-16
Employee Stock Option Plan, 1995 Plan
Stockholders Equity Note [Line Items]
Shares reserved for issuance, authorized	383,400,000
Equity awards, expiration term	10 years
Equity awards, number of installments	4
Number of shares available for future issuance	90,000,000
Employee Stock Option Plan, 1995 Plan | After One Year From Vesting Commencement Date
Stockholders Equity Note [Line Items]
Equity awards, vesting percentage	20.00%
Employee Stock Option Plan, 1995 Plan | Per Month Over Remaining Months
Stockholders Equity Note [Line Items]
Equity awards, vesting percentage	1.67%
Equity awards, vesting term	48 months
Employee Stock Option Plan, 1995 Plan | Incentive Stock Option
Stockholders Equity Note [Line Items]
Equity awards, expiration term	5 years
Stock option, purchase price as percentage of fair market value	110.00%
Employee Stock Option Plan, 1995 Plan | Strategic Performance Award | First Anniversary
Stockholders Equity Note [Line Items]
Equity awards, vesting percentage	50.00%
Employee Stock Option Plan, 1995 Plan | Strategic Performance Award | Second Anniversary
Stockholders Equity Note [Line Items]
Equity awards, vesting percentage	50.00%
Employee Stock Option Plan, 1995 Plan | Financial Performance RSU | First Anniversary
Stockholders Equity Note [Line Items]
Equity awards, vesting percentage	50.00%
Employee Stock Option Plan, 1995 Plan | Financial Performance RSU | Second Anniversary
Stockholders Equity Note [Line Items]
Equity awards, vesting percentage	50.00%
Employee Stock Option Plan, 1995 Plan | Performance Based Restricted Stock Unit
Stockholders Equity Note [Line Items]
Equity awards, vesting term	2 years
Employee Stock Option Plan, 1995 Plan | Performance Based Restricted Stock Unit | April 1, 2015
Stockholders Equity Note [Line Items]
Equity awards, vesting percentage	50.00%
Employee Stock Option Plan, 1995 Plan | Performance Based Restricted Stock Unit | April 1, 2016
Stockholders Equity Note [Line Items]
Equity awards, vesting percentage	50.00%
Directors Stock Option Plan, 1997 Plan
Stockholders Equity Note [Line Items]
Equity awards, expiration term	10 months
Directors Stock Option Plan, 1997 Plan | Upon Appointment To Board of Directors
Stockholders Equity Note [Line Items]
Number of shares authorized to a director	30,000
Directors Stock Option Plan, 1997 Plan | On Date Of Annual Meeting Of Shareholders
Stockholders Equity Note [Line Items]
Number of shares authorized to a director	6,000
Directors Stock Option Plan, 1997 Plan | After One Year From Vesting Commencement Date | Upon Appointment To Board of Directors
Stockholders Equity Note [Line Items]
Equity awards, vesting percentage	20.00%
Directors Stock Option Plan, 1997 Plan | Per Month Over Remaining Months | Upon Appointment To Board of Directors
Stockholders Equity Note [Line Items]
Equity awards, vesting percentage	1.67%
Equity awards, vesting term	48 months
Directors Stock Option Plan, 1997 Plan | Per Month Over 12 Months After Fourth Anniversary of Vesting Commencement Date | On Date Of Annual Meeting Of Shareholders
Stockholders Equity Note [Line Items]
Equity awards, vesting percentage	8.33%
Equity awards, vesting term	12 months
Director Stock Incentive Plan, 2007 Plan
Stockholders Equity Note [Line Items]
Shares reserved for issuance, authorized	750,000
Number of shares available for future issuance	144,692
Director Stock Incentive Plan, 2007 Plan | Upon Appointment To Board of Directors
Stockholders Equity Note [Line Items]
Equity awards, expiration term	10 years
Number of shares authorized to a director	50,000
Director Stock Incentive Plan, 2007 Plan | Upon ReElection By Shareholders
Stockholders Equity Note [Line Items]
Equity awards, expiration term	10 years
Equity awards, vesting percentage	100.00%
Number of shares authorized to a director	9,000
Director Stock Incentive Plan, 2007 Plan | Outside director who was appointed
Stockholders Equity Note [Line Items]
Stock option award		110,000	110,000
Director Stock Incentive Plan, 2007 Plan | First Anniversary Of Grant Date | Upon Appointment To Board of Directors
Stockholders Equity Note [Line Items]
Equity awards, vesting percentage	33.33%
Director Stock Incentive Plan, 2007 Plan | Second Anniversary Of Grant Date and Thereafter | Upon Appointment To Board of Directors
Stockholders Equity Note [Line Items]
Equity awards, vesting percentage	33.33%
Director Stock Incentive Plan, 2007 Plan | Employee Stock Option | Outside director who was appointed
Stockholders Equity Note [Line Items]
Equity awards, expiration term		10 years	10 years
Director Stock Incentive Plan, 2007 Plan | Employee Stock Option | Outside director who was appointed | Maximum
Stockholders Equity Note [Line Items]
Number of shares authorized to a director		25,000
Director Stock Incentive Plan, 2007 Plan | Restricted Stock Units (RSUs)
Stockholders Equity Note [Line Items]
Equity awards, vesting percentage	100.00%
Equity awards, aggregate fair market value	70,000
Director Stock Incentive Plan, 2007 Plan | Restricted Stock Units (RSUs) | Outside director who was appointed
Stockholders Equity Note [Line Items]
Equity awards, vesting percentage		100.00%	100.00%
Equity awards, aggregate fair market value		110,000	110,000
Director Stock Incentive Plan, 2007 Plan | Restricted Stock Units (RSUs) | Outside director who was appointed | Maximum
Stockholders Equity Note [Line Items]
Number of shares authorized to a director		10,000
Director Stock Incentive Plan, 2007 Plan | Restricted Stock Units (RSUs) | Outside director who is first elected or appointed | Fiscal 2015
Stockholders Equity Note [Line Items]
Equity awards, vesting percentage	100.00%
Equity awards, aggregate fair market value	$220,000
Director Stock Incentive Plan, 2007 Plan | Restricted Stock Units (RSUs) | Outside director who is first elected or appointed | Fiscal 2015 | Maximum
Stockholders Equity Note [Line Items]
Number of shares authorized to a director	20,000
Employee Stock Purchase Plan, 2000 Restated Plan
Stockholders Equity Note [Line Items]
Number of shares available for future issuance	14,800,000
Employee stock purchase plan, maximum subscription rate	15.00%
Employee stock purchase plan, "look-back" period	24 months
Employee stock purchase plan, percentage discount of purchase price per share of common shares	85.00%
Employee stock purchase plan, shares issued	9,700,000	9,700,000	7,600,000
Employee stock purchase plan, weighted-average price	$7.67	$7.39	$8.77
Employee Stock Purchase Plan, 2000 Plan
Stockholders Equity Note [Line Items]
Employee stock purchase plan, "look-back" period						6 months

Stock_Option_Plan_Activity_Det

Stock Option Plan Activity (Detail) (USD $)	12 Months Ended
	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013	Jan. 28, 2012
Options Outstanding
Beginning Balance	51,779,000	52,396,000	55,591,000
Granted	6,365,000	18,922,000	7,041,000
Exercised	-3,732,000	-15,482,000	-5,977,000
Canceled/Forfeited	-5,040,000	-4,057,000	-4,259,000
Ending Balance	49,372,000	51,779,000	52,396,000
Weighted Average Exercise Price
Beginning Balance	$13.51	$13.39	$12.70
Granted	$15.33	$10.82	$14.59
Exercised	$10.19	$9.40	$6.44
Canceled/Forfeited	$14.72	$15.16	$16.04
Ending Balance	$13.88	$13.51	$13.39
Time Based Option Award
Options Outstanding
Beginning Balance	49,156,000	49,637,000	52,467,000
Granted	6,365,000	18,922,000	7,041,000
Exercised	-3,732,000	-15,482,000	-5,977,000
Canceled/Forfeited	-4,649,000	-3,921,000	-3,894,000
Ending Balance	47,140,000	49,156,000	49,637,000
Vested or expected to vest at January 31, 2015	44,470,000
Exercisable at January 31, 2015	22,457,000
Weighted Average Exercise Price
Beginning Balance	$13.40	$13.28	$12.53
Granted	$15.33	$10.82	$14.59
Exercised	$10.19	$9.40	$6.44
Canceled/Forfeited	$14.66	$15.15	$16.10
Ending Balance	$13.79	$13.40	$13.28
Vested or expected to vest at January 31, 2015	$13.84
Exercisable at January 31, 2015	$15.31
Market Based Option Award
Options Outstanding
Beginning Balance	2,623,000	2,759,000	3,124,000
Granted	0	0	0	3,100,000
Canceled/Forfeited	-391,000	-136,000	-365,000
Ending Balance	2,232,000	2,623,000	2,759,000	3,124,000
Weighted Average Exercise Price
Beginning Balance	$15.43	$15.43	$15.43
Canceled/Forfeited	$15.43	$15.43	$15.43
Ending Balance	$15.43	$15.43	$15.43	$15.43

Activity_Related_to_Non_Vested

Activity Related to Non Vested Portion of Restricted Stock Units (Detail) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jan. 31, 2015		Feb. 01, 2014	Feb. 02, 2013
Time Based Restricted Units
Restricted Stock Units Outstanding
Beginning Balance	11,254		12,739	9,646
Granted	5,534		3,728	7,370
Vested	-5,938		-3,925	-2,796
Canceled/Forfeited	-1,102		-1,288	-1,481
Ending Balance	9,748		11,254	12,739
Weighted Average Grant Date Fair Value
Beginning Balance	$14.14		$15.78	$17.38
Granted	$15.20		$10.79	$14.64
Vested	$13.96		$16.19	$17.78
Canceled/Forfeited	$14.32		$14.39	$17.16
Ending Balance	$14.84		$14.14	$15.78
Performance Based Restricted Stock Unit
Restricted Stock Units Outstanding
Beginning Balance	100
Granted	1,277	[1]	100
Vested	-3
Canceled/Forfeited	-120
Ending Balance	1,254		100
Weighted Average Grant Date Fair Value
Beginning Balance	$10.52
Granted	$14.98	[1]	$10.52
Vested	$10.52
Canceled/Forfeited	$11.23
Ending Balance	$14.99		$10.52
Restricted Stock Units (RSUs)
Restricted Stock Units Outstanding
Beginning Balance	11,354
Granted	6,811		3,828
Vested	-5,941
Canceled/Forfeited	-1,222
Ending Balance	11,002		11,354
Weighted Average Grant Date Fair Value
Beginning Balance	$14.11
Granted	$15.16		$10.78
Vested	$13.96
Canceled/Forfeited	$14.02
Ending Balance	$14.85		$14.11
[1]	Amounts represent the target number of restricted stock units at grant date. For awards granted to our executive officers, up to 200% of the target restricted stock units may vest if the maximum level for financial and strategic goals is achieved.

Activity_Related_to_Non_Vested1

Activity Related to Non Vested Portion of Restricted Stock Units (Parenthetical) (Detail)	12 Months Ended
	Jan. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock unit vested	200.00%

Total_Stock_Compensation_by_Ex

Total Stock Compensation by Expense (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense	$137,246	$155,873	$127,280
Cost of goods sold
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense	7,972	8,863	8,142
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense	94,432	109,432	87,149
Selling and marketing
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense	11,469	13,940	13,278
General and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation expense	$23,373	$23,638	$18,711

Weighted_Average_Assumptions_U

Weighted Average Assumptions Used to Calculate Fair Value of Time Based Equity Award (Detail) (Time Based Option Award, USD $)	12 Months Ended
	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013
Time Based Option Award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average fair value	$4.35	$3.43	$5.52
Expected volatility	35.00%	45.00%	44.00%
Expected term (in years)	5 years	5 years	4 years 9 months 18 days
Risk-free interest rate	1.60%	0.80%	0.90%
Expected dividend yield	1.60%	2.40%	0.30%

Valuation_Assumptions_Detail

Valuation Assumptions (Detail) (Employee Stock Purchase Plan, USD $)	12 Months Ended
	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated fair value	$4.10	$3.65	$3.13
Expected volatility	30.00%	37.00%	40.00%
Expected term (in years)	1 year 3 months 18 days	1 year 3 months 18 days	1 year 2 months 12 days
Risk-free interest rate	0.30%	0.20%	0.20%
Expected dividend yield	1.60%	2.00%	2.40%

Schedule_of_Cash_Dividends_Det

Schedule of Cash Dividends (Detail) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013
Cash dividend
Cash dividend per share	$0.24	$0.24	$0.18
Total payment to shareholders (in thousands)	$122,801	$119,449	$98,761

Segment_and_Geographic_Informa2

Segment and Geographic Information - Additional Information (Detail)	12 Months Ended
	Jan. 31, 2015
	Segment
Segment Reporting Information [Line Items]
Number of reportable segment	1

Net_Revenue_and_LongLived_Asse

Net Revenue and Long-Lived Asset Information based on Geographic Region (Detail) (USD $)	3 Months Ended															12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015		Nov. 01, 2014		Aug. 02, 2014		3-May-14		Feb. 01, 2014		Nov. 02, 2013		Aug. 03, 2013		4-May-13	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenue	$857,452	[1]	$930,136	[2]	$961,545	[3]	$957,830	[4]	$931,749	[5]	$931,226	[6]	$807,056	[7]	$734,369	$3,706,963	$3,404,400	$3,168,630
Property and equipment, net	340,639								356,165							340,639	356,165
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenue																62,333	68,321	176,581
Property and equipment, net	186,321								195,253							186,321	195,253
China
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenue																2,214,876	1,869,381	1,599,681
Property and equipment, net	25,910								29,146							25,910	29,146
Thailand
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenue																294,706	353,363	369,855
Malaysia
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenue																377,903	352,756	351,401
Philippines
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenue																254,381	257,899	246,269
Others
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenue																502,764	502,680	424,843
Property and equipment, net	19,106								17,188							19,106	17,188
Bermuda
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	3,358								4,453							3,358	4,453
Israel
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	26,728								33,758							26,728	33,758
Singapore
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	$79,216								$76,367							$79,216	$76,367
[1]	The fourth quarter of fiscal 2015 includes $3.4 million of restructuring and other exit-related cost, and $2.8 million of costs associated with the surety bond to appeal the CMU judgment.
[2]	The third quarter of fiscal 2015 includes $2.3 million of costs associated with the surety bond to appeal the CMU judgment.
[3]	The second quarter of fiscal 2015 includes an $8.8 million gain from the sale of an investment and $2.2 million of costs associated with the surety bond to appeal the CMU judgment.
[4]	The first quarter of fiscal 2015 includes $8.5 million of restructuring and other exit-related cost that includes a $3.4 million write off of IPR&D.
[5]	The fourth quarter of fiscal 2014 includes $9.5 million for anticipated litigation settlements that do not relate to the litigation with CMU, $8.1 million charge for the impairment of an intangible asset and a $7.0 million gain from the sale of a business.
[6]	The third quarter of fiscal 2014 includes $4.2 million of restructuring and other exit-related costs.
[7]	The second quarter of fiscal 2014 includes $5.2 million for litigation settlements that do not relate to the litigation with CMU.

Net_Revenue_by_End_Market_Deta

Net Revenue by End Market (Detail) (USD $)

3 Months Ended

12 Months Ended

In Thousands, unless otherwise specified

Jan. 31, 2015

Nov. 01, 2014

Aug. 02, 2014

3-May-14

Feb. 01, 2014

Nov. 02, 2013

Aug. 03, 2013

4-May-13

Jan. 31, 2015

Feb. 01, 2014

Feb. 02, 2013

Revenue from External Customer [Line Items]

Net revenue

$857,452

[1]

$930,136

[2]

$961,545

[3]

$957,830

[4]

$931,749

[5]

$931,226

[6]

$807,056

[7]

$734,369

$3,706,963

$3,404,400

$3,168,630

Storage

Revenue from External Customer [Line Items]

Net revenue

1,744,656

1,681,953

1,494,959

Mobile and Wireless

Revenue from External Customer [Line Items]

Net revenue

1,071,777

839,407

822,533

Networking

Revenue from External Customer [Line Items]

Net revenue

674,701

670,249

708,821

Other products

Revenue from External Customer [Line Items]

Net revenue

$215,829

$212,791

$142,317

[1]

The fourth quarter of fiscal 2015 includes $3.4 million of restructuring and other exit-related cost, and $2.8 million of costs associated with the surety bond to appeal the CMU judgment.

[2]

The third quarter of fiscal 2015 includes $2.3 million of costs associated with the surety bond to appeal the CMU judgment.

[3]

The second quarter of fiscal 2015 includes an $8.8 million gain from the sale of an investment and $2.2 million of costs associated with the surety bond to appeal the CMU judgment.

[4]

The first quarter of fiscal 2015 includes $8.5 million of restructuring and other exit-related cost that includes a $3.4 million write off of IPR&D.

[5]

The fourth quarter of fiscal 2014 includes $9.5 million for anticipated litigation settlements that do not relate to the litigation with CMU, $8.1 million charge for the impairment of an intangible asset and a $7.0 million gain from the sale of a business.

[6]

The third quarter of fiscal 2014 includes $4.2 million of restructuring and other exit-related costs.

[7]

The second quarter of fiscal 2014 includes $5.2 million for litigation settlements that do not relate to the litigation with CMU.

Related_Party_Transactions_Add

Related Party Transactions - Additional Information (Detail) (USD $)	12 Months Ended	1 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Jan. 31, 2015	Dec. 31, 2012	Feb. 01, 2014	Feb. 02, 2013
Related Party Transaction [Line Items]
Technology license agreement, renewed term	3 years
Vivante Corporation | Technology License Agreement
Related Party Transaction [Line Items]
License Agreement	In December 2009, MIL entered into a technology license agreement with Vivante Corporation ("Vivante") that provides for the license of graphics technology and associated services. This agreement restates, expands and succeeds previous agreements between the parties for the same technology.
Vivante Corporation | Restated Technology Agreement
Related Party Transaction [Line Items]
Liability to related party	3.7
Vivante Corporation | Restated Technology Agreement | License Fees
Related Party Transaction [Line Items]
Amount of transactions with related parties		13
Payment period		3 years
Vivante Corporation | Restated Technology Agreement | Support Fees
Related Party Transaction [Line Items]
Payment period		3 years
Maintenance fees		10.00%
Vivante Corporation | Restated Technology Agreement | License and Support Fees
Related Party Transaction [Line Items]
Amount of transactions with related parties	9.1		6.9	8.6
Veri Silicon Holdings Company Limited | Technology License Agreement
Related Party Transaction [Line Items]
License Agreement	MIL is party to a technology license agreement with VeriSilicon Holdings Co., Ltd. (bVeriSiliconb). MIL assumed this technology license agreement between VeriSilicon and UTStarcom, Inc. after the Companybs acquisition of the semiconductor business of UTStarcom in December 2005. MIL has subsequently entered into various addenda to this agreement for additional technology beyond the scope of the original agreement. In addition, in September 2010, MIL entered into a services agreement with VeriSilicon, pursuant to which VeriSilicon has agreed to provide design support services to MIL. Under the services agreement, VeriSilicon helped on three projects for MIL during fiscal 2013.
Liability to related party	0.8
Veri Silicon Holdings Company Limited | Technology License Agreement | License and Support Fees
Related Party Transaction [Line Items]
Amount of transactions with related parties	3.7		$2	$2.80

Subsequent_Events_Additional_I

Subsequent Events - Additional Information (Detail) (Subsequent Event, USD $)	0 Months Ended
In Millions, unless otherwise specified	Feb. 25, 2015
Subsequent Event
Subsequent Event [Line Items]
Cash payment approved for Chief Executive Officer	$15.40

Quarterly_Unaudited_Consolidat

Quarterly Unaudited Consolidated Statements of Operations Data (Detail) (USD $)	3 Months Ended															12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Jan. 31, 2015		Nov. 01, 2014		Aug. 02, 2014		3-May-14		Feb. 01, 2014		Nov. 02, 2013		Aug. 03, 2013		4-May-13	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013
Quarterly Financial Information [Line Items]
Net revenue	$857,452	[1]	$930,136	[2]	$961,545	[3]	$957,830	[4]	$931,749	[5]	$931,226	[6]	$807,056	[7]	$734,369	$3,706,963	$3,404,400	$3,168,630
Gross profit	440,321	[1]	475,162	[2]	483,804	[3]	463,970	[4]	454,497	[5]	466,245	[6]	420,997	[7]	398,931
Net income	$81,693	[1]	$115,304	[2]	$138,870	[3]	$99,479	[4]	$97,129	[5]	$103,156	[6]	$61,826	[7]	$53,209	$435,346	$315,320	$306,585
Net income per share:
Basic	$0.16	[1]	$0.22	[2]	$0.27	[3]	$0.20	[4]	$0.20	[5]	$0.21	[6]	$0.13	[7]	$0.11	$0.85	$0.64	$0.55
Diluted	$0.16	[1]	$0.22	[2]	$0.27	[3]	$0.19	[4]	$0.19	[5]	$0.21	[6]	$0.12	[7]	$0.11	$0.84	$0.63	$0.54
[1]	The fourth quarter of fiscal 2015 includes $3.4 million of restructuring and other exit-related cost, and $2.8 million of costs associated with the surety bond to appeal the CMU judgment.
[2]	The third quarter of fiscal 2015 includes $2.3 million of costs associated with the surety bond to appeal the CMU judgment.
[3]	The second quarter of fiscal 2015 includes an $8.8 million gain from the sale of an investment and $2.2 million of costs associated with the surety bond to appeal the CMU judgment.
[4]	The first quarter of fiscal 2015 includes $8.5 million of restructuring and other exit-related cost that includes a $3.4 million write off of IPR&D.
[5]	The fourth quarter of fiscal 2014 includes $9.5 million for anticipated litigation settlements that do not relate to the litigation with CMU, $8.1 million charge for the impairment of an intangible asset and a $7.0 million gain from the sale of a business.
[6]	The third quarter of fiscal 2014 includes $4.2 million of restructuring and other exit-related costs.
[7]	The second quarter of fiscal 2014 includes $5.2 million for litigation settlements that do not relate to the litigation with CMU.

Quarterly_Unaudited_Consolidat1

Quarterly Unaudited Consolidated Statements of Operations Data (Parenthetical) (Detail) (USD $)	3 Months Ended							12 Months Ended
	Jan. 31, 2015	Nov. 01, 2014	Aug. 02, 2014	3-May-14	Feb. 01, 2014	Nov. 02, 2013	Aug. 03, 2013	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013
Quarterly Financial Information [Line Items]
Restructuring charges			$8,800,000	$8,500,000		$4,200,000		$13,824,000	$4,732,000	$1,257,000
Write off of IPR&D				3,400,000				3,400,000		800,000
Costs associated with the surety bond to appeal the Carnegie Mellon University judgment	2,800,000	2,300,000	2,200,000
Litigation settlements	3,400,000				9,500,000		5,200,000
Gain from sale of business					7,000,000
Impairment charge, intangible asset					$8,100,000				$8,100,000

Recovered_Sheet2

SCHEDULE II - VALUATION AND QUALIFYING ACCOUNTS (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Jan. 31, 2015	Feb. 01, 2014	Feb. 02, 2013
Allowance for doubtful accounts and sales return reserve
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	$2,294	$7,921	$2,663
Additions	3,041	3,808	9,024
Deductions	-3,223	-9,435	-3,766
Balance at End of Year	2,112	2,294	7,921
Deferred tax valuation
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	335,890	299,449	259,316
Additions	46,906	36,441	40,133
Balance at End of Year	$382,796	$335,890	$299,449