Microchip Technology (MCHP) 10-K 24 May 16 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Mar. 31, 2016	May. 16, 2016	Sep. 30, 2015
Document And Entity Information [Abstract]
Entity Registrant Name	MICROCHIP TECHNOLOGY INC
Entity Central Index Key	827,054
Current Fiscal Year End Date	--03-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Mar. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		214,815,223
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 8,528,992,176

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2016	Mar. 31, 2015
ASSETS
Cash and cash equivalents	$ 2,092,751	$ 607,815
Short-term investments	353,284	1,351,054
Accounts receivable, net	290,183	273,937
Inventories	306,815	279,456
Prepaid expenses	41,992	34,717
Deferred tax assets		71,045
Assets held for sale	0	13,989
Other current assets	11,688	32,604
Total current assets	3,096,713	2,664,617
Property, plant and equipment, net	609,396	581,572
Long-term investments	118,549	383,326
Goodwill	1,012,652	571,271
Intangible assets, net	606,349	504,417
Long-term deferred tax assets	14,831
Long-term deferred tax assets		0
Other assets	109,025	75,510
Total assets	5,567,515	4,780,713
LIABILITIES AND EQUITY
Accounts payable	79,312	86,866
Accrued liabilities	119,265	100,978
Deferred income on shipments to distributors	183,432	166,128
Total current liabilities	382,009	353,972
Senior convertible debentures	1,234,733	1,174,036
Junior convertible debentures	196,304	190,870
Long-term line of credit	1,052,000	461,952
Long-term income tax payable	111,061	114,336
Long-term deferred tax liability	399,218
Long-term deferred tax liability		381,192
Other long-term liabilities	41,271	43,329
Stockholders' equity:
Preferred stock, $0.001 par value; authorized 5,000,000 shares; no shares issued or outstanding	0	0
Common stock, $0.001 par value; authorized 450,000,000 shares; 227,416,789 shares issued and 204,081,727 shares outstanding at March 31, 2016; 218,789,994 shares issued and 202,080,306 shares outstanding at March 31, 2015	204	202
Additional paid-in capital	1,391,553	999,515
Common stock held in treasury: 23,335,062 shares at March 31, 2016; 16,709,688 shares at March 31, 2015	(820,066)	(515,679)
Accumulated other comprehensive (loss) income	(3,357)	11,076
Retained earnings	1,582,585	1,549,540
Microchip Technology stockholders' equity	2,150,919	2,044,654
Noncontrolling interests	0	16,372
Total equity	2,150,919	2,061,026
Total liabilities and equity	$ 5,567,515	$ 4,780,713

CONSOLIDATED BALANCE SHEETS CON

CONSOLIDATED BALANCE SHEETS CONSOLIDATED BALANCE SHEETS (PARENTHETICAL) - $ / shares	Mar. 31, 2016	Mar. 31, 2015
Statement of Financial Position [Abstract]
Common Stock, Par or Stated Value Per Share	$ 0.001	$ 0.001
Common Stock, Shares Authorized	450,000,000	450,000,000
Common Stock, Shares, Issued	227,416,789	218,789,994
Common Stock, Shares, Outstanding	204,081,727	202,080,306
Preferred Stock, Par or Stated Value Per Share	$ 0.001	$ 0.001
Preferred Stock, Shares Authorized	5,000,000	5,000,000
Preferred Stock, Shares Issued	0	0
Preferred Stock, Shares Outstanding	0	0
Treasury Stock, Shares	23,335,062	16,709,688

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Income Statement
Net sales		$ 2,173,334	$ 2,147,036	$ 1,931,217
Cost of sales (1)	[1]	967,870	917,472	802,474
Gross profit		1,205,464	1,229,564	1,128,743
Operating expenses:
Research and development (1)	[1]	372,596	349,543	305,043
Selling, general and administrative (1)	[1]	301,670	274,815	267,278
Amortization of acquired intangible assets		174,896	176,746	94,534
Special charges, net		3,957	2,840	3,024
Operating expenses		853,119	803,944	669,879
Operating income		352,345	425,620	458,864
Losses on equity method investments		(345)	(317)	(177)
Other income (expense):
Interest income		24,447	19,527	16,485
Interest expense		(104,018)	(62,034)	(48,716)
Loss on retirement of convertible debentures		0	(50,631)	0
Other income, net		8,864	13,742	5,898
Income before income taxes		281,293	345,907	432,354
Income tax (benefit) provision		(42,632)	(19,418)	37,073
Net income		323,925	365,325	395,281
Less: Net loss attributable to noncontrolling interests		207	3,684	0
Net income attributable to Microchip Technology		$ 324,132	$ 369,009	$ 395,281
Basic net income per common share attributable to Microchip Technology stockholders		$ 1.59	$ 1.84	$ 1.99
Diluted net income per common share attributable to Microchip Technology stockholders		1.49	1.65	1.82
Dividends declared per common share		$ 1.433	$ 1.425	$ 1.417
Basic common shares outstanding		203,384	200,937	198,291
Diluted common shares outstanding		217,388	223,561	217,630
[1]	Includes share-based compensation expense as follows:Cost of sales 8,252 9,010 7,340Research and development 32,022 28,164 24,554Selling, general and administrative 31,146 21,422 21,893

CONSOLIDATED STATEMENTS OF INC5

CONSOLIDATED STATEMENTS OF INCOME CONSOLIDATED STATEMENTS OF INCOME (PARENTHETICAL) - USD ($) $ in Thousands		12 Months Ended
		Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated share based compensation expense		$ 71,420	$ 58,596	$ 53,787
Cost of sales
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated share based compensation expense	[1]	8,252	9,010	7,340
Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated share based compensation expense		32,022	28,164	24,554
Selling General And Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Allocated share based compensation expense		$ 31,146	$ 21,422	$ 21,893
[1]	During the year ended March 31, 2016, $7.9 million of share-based compensation expense was capitalized to inventory, and $8.3 million of previously capitalized share-based compensation expense in inventory was sold. During the year ended March 31, 2015, $6.8 million of share-based compensation expense was capitalized to inventory, and $9.0 million of previously capitalized share-based compensation expense in inventory was sold. During the year ended March 31, 2014, $7.4 million of share-based compensation expense was capitalized to inventory, and $7.3 million of previously capitalized share-based compensation expense in inventory was sold.

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Net income	$ 323,925	$ 365,325	$ 395,281
Less: Net loss attributable to noncontrolling interests	207	3,684	0
Net income attributable to Microchip Technology	324,132	369,009	395,281
Unrealized holding (losses) gains, net of tax effect of $0, $12 and $497, respectively	(3,241)	33,759	(4,377)
Reclassification of realized transactions, net of tax effect of $0, $12 and $776, respectively	(10,948)	(18,694)	(1,595)
Change in minimum pension liability, net of tax effect of $18, ($76) and $55, respectively	31	(127)	88
Change in net foreign currency translation adjustment	0	(5,188)	0
Other comprehensive (loss) income, net of taxes	(14,158)	9,750	(5,884)
Less: Other comprehensive loss attributable to noncontrolling interests	0	866	0
Other comprehensive (loss) income attributable to Microchip Technology	(14,158)	10,616	(5,884)
Comprehensive income	309,767	375,075	389,397
Less: Comprehensive loss attributable to noncontrolling interests	207	4,550	0
Comprehensive income attributable to Microchip Technology	$ 309,974	$ 379,625	$ 389,397

CONSOLIDATED STATEMENTS OF COM7

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (PARENTHETICAL) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Other Comprehensive Income (Loss), Available-for-sale Securities, Tax, Portion Attributable to Parent	$ 0	$ 12	$ 497
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized (Gain) Loss Arising During Period, Tax	$ 18	$ (76)	$ 55

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Cash flows from operating activities:
Net income	$ 323,925	$ 365,325	$ 395,281
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	283,171	278,298	189,139
Deferred income taxes	(60,425)	(32,811)	5,321
Share-based compensation expense related to equity incentive plans	71,420	58,596	53,787
Excess tax benefit from share-based compensation	(758)	(1,216)	(1,411)
Loss on retirement of junior convertible debentures	0	50,631	0
Amortization of debt discount on convertible debentures	48,022	14,791	8,970
Amortization of debt issuance costs	3,968	2,463	1,959
Losses on equity method investments	345	317	177
(Gains) losses on sale of assets	(960)	0	244
Loss on write-down of fixed assets	0	362	0
Impairment of intangible assets	629	1,881	350
Realized gain on available-for-sale investments	(13,727)	(18,469)	0
Realized gain on equity method investment	(2,225)	0	0
Impairment of available-for-sale investment	3,995	0	0
Amortization of premium on available-for-sale investments	9,044	9,949	10,754
Special (income) charges	(819)	0	(459)
Gain on shares of acquired company	0	0	(2,438)
Changes in operating assets and liabilities, excluding impact of acquisitions:
Increase in accounts receivable	(2,150)	(15,893)	(12,508)
Decrease (increase) in inventories	48,245	25,517	(18,500)
Increase (Decrease) in Deferred Income	16,962	18,330	8,846
Decrease in accounts payable and accrued liabilities	(20,836)	(33,992)	(11,633)
Change in other assets and liabilities	36,657	(2,897)	48,685
Net cash provided by operating activities	744,483	721,182	676,564
Cash flows from investing activities:
Purchases of available-for-sale investments	(1,573,867)	(959,318)	(1,337,482)
Sales and maturities of available-for-sale investments	2,824,231	1,097,065	951,296
Sale of equity method investment	2,667	0	0
Acquisition of Micrel, net of cash acquired	(343,928)	0	0
Acquisition of ISSC, net of cash acquired	0	(252,469)	0
Purchase of additional controlling interest in ISSC	(18,051)	(32,095)	0
Acquisition of Supertex, net of cash acquired	0	(375,365)	0
Other business acquisitions, net of cash acquired	0	0	(11,187)
Investments in other assets	(7,056)	(6,663)	(9,069)
Proceeds from sale of assets	14,296	0	16,235
Capital expenditures	(97,895)	(149,472)	(113,072)
Net cash provided by (used in) investing activities	800,397	(678,317)	(503,279)
Cash flows from financing activities:
Payments to retire junior convertible debentures	0	(1,134,621)	0
Proceeds from issuance of senior convertible debentures	0	1,725,000	0
Repayments of revolving loan under previous credit facility	0	0	(650,000)
Repayments of revolving loan under new credit facility	(1,614,452)	(1,697,642)	(453,500)
Proceeds from borrowings on revolving loan under previous credit facility	0	0	30,000
Proceeds from borrowings on revolving loan under new credit facility	2,204,500	1,859,594	753,500
Proceeds from issuance of long-term borrowings	0	0	350,000
Repayments of long-term borrowings	0	(350,000)	0
Deferred financing costs	(2,156)	(32,846)	(7,515)
Payment of cash dividends	(291,087)	(286,478)	(281,204)
Repurchase of common stock	(363,829)	0	0
Proceeds from sale of common stock	28,718	34,433	60,086
Tax payments related to shares withheld for vested restricted stock units	(21,720)	(19,504)	(22,640)
Contingent consideration payment	0	0	(14,700)
Capital lease payments	(676)	(604)	(454)
Excess tax benefit from share-based compensation	758	1,216	1,411
Net cash (used in) provided by financing activities	(59,944)	98,548	(235,016)
Effect of foreign exchange rate changes on cash and cash equivalents	0	(201)	0
Net increase (decrease) in cash and cash equivalents	1,484,936	141,212	(61,731)
Cash and cash equivalents at beginning of period	607,815	466,603	528,334
Cash and cash equivalents at end of period	$ 2,092,751	$ 607,815	$ 466,603

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Thousands	Total	Senior Subordinated Convertible Debenture Due 2025 [Member]	Junior Subordinated Convertible Debentures Due2037 Member	Supertex Inc. [Member]	Common Stock and Additional Paid-in Capital	Common Stock and Additional Paid-in CapitalSupertex Inc. [Member]	Common Stock and Additional Paid-in CapitalMicrel Incorporated [Member]	Common Stock Held in Treasury	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Parent [Member]	Parent [Member]Senior Subordinated Convertible Debenture Due 2025 [Member]	Parent [Member]Junior Subordinated Convertible Debentures Due2037 Member	Parent [Member]Supertex Inc. [Member]	Noncontrolling Interest [Member]
Balance at Mar. 31, 2013	$ 1,933,470				$ 1,255,823			$ (682,220)	$ 6,935	$ 1,352,932	$ 1,933,470				$ 0
Balance, common stock shares issued (in shares) at Mar. 31, 2013					218,790,000
Balance, common stock held in treasury (in shares) at Mar. 31, 2013								22,317,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	395,281									395,281	395,281
Other comprehensive income (loss)	(5,884)								(5,884)		(5,884)
Proceeds from sales of common stock through employee equity incentive plans (shares)					4,161,000
Proceeds from sales of common stock through employee equity incentive plans (amount)	60,086				$ 60,086						60,086
Restricted stock unit and stock appreciation right withholdings (shares)					(631,000)
Restricted stock unit and stock appreciation right withholdings (amount)	(22,640)				$ (22,640)						(22,640)
Treasury stock used for new issuances (shares)					(3,530,000)			(3,530,000)
Treasury stock used for new issuances (amount)					$ (104,838)			$ 104,838
Tax benefit (shortfall) from equity incentive plans	1,411				1,411						1,411
Share-based compensation	54,941				54,941						54,941
Cash dividend	(281,204)									(281,204)	(281,204)
Balance at Mar. 31, 2014	2,135,461				$ 1,244,783			$ (577,382)	1,051	1,467,009	2,135,461				0
Balance, common stock shares issued (in shares) at Mar. 31, 2014					218,790,000
Balance, common stock held in treasury (in shares) at Mar. 31, 2014								18,787,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Additions due to acquisition of controlling interest in ISSC	52,467														52,467
Net income	365,325									369,009	369,009				(3,684)
Other comprehensive income (loss)	9,750								10,616		10,616				(866)
Other	240														240
Purchase of additional interests	(32,095)				$ 345				(591)		(246)				(31,849)
Proceeds from sales of common stock through employee equity incentive plans (shares)					2,503,000
Proceeds from sales of common stock through employee equity incentive plans (amount)	34,433				$ 34,369						34,369				64
Restricted stock unit and stock appreciation right withholdings (shares)					(426,000)
Restricted stock unit and stock appreciation right withholdings (amount)	(19,504)				$ (19,504)						(19,504)
Treasury stock used for new issuances (shares)					(2,077,000)			(2,077,000)
Treasury stock used for new issuances (amount)					$ (61,703)			$ 61,703
Tax benefit (shortfall) from equity incentive plans	1,220				1,220						1,220
Share-based compensation	56,687				56,687						56,687
Non-cash consideration, exchange of employee stock awards (amount)				$ 1,622		$ 1,622								$ 1,622
Convertible Debt - retirement of 2037 debentures			$ (606,926)		(606,926)								$ (606,926)
Convertible Debt - issuance of 2025 debentures		$ 348,824			348,824							$ 348,824
Cash dividend	(286,478)									(286,478)	(286,478)
Balance at Mar. 31, 2015	$ 2,061,026				$ 999,717			$ (515,679)	11,076	1,549,540	2,044,654				16,372
Balance, common stock shares issued (in shares) at Mar. 31, 2015	218,789,994				218,790,000
Balance, common stock held in treasury (in shares) at Mar. 31, 2015	16,709,688							16,710,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 323,925									324,132	324,132				(207)
Other comprehensive income (loss)	(14,158)								(14,158)		(14,158)				0
Purchase of additional interests	(18,051)				$ (1,611)				(275)		(1,886)				(16,165)
Proceeds from sales of common stock through employee equity incentive plans (shares)					2,491,000
Proceeds from sales of common stock through employee equity incentive plans (amount)	28,718				$ 28,718						28,718				0
Restricted stock unit and stock appreciation right withholdings (shares)					(489,000)
Restricted stock unit and stock appreciation right withholdings (amount)	(21,720)				$ (21,720)						(21,720)
Treasury stock used for new issuances (shares)					(2,002,000)			(2,002,000)
Treasury stock used for new issuances (amount)					$ (59,442)			$ 59,442
Tax benefit (shortfall) from equity incentive plans	(567)				(567)						(567)
Share-based compensation	73,556				73,556						73,556
Issuance of common stock - acquisitions (shares)							8,627,000
Issuance of common stock - acquisitions (amount)	369,054						$ 369,054				369,054
Non-cash consideration, exchange of employee stock awards (amount)	$ 4,052						$ 4,052				4,052
Purchase of treasury stock (shares)	8,600,000							8,627,000
Purchase of treasury stock (amount)	$ (363,829)							$ (363,829)			(363,829)
Cash dividend	(291,087)									(291,087)	(291,087)
Balance at Mar. 31, 2016	$ 2,150,919				$ 1,391,757			$ (820,066)	$ (3,357)	$ 1,582,585	$ 2,150,919				$ 0
Balance, common stock shares issued (in shares) at Mar. 31, 2016	227,416,789				227,417,000
Balance, common stock held in treasury (in shares) at Mar. 31, 2016	23,335,062							23,335,000

Significant Accounting Policies

Significant Accounting Policies (Notes)	12 Months Ended
	Mar. 31, 2016
Accounting Policies [Abstract]
Summary of significant accounting policies	SIGNIFICANT ACCOUNTING POLICIES Nature of Business Microchip develops, manufactures and sells specialized semiconductor products used by its customers for a wide variety of embedded control applications. Microchip's product portfolio comprises general purpose and specialized 8-bit, 16-bit, and 32-bit microcontrollers, a broad spectrum of high-performance linear, mixed-signal, power management, thermal management, RF, timing, safety, security, wired connectivity and wireless connectivity devices, as well as serial EEPROMs, Serial Flash memories, Parallel Flash memories and serial SRAM memories. Microchip also licenses Flash-IP solutions that are incorporated in a broad range of products. Principles of Consolidation The consolidated financial statements include the accounts of Microchip Technology Incorporated and its majority-owned subsidiaries (Microchip or the Company). The Company owned 100% of the outstanding stock in all of its subsidiaries as of March 31, 2016 . As further discussed in Note 2, the Company did not hold 100% of the outstanding common stock of ISSC Technologies Corporation (ISSC) for a period through June 30, 2015. The noncontrolling interest in the Company's net income from ISSC has been excluded from net income attributable to the Company in the Company's consolidated statements of income. All of the Company's subsidiaries are included in the consolidated financial statements. All significant intercompany accounts and transactions have been eliminated in consolidation. Revenue Recognition The Company recognizes revenue when the earnings process is complete, as evidenced by an agreement with the customer, transfer of title as well as fixed or determinable pricing and when collectability is reasonably assured. The Company recognizes revenue from product sales to original equipment manufacturers (OEMs) upon shipment and records reserves for estimated customer returns. Distributors worldwide generally have broad price protection and product return rights, so the Company defers revenue recognition until the distributor sells the product to their customer. Revenue is recognized when the distributor sells the product to their end customer, at which time the sales price becomes fixed or determinable. Revenue is not recognized upon the Company's shipment to the distributors since, due to discounts from list price as well as price protection rights, the sales price is not substantially fixed or determinable at that time. At the time of shipment to these distributors, the Company records a trade receivable for the selling price as there is a legally enforceable right to payment, relieves inventory for the carrying value of goods shipped since legal title has passed to the distributor, and records the gross margin in deferred income on shipments to distributors on its consolidated balance sheets. Deferred income on shipments to distributors effectively represents gross margin on the sale to the distributor at the initial shipment date; however, the amount of gross margin recognized by the Company in future periods will be less than the deferred margin as a result of credits granted to distributors on specifically identified products and customers to allow the distributors to earn a competitive gross margin on the sale of the Company's products to their end customers and price protection concessions related to market pricing conditions. The Company sells the majority of the items in its product catalog to its distributors worldwide at a uniform list price. However, distributors resell the Company's products to end customers at a very broad range of individually negotiated price points. The majority of the Company's distributors' resales require a reduction from the original list price paid. Often, under these circumstances, the Company remits back to the distributor a portion of their original purchase price after the resale transaction is completed in the form of a credit against the distributors' outstanding accounts receivable balance. The credits are on a per unit basis and are not given to the distributor until they provide information regarding the sale to their end customer. The price reductions vary significantly based on the customer, product, quantity ordered, geographic location and other factors and discounts to a price less than the Company's cost have historically been rare. The effect of granting these credits establishes the net selling price from the Company to its distributors for the product and results in the net revenue recognized by the Company when the product is sold by the distributors to their end customers. Thus, a portion of the "deferred income on shipments to distributors" balance represents the amount of distributors' original purchase price that will be credited back to the distributor in the future. The wide range and variability of negotiated price concessions granted to distributors does not allow the Company to accurately estimate the portion of the balance in the deferred income on shipments to distributors account that will be credited back to the distributors. Therefore, the Company does not reduce deferred income on shipments to distributors or accounts receivable by anticipated future price concessions; rather, price concessions are recorded against deferred income on shipments to distributors when incurred, which is generally at the time the distributor sells the product. At March 31, 2016 , the Company had approximately $ 267.2 million of deferred revenue and $ 83.8 million in deferred cost of sales recognized as $ 183.4 million of deferred income on shipments to distributors. At March 31, 2015 , the Company had approximately $ 260.9 million of deferred revenue and $ 94.8 million in deferred cost of sales recognized as $ 166.1 million of deferred income on shipments to distributors. The deferred income on shipments to distributors that will ultimately be recognized in the Company's income statement will be lower than the amount reflected on the balance sheet due to price credits to be granted to the distributors when the product is sold to their customers. These price credits historically have resulted in the deferred income approximating the overall gross margins that the Company recognizes in the distribution channel of its business. The Company reduces product pricing through price protection based on market conditions, competitive considerations and other factors. Price protection is granted to distributors on the inventory they have on hand at the date the price protection is offered. When the Company reduces the price of its products, it allows the distributor to claim a credit against its outstanding accounts receivable balances based on the new price of the inventory it has on hand as of the date of the price reduction. There is no immediate revenue impact from the price protection, as it is reflected as a reduction of the deferred income on shipments to distributors' balance. Products returned by distributors and subsequently scrapped have historically been immaterial to the Company's consolidated results of operations. The Company routinely evaluates the risk of impairment of the deferred cost of sales component of the deferred income on shipments to distributors' account. Because of the historically immaterial amounts of inventory that have been scrapped, and historically rare instances where discounts given to a distributor result in a price less than the Company's cost, the Company believes the deferred costs have a low risk of material impairment. Shipping charges billed to customers are included in net sales, and the related shipping costs are included in cost of sales. The Company collects and remits certain sales-related taxes on sales of inventory and reports such amounts under the net method in its consolidated statements of income. For licenses or other technology arrangements without an upgrade period, non-royalty revenue from the license is recognized upon delivery of the technology if the fee is fixed or determinable and collection of the fee is reasonably assured. Royalties are recognized when reported to the Company, which generally coincides with the receipt of payment. In certain limited circumstances, the Company enters into license and other arrangements for technologies that the Company is continuing to enhance and refine or under which it is obligated to provide unspecified enhancements. Under these arrangements, non-royalty revenue is recognized over the lesser of (1) the estimated period that the Company has historically enhanced and developed refinements to the specific technology, typically one to three years (the "upgrade period"), and (2) the remaining portion of the upgrade period after the date of delivery of all specified technology and documentation, provided that the fee is fixed or determinable and collection of the fee is reasonably assured. Royalties received during the upgrade period are recognized as revenue based on an amortization calculation of the elapsed portion of the upgrade period compared to the entire estimated upgrade period. Royalties received after the upgrade period has elapsed are recognized when reported to the Company, which generally coincides with the receipt of payment. Product Warranty The Company typically warrants its products against defects in materials and workmanship and non-conformance to specifications for 12 to 24 months. The majority of the Company's product warranty claims are settled through the return of the defective product and the shipment of replacement product. Warranty returns are included within the Company's allowance for returns, which is based on historical return rates. Actual future returns could differ from the allowance established. In addition, the Company accrues a liability for specific warranty costs expected to be settled other than through product return and replacement, if a loss is probable and can be reasonably estimated. Product warranty expenses during fiscal 2016 , 2015 , and 2014 were immaterial. Advertising Costs The Company expenses all advertising costs as incurred. Advertising costs were immaterial for the fiscal years ended March 31, 2016 , 2015 and 2014 . Research and Development Research and development costs are expensed as incurred. Assets purchased to support the Company's ongoing research and development activities are capitalized when related to products which have achieved technological feasibility or that have alternative future uses and are amortized over their estimated useful lives. Research and development expenses include expenditures for labor, share-based payments, depreciation, masks, prototype wafers, and expenses for development of process technologies, new packages, and software to support new products and design environments. Foreign Currency Translation The Company's foreign subsidiaries are considered to be extensions of the U.S. company and any translation gains and losses related to these subsidiaries are included in other income (expense) in the consolidated statements of income. As the U.S. dollar is utilized as the functional currency, gains and losses resulting from foreign currency transactions (transactions denominated in a currency other than the subsidiaries' functional currency) are also included in income. For a portion of fiscal 2015, certain foreign subsidiaries acquired as part of the Company's acquisition activities had the local currency as the functional currency. Once these entities were integrated into the Company's legal structure and intercompany agreements were executed, the U.S. dollar became the functional currency for such entities. Income Taxes The Company provides for income taxes in accordance with principles contained in ASC Topic 740, Income Taxes. Under these principles, the Company recognizes the amount of income tax payable or refundable for the current year and deferred tax assets and liabilities for the future tax consequences of events that have been recognized in its consolidated financial statements or tax returns. Deferred tax assets and liabilities are measured using enacted tax rates in effect for the year in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in earnings in the period when the new rate is enacted. Deferred tax assets are evaluated for future realization and reduced by a valuation allowance if it is more likely than not that a portion will not be realized. In assessing whether it is more likely than not that deferred tax assets will be realized, the Company considers all available evidence, both positive and negative, including its recent cumulative earnings experience and expectations of future available taxable income of the appropriate character by taxing jurisdiction, tax attribute carry back and carry forward periods available to them for tax reporting purposes, and prudent and feasible tax planning strategies. The Company measures and recognizes the amount of tax benefit that should be recorded for financial statement purposes for uncertain tax positions taken or expected to be taken in a tax return. With respect to uncertain tax positions, the Company evaluates the recognized tax benefits for de-recognition, classification, interest and penalties, interim period accounting and disclosure requirements. Judgment is required in assessing the future tax consequences of events that have been recognized in its consolidated financial statements or tax returns. Cash and Cash Equivalents All highly liquid investments, including marketable securities purchased with a remaining maturity of three months or less when acquired are considered to be cash equivalents. Available-for-Sale Investments The Company classifies its investments in debt and marketable equity securities as available-for-sale based upon management's intent with regard to the investments and the nature of the underlying securities. The Company's available-for-sale investments consist of government agency bonds, municipal bonds, auction rate securities (ARS), corporate bonds and marketable equity securities. The Company's investments are carried at fair value with unrealized gains and losses reported in stockholders' equity unless losses are considered to be other than temporary impairments in which case the losses are recognized through the statement of income. Premiums and discounts are amortized or accreted over the life of the related available-for-sale security. Dividend and interest income are recognized when earned. The cost of available-for-sale debt securities sold is calculated using the first-in, first-out (FIFO) basis at the individual security level for sales from multiple lots. For sales of marketable equity securities, the Company uses an average cost basis at the individual security level. The Company includes within short-term investments its income yielding available-for-sale securities that can be readily converted to cash and includes within long-term investments those income yielding available-for-sale securities with maturities of over one year that have unrealized losses attributable to them or those that cannot be readily liquidated. Except as discussed in Note 4, the Company intends and has the ability to hold its long-term investments with temporary impairments until such time as these assets are no longer impaired. Such recovery of unrealized losses is not expected to occur within the next year. Derivative Instruments Derivative instruments are required to be recorded at fair value as either assets or liabilities in the Company's consolidated balance sheet. The Company's accounting policies for derivative instruments depends on whether the instrument has been designated and qualifies as part of a hedging relationship and further, on the type of hedging relationship. The Company does not apply hedge accounting to foreign currency forward contracts. Gains and losses associated with currency rate changes on forward contracts are recorded currently in income. These gains and losses have been immaterial to the Company's financial statements. Interest rate derivative instruments designated as fair value hedges are designed to manage the exposure to interest rate movements and to reduce borrowing costs by converting fixed-rate debt into floating-rate debt. Under these agreements, the Company agrees to exchange, at specified intervals, the difference between the fixed and floating interest amounts calculated by reference to an agreed-upon notional principal amount. For derivative instruments that are designated and qualify as fair value hedges, the gain or loss on the derivatives as well as the offsetting gain or loss on the hedged item attributable to the hedged risk are recognized in earnings. The Company evaluates hedge effectiveness at inception and on an ongoing basis. If a derivative is no longer expected to be highly effective, hedge accounting is discontinued. In February 2016, the Company terminated its interest rate derivative instruments. Allowance for Doubtful Accounts The Company maintains an allowance for doubtful accounts for estimated losses resulting from the inability of its customers to make required payments, which is included in bad debt expense. The Company determines the adequacy of this allowance by regularly reviewing the composition of its accounts receivable aging and evaluating individual customer receivables, considering such customer's financial condition, credit history and current economic conditions. Inventories Inventories are valued at the lower of cost or market using the first-in, first-out method. The Company writes down its inventory for estimated obsolescence or unmarketable inventory in an amount equal to the difference between the cost of inventory and the estimated market value based upon assumptions about future demand and market conditions. If actual market conditions are less favorable than those projected by the Company, additional inventory write-downs may be required. Inventory impairment charges establish a new cost basis for inventory and charges are not subsequently reversed to income even if circumstances later suggest that increased carrying amounts are recoverable. In estimating reserves for obsolescence, the Company primarily evaluates estimates of demand over a 12-month period and provides reserves for inventory on hand in excess of the estimated 12-month demand. Estimates for projected 12-month demand are generally based on the average shipments of the prior three-month period, which are then annualized to adjust for any potential seasonality in the Company's business. The estimated 12-month demand is compared to the Company's most recently developed sales forecast to further reconcile the 12-month demand estimate. Management reviews and adjusts the estimates as appropriate based on specific situations. For example, demand can be adjusted up for new products for which historic sales are not representative of future demand. Alternatively, demand can be adjusted down to the extent any existing products are being replaced or discontinued. In periods where the Company's production levels are substantially below normal operating capacity, unabsorbed overhead production costs associated with the reduced production levels of the Company's manufacturing facilities are charged directly to cost of sales. Property, Plant and Equipment Property, plant and equipment are stated at cost. Major renewals and improvements are capitalized, while maintenance and repairs are expensed when incurred. The Company's property and equipment accounting policies incorporate estimates, assumptions and judgments relative to the useful lives of its property and equipment. Depreciation is provided for assets placed in service on a straight-line basis over the estimated useful lives of the relative assets, which range from 10 to 40 years for buildings and building improvements and 3 to 7 years for machinery and equipment. The Company evaluates the carrying value of its property and equipment when events or changes in circumstances indicate that the carrying value of such assets may be impaired. Asset impairment evaluations are, by nature, highly subjective. Senior and Junior Subordinated Convertible Debentures The Company separately accounts for the liability and equity components of its senior and junior subordinated convertible debentures in a manner that reflects its nonconvertible debt (unsecured debt) borrowing rate when interest cost is recognized. This results in a bifurcation of a component of the debt, classification of that component in equity and the accretion of the resulting discount on the debt to be recognized as part of interest expense in its consolidated statements of income. Lastly, the Company includes the dilutive effect of the shares of its common stock issuable upon conversion of the outstanding senior and junior subordinated convertible debentures in its diluted income per share calculation regardless of whether the market price triggers or other contingent conversion features have been met. The Company applies the treasury stock method as it has the intent and ability to settle the principal amounts of the senior and junior subordinated convertible debentures in cash. This method results in incremental dilutive shares when the average market value of the Company's common stock for a reporting period exceeds the conversion prices per share which were $66.05 and $24.31 for the senior and junior subordinated convertible debentures, respectively, at March 31, 2016 and adjust as dividends are recorded in the future. Upon a de-recognition event, the Company estimates the fair value of the liability component and compares that to the carrying amount in order to calculate the appropriate amount of gain or loss. The remaining amounts paid or issued (in the case of non cash consideration in the form of shares of common stock) are recognized as a reduction of additional paid-in-capital. The fair value of the liability component is estimated using the current comparable borrowing rate for an otherwise identical non-convertible debt instrument. Litigation The Company's estimated range of liability related to pending litigation is based on claims that management believes a loss is probable and for which an amount or range of loss is estimable. In the event that a probable loss cannot be reasonably estimated, the Company does not accrue for such losses. Management makes a determination as to when a potential loss is reasonably possible based on relevant accounting literature and then includes appropriate disclosure of the contingency. As the Company continues to monitor litigation matters, whether deemed material as of March 31, 2016 or not, its determination could change, and the Company may decide, at some future date, to establish an appropriate reserve. Business Combinations All of the Company's business combinations are accounted for at fair value under the acquisition method of accounting. Under the acquisition method of accounting, (i) acquisition-related costs, except for those costs incurred to issue debt or equity securities, will be expensed in the period incurred; (ii) non-controlling interests will be valued at fair value at the acquisition date; (iii) in-process research and development will be recorded at fair value as an intangible asset at the acquisition date and amortized once the technology reaches technological feasibility; (iv) restructuring costs associated with a business combination will be expensed subsequent to the acquisition date; and (v) changes in deferred tax asset valuation allowances and income tax uncertainties after the acquisition date will be recognized through income tax expense or directly in contributed capital. The measurement of fair value of assets acquired and liabilities assumed requires significant judgment. The valuation of intangible assets and acquired investments, in particular, requires that the Company use valuation techniques such as the income approach. The income approach includes the use of a discounted cash flow model, which includes discounted cash flow scenarios and requires the following significant estimates: revenue, expenses, capital spending and other costs, and discount rates based on the respective risks of the cash flows. The valuation of non-marketable equity investments acquired also takes into account variables such as conditions reflected in the capital markets, recent financing activity by the investees, the investees' capital structure and the terms of the investees' issued interests. Goodwill and Other Intangible Assets Goodwill is recorded when the purchase price paid for an acquisition exceeds the estimated fair value of the net identified tangible and intangible assets acquired. The Company is required to perform an impairment review annually, and more frequently under certain circumstances. The goodwill is subjected to this annual impairment test during the fourth quarter of the Company's fiscal year. The Company engages primarily in the development, manufacture and sale of semiconductor products as well as technology licensing. As a result, the Company concluded there are two reporting units, semiconductor products and technology licensing. Under the qualitative goodwill impairment assessment standard, management evaluates whether it is more likely than not that goodwill is impaired. If it is determined that it is more likely than not, the Company proceeds with the next step of the impairment test, which compares the fair value of the reporting unit to its carrying value. If the Company determines through the impairment process that goodwill has been impaired, the Company will record the impairment charge in its results of operation. Through March 31, 2016 , the Company has not had impaired goodwill. The Company's other intangible assets represent existing technologies, core and developed technology, in-process research and development, trademarks and trade names, and customer-related intangibles. Other intangible assets are amortized over their respective estimated lives, ranging from one year to ten years. In the event that facts and circumstances indicate intangibles or other long-lived assets may be impaired, the Company evaluates the recoverability and estimated useful lives of such assets. In-process research and development is capitalized until such time the related projects are completed or abandoned at which time the capitalized amounts will begin to be amortized or written off. Impairment of Long-Lived Assets The Company assesses whether indicators of impairment of long-lived assets are present. If such indicators are present, the Company determines whether the sum of the estimated undiscounted cash flows attributable to the assets in question is less than their carrying value. If less, the Company recognizes an impairment loss based on the excess of the carrying amount of the assets over their respective fair values. Fair value is determined by discounted future cash flows, appraisals or other methods. If the assets determined to be impaired are to be held and used, the Company recognizes an impairment loss through a charge to operating results to the extent the present value of anticipated net cash flows attributable to the asset are less than the asset's carrying value. The Company would depreciate the remaining value over the remaining estimated useful life of the asset. Share-Based Compensation The Company has equity incentive plans under which non-qualified stock options and restricted stock units (RSUs) have been granted to employees and non-employee members of the Board of Directors. In the second half of fiscal 2006, the Company adopted RSUs as its primary equity incentive compensation instrument for employees. The Company also has employee stock purchase plans for eligible employees. The Company estimates the fair value of share-based payment awards on the date of grant using an option pricing model. The value of the portion of the award that is ultimately expected to vest is recognized as expense straight-line over the requisite service periods. The Company has estimated the fair value of each award as of the date of grant using the Black-Scholes option pricing model, which was developed for use in estimating the value of traded options that have no vesting restrictions and that are freely transferable. Determining the appropriate fair-value model and calculating the fair value of share-based awards at the date of grant requires judgment. The fair value of RSUs is based on the fair market value of the Company's common stock on the date of grant discounted for expected future dividends. The Company uses the Black-Scholes option pricing model to estimate the fair value of employee stock options and rights to purchase shares under stock purchase plans. Option pricing models, including the Black-Scholes model, also require the use of input assumptions, including expected volatility, expected life, expected dividend rate, and expected risk-free rate of return. The Company uses a blend of historical and implied volatility based on options freely traded in the open market as it believes this is more reflective of market conditions and a better indicator of expected volatility than using purely historical volatility. The expected life of the awards is based on historical and other economic data trended into the future. The risk-free interest rate assumption is based on observed interest rates appropriate for the expected terms of the Company's awards. The dividend yield assumption is based on the Company's history and expectation of future dividend payouts. The Company estimates the number of share-based awards which will be forfeited due to employee turnover. Quarterly changes in the estimated forfeiture rate would affect share-based compensation, as the impact on prior period amortization for all unvested awards is recognized in the period the forfeiture estimate is changed. If the actual forfeiture rate is higher than the estimated forfeiture rate, then an adjustment is made to increase the estimated forfeiture rate, which will result in a decrease to the expense recognized in the financial statements. If the actual forfeiture rate is lower than the estimated forfeiture rate, then an adjustment is made to decrease the estimated forfeiture rate, which will result in an increase to the expense recognized in the financial statements. If forfeiture adjustments are made, they would affect the Company's results of operations. The effect of forfeiture adjustments in the years ended March 31, 2016 , 2015 and 2014 was immaterial. The Company evaluates the assumptions used to value its awards on a quarterly basis. If factors change and the Company employs different assumptions, share-based compensation expense may differ significantly from what was recorded in the past. If there are any modifications or cancellations of the underlying unvested securities, the Company may be required to accelerate or increase any remaining unearned share-based compensation expense. Future share-based compensation expense and unearned share-based compensation will increase to the extent that the Company grants additional equity awards to employees or it assumes unvested equity awards in connection with acquisitions. Concentrations of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of investments in debt securities and trade receivables. Investments in debt securities with original maturities of greater than six months consist primarily of AAA and AA rated financial instruments and counterparties. The Company's investments are primarily in direct obligations of the U.S. government or its agencies, corporate bonds, and municipal bonds. Concentrations of credit risk with respect to accounts receivable are generally not significant due to the diversity of the Company's customers and geographic sales areas. The Company sells its products primarily to OEMs and distributors in the Americas, Europe and Asia. The Company performs ongoing credit evaluations of its customers' financial condition and, as deemed necessary, may require collateral, primarily letters of credit. Distributor advances, included in deferred income on shipments to distributors in the consolidated balance sheets, totaled $ 102.9 million at March 31, 2016 and $ 116.0 million at March 31, 2015 . On sales to distributors, the Company's payment terms generally require the distributor to settle amounts owed to the Company for an amount in excess of their ultimate cost. T

Business Acquisitions (Notes)

Business Acquisitions (Notes)	12 Months Ended
	Mar. 31, 2016
Business Combinations [Abstract]
Business acquisitions	BUSINESS ACQUISITIONS Acquisition of Micrel On August 3, 2015, the Company acquired Micrel, a publicly traded company based in San Jose, California. The Company paid an aggregate of approximately $ 430.0 million in cash and issued an aggregate of 8,626,795 shares of its common stock to Micrel shareholders. The number of shares issued in the transaction was subsequently repurchased in the open market during the year ended March 31, 2016. The total consideration transferred in the acquisition, including approximately $ 4.1 million of non cash consideration for the exchange of certain share-based payment awards of Micrel for stock awards of the Company, and approximately $ 13.1 million of cash consideration for the payout of vested employee stock awards, was approximately $ 816.2 million . The Company financed the cash portion of the purchase price using borrowings under its existing credit agreement. As a result of the acquisition, Micrel became a wholly owned subsidiary of the Company. Micrel's business is to design, develop, manufacture and market a range of high-performance analog, power and mixed-signal integrated circuits. Micrel's products address a wide range of end markets including industrial and automotive, wireline communications, enterprise and cloud infrastructure and mobility. Micrel also manufactures custom analog and mixed-signal circuits and provides wafer foundry services for customers which produce electronic systems utilizing semiconductor manufacturing processes as well as micro-electrical mechanical system technologies. The Company's primary reason for this acquisition was to expand the Company's range of solutions, products and capabilities by extending its served available market. The acquisition was accounted for under the acquisition method of accounting, with the Company identified as the acquirer, and the operating results of Micrel have been included in the Company's consolidated financial statements as of the closing date of the acquisition. Under the acquisition method of accounting, the aggregate amount of consideration paid by the Company was allocated to Micrel's net tangible assets and intangible assets based on their estimated fair values as of August 3, 2015. The excess of the purchase price over the value of the net tangible assets and intangible assets was recorded to goodwill. The factors contributing to the recognition of goodwill were based upon the Company's conclusion that there are strategic and synergistic benefits that are expected to be realized from the acquisition. The goodwill has been allocated to the Company's semiconductor products reporting segment. None of the goodwill related to the Micrel acquisition is deductible for tax purposes. The Company retained an independent third-party appraiser to assist management in its valuation; however, the purchase price allocation has not been finalized. This could result in adjustments to the fair values of the assets acquired and liabilities assumed, the useful lives of intangible assets, the residual amount allocated to goodwill and deferred income taxes recognized. The preliminary allocation of the purchase price is based on the best estimates of management and is subject to revision based on the final valuations and estimates of useful lives. The table below represents the preliminary allocation of the purchase price, including adjustments to the purchase price allocation from the originally reported figures at September 30, 2015, to the net assets acquired based on their estimated fair values as of August 3, 2015, as well as the associated estimated useful lives of the acquired intangible assets at that date (amounts in thousands): Assets acquired Previously Reported September 30, 2015 Adjustments March 31, 2016 Cash and cash equivalents $ 99,196 $ — $ 99,196 Accounts receivable, net 12,296 1,800 14,096 Inventories 78,967 (5,499 ) 73,468 Prepaid expenses and other current assets 10,548 104 10,652 Property, plant and equipment, net 38,566 — 38,566 Goodwill 437,060 3,932 440,992 Purchased intangible assets 274,800 (1,300 ) 273,500 Other assets 4,268 — 4,268 Total assets acquired 955,701 (963 ) 954,738 Liabilities assumed Accounts payable (11,068 ) — (11,068 ) Other current liabilities (30,241 ) (1,400 ) (31,641 ) Deferred tax liabilities (88,796 ) 761 (88,035 ) Long-term income tax payable (9,239 ) 1,602 (7,637 ) Other long-term liabilities (127 ) — (127 ) Total liabilities assumed (139,471 ) 963 (138,508 ) Purchase price allocated $ 816,230 $ — $ 816,230 Purchased Intangible Assets Useful Life August 3, 2015 (in years) (in thousands) Core/developed technology 10 $ 175,800 In-process technology 10 21,000 Customer-related 5 71,100 Backlog 1 5,600 Total purchased intangible assets $ 273,500 Purchased intangible assets include core and developed technology, in-process research and development, customer-related intangibles and acquisition-date backlog. The estimated fair values of the core and developed technology and in-process research and development were determined based on the present value of the expected cash flows to be generated by the respective existing technology or future technology. The core and developed technology intangible assets are being amortized commensurate with the expected cash flows used in the initial determination of fair value. In-process technology is capitalized until such time as the related projects are completed or abandoned at which time the capitalized amounts will begin to be amortized or written off. Customer-related intangible assets consist of Micrel's contractual relationships and customer loyalty related to its distributor and end-customer relationships, and the fair values of the customer-related intangibles were determined based on Micrel's projected revenues. An analysis of expected attrition and revenue growth for existing customers was prepared from Micrel's historical customer information. Customer relationships are being amortized in a manner consistent with the estimated cash flows associated with the existing customers and anticipated retention rates. Backlog relates to the value of orders not yet shipped by Micrel at the acquisition date, and the preliminary fair values were based on the estimated profit associated with those orders. Backlog related assets are being recognized commensurate with recognition of the revenue for the orders on which the backlog intangible assets were determined. Amortization expense associated with acquired intangible assets is not deductible for tax purposes. Thus, approximately $ 99.7 million was established as a net deferred tax liability for the future amortization of the intangible assets offset by $ 11.4 million of net deferred tax assets. The amount of Micrel net sales included in the Company's consolidated statements of income for the year ended March 31, 2016 was approximately $ 116.4 million . The operations of Micrel were fully integrated into the Company's operations as of November 1, 2015 and as such, cost of sales and operating expenses were no longer segregated as of that date. The following unaudited pro-forma consolidated results of operations for the years ended March 31, 2016 and 2015 assume the Micrel acquisition occurred as of April 1, 2014. The pro-forma adjustments are mainly comprised of acquired inventory fair value costs and amortization of purchased intangible assets. The pro-forma results of operations are presented for informational purposes only and are not indicative of the results of operations that would have been achieved if the acquisition had taken place on April 1, 2014 or of results that may occur in the future (amounts in thousands except per share data): Year ended March 31, 2016 2015 Net sales $ 2,283,517 $ 2,352,727 Net income $ 365,654 $ 278,673 Basic earnings per share $ 1.80 $ 1.39 Diluted earnings per share $ 1.68 $ 1.25 Acquisition of ISSC On July 17, 2014, the Company acquired an 83.5% interest in Taiwan-based ISSC, a leading provider of low power Bluetooth and advanced wireless solutions for the Internet of Things (IoT) market. The Company acquired the 83.5% ownership interest through a tender offer process. After the completion of the tender offer, the Company continued to acquire additional shares of ISSC, and as of June 30, 2015, the Company had completed the acquisition of 100% of the outstanding shares of ISSC. The acquisition was accounted for under the acquisition method of accounting. The table below represents the allocation of the purchase price to the net assets acquired based on their estimated fair values as of July 17, 2014 as well as the associated estimated useful lives of the acquired intangible assets at that date. The purchase price allocation was finalized as of June 30, 2015 (amounts in thousands): Assets acquired June 30, 2015 Cash and cash equivalents $ 15,120 Short-term investments 27,063 Accounts receivable, net 8,792 Inventories 16,542 Prepaid expenses and other current assets 2,501 Property, plant and equipment, net 2,637 Goodwill 154,788 Purchased intangible assets (1) 147,800 Other assets 1,370 Total assets acquired 376,613 Liabilities assumed Accounts payable (9,860 ) Other current liabilities (16,535 ) Long-term income tax payable (4,791 ) Deferred tax liability (25,126 ) Other long-term liabilities (245 ) Total liabilities assumed (56,557 ) Net assets acquired including noncontrolling interest 320,056 Less: noncontrolling interest (52,467 ) Net assets acquired $ 267,589 (1) Purchased Intangible Assets Useful Life July 17, 2014 (in years) (in thousands) Core/developed technology 10 $ 68,900 In-process technology 10 27,200 Customer-related 3 51,100 Backlog 1 600 $ 147,800 Acquisition of Supertex On April 1, 2014, the Company acquired Supertex Inc., a publicly traded company based in Sunnyvale, California. Supertex is a leader in high voltage analog and mixed signal technologies, with a strong position in the medical, lighting and industrial control markets. The acquisition was accounted for under the acquisition method of accounting. The table below represents the allocation of the purchase price to the net assets acquired based on their estimated fair values as of April 1, 2014 as well as the associated estimated useful lives of the acquired intangible assets at that date. The purchase price allocation was finalized on March 31, 2015 (amounts in thousands): Assets acquired March 31, 2015 Cash and cash equivalents $ 14,790 Short-term investments 140,984 Accounts receivable, net 7,047 Inventories 27,630 Prepaid expenses 1,493 Deferred tax assets 2,456 Other current assets 12,625 Property, plant and equipment, net 15,679 Goodwill 143,160 Purchased intangible assets (1) 89,600 Other assets 325 Total assets acquired 455,789 Liabilities assumed Accounts payable (8,481 ) Accrued liabilities (19,224 ) Long-term income tax payable (3,796 ) Deferred tax liability (32,511 ) Total liabilities assumed (64,012 ) Net assets acquired $ 391,777 (1) Purchased Intangible Assets Useful Life April 1, 2014 (in years) (in thousands) Core/developed technology 10 $ 68,900 In-process technology 10 1,900 Customer-related 2 17,700 Backlog 1 1,100 $ 89,600

Special Charges (Notes)

Special Charges (Notes)	12 Months Ended
	Mar. 31, 2016
Other Nonrecurring (Income) Expense [Abstract]
Special charges	SPECIAL CHARGES During fiscal 2016, the Company incurred special charges of $ 4.0 million comprised of $ 11.2 million related to severance, office closing and other costs associated with the Company's acquisition activity and legal settlement costs of approximately $ 4.3 million partially offset by special income of $ 11.5 million related to an insurance settlement for reimbursement of funds Microchip previously paid to settle a lawsuit in the second quarter of fiscal 2013. During fiscal 2015 and fiscal 2014, the Company incurred special charges of $ 2.8 million and $3.0 million , respectively, related to severance, office closing and other costs associated with its acquisition activity.

Investments (Notes)

Investments (Notes)	12 Months Ended
	Mar. 31, 2016
Investments [Abstract]
Investments	INVESTMENTS The Company's investments are intended to establish a high-quality portfolio that preserves principal, meets liquidity needs, avoids inappropriate concentrations, and delivers an appropriate yield in relationship to the Company's investment guidelines and market conditions. The following is a summary of available-for-sale securities at March 31, 2016 (amounts in thousands): Available-for-sale Securities Adjusted Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Government agency bonds $ 468,290 $ 439 $ (99 ) $ 468,630 Corporate bonds and debt 1,000 — — 1,000 Marketable equity securities 2,195 8 — 2,203 Total $ 471,485 $ 447 $ (99 ) $ 471,833 The following is a summary of available-for-sale securities at March 31, 2015 (amounts in thousands): Available-for-sale Securities Adjusted Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Government agency bonds $ 741,780 $ 676 $ (200 ) $ 742,256 Municipal bonds 41,552 155 (9 ) 41,698 Auction rate securities 9,825 — — 9,825 Time deposits (1) 506 — — 506 Corporate bonds and debt 924,818 2,376 (265 ) 926,929 Marketable equity securities 1,362 11,804 — 13,166 Total $ 1,719,843 $ 15,011 $ (474 ) $ 1,734,380 (1) Time deposits in various financial institutions with maturities greater than three months that will mature within one year. At March 31, 2016 , the Company's available-for-sale debt securities and marketable equity securities are presented on the consolidated balance sheets as short-term investments of $ 353.3 million and long-term investments of $ 118.5 million . At March 31, 2015 , the Company’s available-for-sale debt securities and marketable equity securities are presented on the consolidated balance sheets as short-term investments of $ 1,351.1 million and long-term investments of $ 383.3 million . The Company sold available-for-sale investments for proceeds of $ 1,501.5 million , $ 273.9 million and $ 135.3 million during the years ended March 31, 2016 , 2015 and 2014 , respectively. The Company sold available-for-sale investments during the fourth quarter of fiscal 2016 to finance a portion of the purchase price of its Atmel acquisition which closed on April 4, 2016. The Company had net realized gains of $13.7 million and $ 18.5 million from sales of available-for-sale marketable equity and debt securities during the years ended March 31, 2016 and 2015 , respectively. The Company had no material realized gains or losses from the sale of available-for-sale equity and debt securities during the year ended March 31, 2014 . The Company determines the cost of available-for-sale debt securities sold on a FIFO basis at the individual security level for sales from multiple lots. For sales of marketable equity securities, the Company uses an average cost basis at the individual security level. Gains and losses recognized in earnings are credited or charged to other income (expense) on the consolidated statements of income. At March 31, 2016 , the Company's marketable equity securities consisted of an investment in Adesto Technologies Corporation, which effected its initial public offering on the NASDAQ stock exchange on October 26, 2015. This investment was previously classified as available-for-sale corporate debt as of March 31, 2015. At March 31, 2015 , the Company's marketable equity securities consisted of an investment in Hua Hong Semiconductor Limited (Hua Hong), which effected its initial public offering on the Hong Kong stock exchange on October 15, 2014. The Company sold all of its remaining shares of Hua Hong in the three months ended June 30, 2015. The following tables show all investments in an unrealized loss position for which an other-than-temporary impairment has not been recognized and the related gross unrealized losses and fair value, aggregated by investment category and length of time that the individual securities have been in a continuous unrealized loss position (amounts in thousands): March 31, 2016 Less than 12 Months 12 Months or Greater Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss Government agency bonds $ 148,562 $ (99 ) $ — $ — $ 148,562 $ (99 ) Corporate bonds and debt — — 1,000 — 1,000 — Total $ 148,562 $ (99 ) $ 1,000 $ — $ 149,562 $ (99 ) March 31, 2015 Less than 12 Months 12 Months or Greater Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss Government agency bonds $ 162,948 $ (142 ) $ 29,942 $ (58 ) $ 192,890 $ (200 ) Municipal bonds 13,318 (9 ) — — 13,318 (9 ) Corporate bonds and debt 163,095 (219 ) 19,021 (46 ) 182,116 (265 ) Total $ 339,361 $ (370 ) $ 48,963 $ (104 ) $ 388,324 $ (474 ) Management does not believe any of the unrealized losses represent an other-than-temporary impairment based on its evaluation of available evidence as of March 31, 2016 and the Company's intent is to hold these investments until these assets are no longer impaired. For those debt securities not scheduled to mature until after March 31, 2017, such recovery is not anticipated to occur in the next year and these investments have been classified as long-term investments on the consolidated balance sheet. The amortized cost and estimated fair value of the available-for-sale securities at March 31, 2016 , by contractual maturity, excluding marketable equity securities of $2.2 million , which have no contractual maturity, are shown below (amounts in thousands). Expected maturities can differ from contractual maturities because the issuers of the securities may have the right to prepay obligations without prepayment penalties, and the Company views its available-for-sale securities as available for current operations. Adjusted Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Available-for-sale Due in one year or less $ 41,078 $ 5 $ (5 ) $ 41,078 Due after one year and through five years 428,212 434 (94 ) 428,552 Due after five years and through ten years — — — — Due after ten years — — — — Total $ 469,290 $ 439 $ (99 ) $ 469,630 The amortized cost and estimated fair value of the available-for-sale securities at March 31, 2015 , by maturity, excluding marketable equity securities of $ 13.2 million and corporate debt of $ 6.2 million , which have no contractual maturity, are shown below (amounts in thousands). Adjusted Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Available-for-sale Due in one year or less $ 224,531 $ 512 $ (34 ) $ 225,009 Due after one year and through five years 1,395,685 2,648 (330 ) 1,398,003 Due after five years and through ten years 82,250 47 (110 ) 82,187 Due after ten years 9,825 — — 9,825 Total $ 1,712,291 $ 3,207 $ (474 ) $ 1,715,024

Fair Value Measurements (Notes)

Fair Value Measurements (Notes)	12 Months Ended
	Mar. 31, 2016
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS Accounting rules for fair value clarify that fair value is an exit price, representing the amount that would be received to sell 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 liability. As a basis for considering such assumptions, the Company utilizes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows: Level 1- Observable inputs such as quoted prices in active markets; Level 2- Inputs, other than the quoted prices in active markets, that are observable either directly or indirectly; and Level 3- Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions. Marketable Debt Instruments Marketable debt instruments include instruments such as corporate bonds and debt, government agency bonds, bank deposits, municipal bonds, and money market mutual funds. When the Company uses observable market prices for identical securities that are traded in less active markets, the Company classifies its marketable debt instruments as Level 2. When observable market prices for identical securities are not available, the Company prices its marketable debt instruments using non-binding market consensus prices that are corroborated with observable market data; quoted market prices for similar instruments; or pricing models, such as a discounted cash flow model, with all significant inputs derived from or corroborated with observable market data. Non-binding market consensus prices are based on the proprietary valuation models of pricing providers or brokers. These valuation models incorporate a number of inputs, including non-binding and binding broker quotes; observable market prices for identical or similar securities; and the internal assumptions of pricing providers or brokers that use observable market inputs and, to a lesser degree, unobservable market inputs. The Company corroborates non-binding market consensus prices with observable market data using statistical models when observable market data exists. The discounted cash flow model uses observable market inputs, such as LIBOR-based yield curves, currency spot and forward rates, and credit ratings. Derivatives The Company's derivative assets include interest rate swaps that are classified as Level 2 as the Company uses inputs other than quoted prices that are observable for the assets. The Level 2 derivative assets are primarily valued using standard calculations and models that use readily observable market data as their basis. Assets Measured at Fair Value on a Recurring Basis Assets measured at fair value on a recurring basis at March 31, 2016 are as follows (amounts in thousands): Quoted Prices in Active Markets for Identical Instruments (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Balance Assets Cash and cash equivalents: Money market mutual funds $ 1,787,446 $ — $ — $ 1,787,446 Deposit accounts — 305,305 — 305,305 Short-term investments: Marketable equity securities 2,203 — — 2,203 Corporate bonds and debt — 1,000 — 1,000 Government agency bonds — 350,081 — 350,081 Long-term investments: Government agency bonds — 118,549 — 118,549 Total assets measured at fair value $ 1,789,649 $ 774,935 $ — $ 2,564,584 Assets measured at fair value on a recurring basis at March 31, 2015 are as follows (amounts in thousands): Quoted Prices in Active Markets for Identical Instruments (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Balance Assets Cash and cash equivalents: Money market mutual funds $ 279,833 $ — $ — $ 279,833 Deposit accounts — 327,982 — 327,982 Short-term investments: Marketable equity securities 13,166 — — 13,166 Corporate bonds and debt — 756,664 — 756,664 Time deposits (1) — 506 — 506 Government agency bonds — 549,737 — 549,737 Municipal bonds — 30,981 — 30,981 Long-term investments: Corporate bonds and debt — 164,075 6,190 170,265 Government agency bonds — 192,519 — 192,519 Municipal bonds — 10,717 — 10,717 Auction rate securities — — 9,825 9,825 Other assets Derivative assets — 8,928 — 8,928 Total assets measured at fair value $ 292,999 $ 2,042,109 $ 16,015 $ 2,351,123 (1) Time deposits in various financial institutions with maturities greater than three months that will mature within one year. There were no transfers between Level 1 and Level 2 during fiscal 2016 or fiscal 2015. The following table presents a reconciliation for all assets measured at fair value on a recurring basis, excluding accrued interest components, using significant unobservable inputs (Level 3) for the year ended March 31, 2016 . There were no changes in the fair value of these assets measured on a recurring basis during fiscal 2015 (amounts in thousands): Year ended March 31, 2016 Auction Rate Securities Corporate Debt Total Gains (Losses) Balance at March 31, 2015 $ 9,825 $ 6,190 $ — Total gains (losses) (realized): Included in earnings 2,780 (3,995 ) (1,215 ) Purchases, sales, issuances, and settlements, net (12,605 ) — — Transfers out of Level 3 — (2,195 ) — Balance at March 31, 2016 $ — $ — $ (1,215 ) Transfers into or out of Level 3 are made if the inputs used in the financial models measuring the fair values of the assets became unobservable or observable, respectively, in the current marketplace. During the year ended March 31, 2016 , the Company transferred $2.2 million of corporate debt assets out of Level 3 as the inputs used to value these assets became observable in the current marketplace and are classified as Level 1 as of March 31, 2016 . This transfer was effective on October 26, 2015. During the fourth quarter of fiscal 2016, the Company sold its ARS for proceeds of $12.6 million. At March 31, 2015 , the Company's ARS for which auctions were unsuccessful were made up of securities related to the insurance industry valued at $ 9.8 million with a par value of $ 22.4 million . During the period the Company held the ARS, the Company estimated the fair value of its ARS, which were classified as Level 3 securities, based on the following: (i) the underlying structure of each security; (ii) the present value of future principal and interest payments discounted at rates considered to reflect current market conditions; (iii) consideration of the probabilities of default, auction failure, or repurchase at par for each period; and (iv) estimates of the recovery rates in the event of default for each security. The significant unobservable inputs used in the fair value measurement of the ARS were estimated risk free discount rates, liquidity risk premium, and the liquidity horizon. The risk free discount rate applied to these securities was 2.0% to 2.5% adjusted for the liquidity risk premium which ranged from 9.1% to 29.5% . The anticipated liquidity horizon ranged from 7 to 10 years. Gains and losses recognized in earnings are credited or charged to other income (expense) on the consolidated statements of income. Assets Measured and Recorded at Fair Value on a Non-Recurring Basis The Company's non-marketable equity, cost method investments, and non-financial assets, such as intangible assets, assets held for sale and property, plant and equipment, are recorded at fair value on a non-recurring basis. These assets are subject to fair value adjustments in certain circumstances, for example, when there is evidence of impairment. The Company's non-marketable and cost method investments are monitored on a quarterly basis for impairment charges. The fair values of these investments have been determined as Level 3 fair value measurements because the valuations use unobservable inputs that require management's judgment due to the absence of quoted market prices. There were no impairment charges recognized on these investments during the years ended March 31, 2016 or March 31, 2015 . During the year ended March 31, 2014 , the Company recognized impairment charges of $0.7 million on these investments. These investments are included in other assets on the consolidated balance sheets. The fair value measurements related to the Company's non-financial assets, such as intangible assets, assets held for sale and property, plant and equipment are based on available market prices at the measurement date based on transactions of similar assets and third-party independent appraisals, less costs to sell where appropriate. The Company classifies these measurements as Level 2.

Fair Value of Financial Instrum

Fair Value of Financial Instruments (Notes)	12 Months Ended
	Mar. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	FAIR VALUE OF FINANCIAL INSTRUMENTS The carrying amount of cash equivalents approximates fair value because their maturity is less than three months. Management believes the carrying amount of the equity and cost-method investments materially approximated fair value at March 31, 2016 based upon unobservable inputs. The fair values of these investments have been determined as Level 3 fair value measurements. The fair values of the Company's line of credit borrowings are estimated using discounted cash flow analyses, based on the Company's current incremental borrowing rates for similar types of borrowing arrangements and approximate carrying value. Based on the borrowing rates currently available to the Company for bank loans with similar terms and average maturities, the fair value of the Company's line of credit borrowings at March 31, 2016 approximated book value and are considered Level 2 in the fair value hierarchy described in Note 5. The carrying amount of accounts receivable, accounts payable and accrued liabilities approximates fair value due to the short-term maturity of the amounts and are considered Level 2 in the fair value hierarchy. Fair Value of Subordinated Convertible Debentures The Company measures the fair value of its senior and junior subordinated convertible debentures for disclosure purposes. These fair values are based on observable market prices for these debentures, which are traded in less active markets and are therefore classified as a Level 2 fair value measurement, and exclude the impacts of derivative activity. The carrying amounts and fair values of the Company’s senior and junior subordinated convertible debentures as of March 31, 2016 and 2015 are as follows (amounts in thousands): March 31, 2016 March 31, 2015 Carrying Amount Fair Value Carrying Amount Fair Value 1.625% Senior Subordinated Convertible Debentures $ 1,234,733 $ 1,762,088 $ 1,174,036 $ 1,787,531 2.125% Junior Subordinated Convertible Debentures $ 196,304 $ 1,143,117 $ 190,870 $ 1,124,125

Accounts Receivable (Notes)

Accounts Receivable (Notes)	12 Months Ended
	Mar. 31, 2016
Accounts Receivable, Net [Abstract]
Accounts Receivable	ACCOUNTS RECEIVABLE Accounts receivable consists of the following (amounts in thousands): March 31, 2016 March 31, 2015 Trade accounts receivable $ 289,013 $ 269,844 Other 3,710 6,714 Total accounts receivable, gross 292,723 276,558 Less allowance for doubtful accounts 2,540 2,621 Total accounts receivable, net $ 290,183 $ 273,937

Inventories (Notes)

Inventories (Notes)	12 Months Ended
	Mar. 31, 2016
Inventory Disclosure [Abstract]
Inventories	INVENTORIES The components of inventories consist of the following (amounts in thousands): March 31, 2016 March 31, 2015 Raw materials $ 12,179 $ 13,263 Work in process 208,283 197,565 Finished goods 86,353 68,628 Total inventories $ 306,815 $ 279,456 Inventories are valued at the lower of cost or market using the first-in, first-out method. Inventory impairment charges establish a new cost basis for inventory and charges are not subsequently reversed to income even if circumstances later suggest that increased carrying amounts are recoverable.

Assets Held for Sale (Notes)

Assets Held for Sale (Notes)	12 Months Ended
	Mar. 31, 2016
Property, Plant and Equipment Assets Held-for-sale Disclosure [Abstract]
Assets Held for Sale	ASSETS HELD FOR SALE During the year ended March 31, 2015, the Company began to actively market real property it acquired in the Supertex acquisition. As of March 31, 2015, the Company classified the property as held for sale on its consolidated balance sheet at its fair value of approximately $ 14.0 million . The Company sold the property on July 22, 2015 for $ 14.3 million .

Property, Plant and Equipment (

Property, Plant and Equipment (Notes)	12 Months Ended
	Mar. 31, 2016
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment Disclosure [Text Block]	PROPERTY, PLANT AND EQUIPMENT Property, plant and equipment consists of the following (amounts in thousands): March 31, 2016 March 31, 2015 Land $ 63,907 $ 55,624 Building and building improvements 458,379 434,403 Machinery and equipment 1,645,617 1,576,074 Projects in process 99,370 76,315 Total property, plant and equipment, gross 2,267,273 2,142,416 Less accumulated depreciation and amortization 1,657,877 1,560,844 Total property, plant and equipment, net $ 609,396 $ 581,572 Depreciation expense attributed to property, plant and equipment was $ 103.9 million , $ 97.3 million and $ 89.7 million for the fiscal years ending March 31, 2016 , 2015 and 2014 , respectively.

Noncontrolling interests (Notes

Noncontrolling interests (Notes)	12 Months Ended
	Mar. 31, 2016
Noncontrolling Interest [Abstract]
Noncontrolling Interest Disclosure [Text Block]	NONCONTROLLING INTERESTS The following table presents the changes in the components of noncontrolling interests for the years ended March 31, 2016 and March 31, 2015 (amounts in thousands): Noncontrolling Interests Balance at March 31, 2014 $ — Additions due to acquisition of controlling interest in ISSC 52,467 Net loss attributable to noncontrolling interests (3,684 ) Other comprehensive loss attributable to noncontrolling interests (866 ) Purchase of additional interests (31,849 ) Other 304 Balance at March 31, 2015 16,372 Net loss attributable to noncontrolling interests (207 ) Purchase of additional interests (16,165 ) Balance at March 31, 2016 $ — The following table presents the effect of changes in the Company's ownership interest in ISSC on the Company's stockholders' equity (amounts in thousands): Year ended March 31, 2016 2015 Net income attributable to Microchip Technology stockholders $ 324,132 $ 369,009 (Decrease) increase in paid-in capital for purchase of additional interests (1,611 ) 345 Increase in paid-in capital for converted stock options — 1,094 Net transfers (to) from noncontrolling interest (1,611 ) 1,439 Change from net income attributable to Microchip Technology stockholders and transfers (to) from noncontrolling interest $ 322,521 $ 370,448 The Company acquired the remaining noncontrolling interest in ISSC during the first quarter of fiscal 2016.

Intangible Assets and Goodwill

Intangible Assets and Goodwill (Notes)	12 Months Ended
	Mar. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets and Goodwill	INTANGIBLE ASSETS AND GOODWILL Intangible assets consist of the following (amounts in thousands): March 31, 2016 Gross Amount Accumulated Amortization Net Amount Core and developed technology $ 724,883 $ (255,460 ) $ 469,423 Customer-related 278,542 (200,331 ) 78,211 Trademarks and trade names 11,700 (7,571 ) 4,129 In-process technology 54,308 — 54,308 Distribution rights 5,580 (5,302 ) 278 Total $ 1,075,013 $ (468,664 ) $ 606,349 March 31, 2015 Gross Amount Accumulated Amortization Net Amount Core and developed technology $ 549,415 $ (189,149 ) $ 360,266 Customer-related 262,769 (192,283 ) 70,486 Trademarks and trade names 13,180 (6,979 ) 6,201 In-process technology 67,142 — 67,142 Distribution rights 5,580 (5,258 ) 322 Total $ 898,086 $ (393,669 ) $ 504,417 The Company amortizes intangible assets over their expected useful lives, which range between 1 and 15 years. During the year ended March 31, 2016 , as a result of the acquisition of Micrel, the Company acquired $ 175.8 million of core and developed technology which has a weighted average amortization period of 10 years, $ 71.1 million of customer-related intangible assets which have a weighted average amortization period of 5 years, $ 5.6 million of intangible assets related to backlog with an amortization period of 1 year and $ 21.0 million of in-process technology which has a weighted average amortization period of 10 years and will begin amortization once the technology reaches technological feasibility. In fiscal 2016 , $ 33.8 million of in-process technology reached technological feasibility and was reclassified as core and developed technology and began being amortized over its estimated useful life. The following is an expected amortization schedule for the intangible assets for fiscal 2017 through fiscal 2021 , absent any future acquisitions or impairment charges (amounts in thousands): Year ending March 31, Projected Amortization Expense 2017 $137,321 2018 110,811 2019 94,573 2020 76,683 2021 50,974 Amortization expense attributed to intangible assets was $ 179.3 million , $ 181.0 million and $ 99.4 million for fiscal years 2016 , 2015 and 2014 , respectively. In fiscal 2016 , $ 3.6 million was charged to cost of sales and $ 175.7 million was charged to operating expenses. In fiscal 2015 , $ 3.8 million was charged to cost of sales and $ 177.2 million was charged to operating expenses. In fiscal 2014 , $ 4.7 million was charged to cost of sales and $ 94.7 million was charged to operating expenses. The Company recognized impairment charges of $ 0.6 million , $ 1.9 million and $ 0.4 million in fiscal years 2016 , 2015 and 2014 , respectively. Goodwill activity for fiscal years 2016 and 2015 was as follows (amounts in thousands): Semiconductor Products Reporting Unit Technology Licensing Reporting Unit Balance at March 31, 2014 $ 256,897 $ 19,200 Additions due to the acquisition of Supertex 143,160 — Additions due to acquisition of controlling interest in ISSC 154,399 — Adjustments due to other acquisitions 624 — Foreign currency translation adjustments (3,009 ) — Balance at March 31, 2015 552,071 19,200 Additions due to the acquisition of Micrel 440,992 — Adjustments due to the acquisition of ISSC 389 — Balance at March 31, 2016 $ 993,452 $ 19,200 At March 31, 2016 , the Company applied a qualitative goodwill impairment screen to its two reporting units, concluding it was not more likely than not that goodwill was impaired. Through March 31, 2016 , the Company has never recorded an impairment charge against its goodwill balance.

Income taxes (Notes)

Income taxes (Notes)	12 Months Ended
	Mar. 31, 2016
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES The income tax provision consists of the following (amounts in thousands): Year Ended March 31, 2016 2015 2014 Pretax Income: U.S. $ (75,515 ) $ (944 ) $ 28,245 Foreign 356,808 346,851 404,109 $ 281,293 $ 345,907 $ 432,354 Current expense (benefit): U.S. Federal $ (3,966 ) $ (3,185 ) $ 992 State (188 ) (24 ) 64 Foreign 21,947 16,602 30,697 Total current $ 17,793 $ 13,393 $ 31,753 Deferred expense (benefit): U.S. Federal $ (42,207 ) $ (22,641 ) $ 14,445 State (1,990 ) (1,562 ) 929 Foreign (16,228 ) (8,608 ) (10,054 ) Total deferred (60,425 ) (32,811 ) 5,320 Total $ (42,632 ) $ (19,418 ) $ 37,073 The tax benefit associated with the Company's equity incentive plans reduced taxes currently payable by $ 0.8 million , $ 1.2 million and $ 1.4 million for the years ended March 31, 2016 , 2015 and 2014 , respectively. These amounts were credited to additional paid-in capital in each of these fiscal years. The provision for income taxes differs from the amount computed by applying the statutory federal tax rate to income before income taxes. The sources and tax effects of the differences in the total income tax provision are as follows (amounts in thousands): Year Ended March 31, 2016 2015 2014 Computed expected income tax provision $ 98,453 $ 121,067 $ 151,324 State income taxes, net of federal benefits (1,246 ) (20 ) 686 Research and development tax credits - current year (13,542 ) (9,703 ) (4,875 ) Research and development tax credits - prior years (2,511 ) (1,789 ) 1,600 Foreign income taxed at lower than the federal rate (114,497 ) (106,939 ) (116,003 ) Increases related to current and prior year tax positions 14,462 19,769 16,809 Decreases related to prior year tax positions (1) (12,103 ) (33,100 ) (14,581 ) Withholding taxes 5,970 5,218 6,212 Change in valuation allowance (2,482 ) (14,286 ) — Intercompany prepaid tax asset amortization (15,493 ) (1,089 ) — Other 357 1,454 (4,099 ) Total $ (42,632 ) $ (19,418 ) $ 37,073 (1) The release of prior year tax positions during fiscal 2016 increased each of the basic and diluted net income per common share by $0.06 . The release of prior year tax positions during fiscal 2015 increased the basic and diluted net income per common share by $0.16 and $0.15 , respectively. The release of prior year tax positions during fiscal 2014 increased each of the basic and diluted net income per common share by $0.07 . The foreign tax rate differential benefit primarily relates to the Company's operations in Thailand, Cayman and Ireland. The Company's Thailand manufacturing operations are currently subject to numerous tax holidays granted to the Company based on its investment in property, plant and equipment in Thailand. The Company's tax holiday periods in Thailand expire at various times in the future, however, the Company actively seeks to obtain new tax holidays. The Company does not expect the future expiration of any of its tax holiday periods in Thailand to have a material impact on its effective tax rate. The aggregate dollar benefits derived from these tax holidays approximated $ 6.0 million , $ 12.4 million and $ 16.8 million in fiscal 2016 , 2015 and 2014 , respectively. No U.S. income taxes have been provided on substantially all of the filing basis undistributed foreign earnings and profits of approximately $ 3.4 billion as of March 31, 2016 since the Company has the ability and intent to permanently reinvest these amounts. If such earnings were repatriated, additional tax expense may result, although the calculation of such additional taxes is not practicable. During the year ended March 31, 2016, the Company effectively settled several open tax positions related to the examination of fiscal years 2012 and 2011 by the U.S. Internal Revenue Service (IRS). In addition, the Company benefited from the expiration of the statute of limitations and other releases related to previously accrued tax reserves. The total tax benefit associated with these items resulted in a reduction of income tax provision of approximately $ 12.1 million and a decrease in the effective tax rate of 4.3% in fiscal 2016. The tax effects of temporary differences that give rise to significant portions of the Company's deferred tax assets and deferred tax liabilities are as follows (amounts in thousands): March 31, 2016 2015 Deferred tax assets: Deferred intercompany profit $ 12,642 $ 10,865 Deferred income on shipments to distributors 34,830 34,493 Inventory valuation 12,082 9,605 Net operating loss carryforward 63,209 105,756 Capital loss carryforward 5,707 4,582 Share-based compensation 31,410 26,780 Income tax credits 100,294 115,893 Property, plant and equipment, principally due to differences in depreciation 16,262 2,236 Accrued expenses and other 7,559 671 Gross deferred tax assets 283,995 310,881 Valuation allowances (161,834 ) (116,482 ) Deferred tax assets, net of valuation allowances 122,161 194,399 Deferred tax liabilities: Convertible debentures (496,626 ) (493,897 ) Other (9,922 ) (10,649 ) Deferred tax liabilities (506,548 ) (504,546 ) Net deferred tax liability $ (384,387 ) $ (310,147 ) Reported as: Current deferred tax assets $ — $ 71,045 Non-current deferred tax assets 14,831 — Non-current deferred tax liability (399,218 ) (381,192 ) Net deferred tax liability $ (384,387 ) $ (310,147 ) In addition to the deferred tax assets listed above, the Company has unrecorded tax benefits of $ 47.3 million attributable to the difference between the amount of the financial statement expense and the allowable tax deduction associated with share-based compensation. As a result of net operating loss (NOL) carryforwards, the Company was not able to recognize the excess tax benefits of share-based compensation deductions because the deductions did not reduce income tax payable. Although not recognized for financial reporting purposes, this unrecorded tax benefit is available to reduce future income and is incorporated into the disclosed amounts of the Company's federal and state NOL carryforwards, discussed below. If subsequently realized, the benefit will be recorded to contributed capital. In assessing whether it is more likely than not that deferred tax assets will be realized, the Company considers all available evidence, both positive and negative, including its recent cumulative earnings experience and expectations of future available taxable income of the appropriate character by taxing jurisdiction, tax attribute carryback and carryforward periods available to them for tax reporting purposes, and prudent and feasible tax planning strategies. The Company had federal, state and foreign NOL carryforwards with an estimated tax effect of $ 99.5 million available at March 31, 2016 . The federal and state NOL carryforwards expire at various times between 2016 and 2035 . The Company believes that it is more likely than not that the benefit from certain foreign and state NOL carryforwards will not be realized. In recognition of this risk, at March 31, 2016 , the Company has provided a valuation allowance of $ 53.2 million . The Company also has state tax credits with an estimated tax effect of $ 80.5 million available at March 31, 2016 . These state tax credits expire at various times between 2016 and 2036 . The Company believes that it is more likely than not that the full benefit from these state tax credits will not be realized, and therefore has provided a valuation allowance of $ 55.6 million . The Company has capital loss carryforwards with an estimated tax effect of $ 5.7 million available at March 31, 2016. These capital loss carryforwards begin to expire in 2020 . The Company believes that it is more likely than not that the full benefit from these capital losses will not be realized, and therefore has provided a valuation allowance of $ 5.7 million . The Company had U.S foreign tax credits with an estimated tax effect of $ 25.8 million that expire at various times between 2016 and 2026 . The Company believes it is more likely than not that the benefit from these credits will not be fully realized and has provided a valuation allowance of $ 25.2 million . At March 31, 2016 , the Company had credits for increasing research activity in the amount of $ 72.7 million that expire at various times between 2022 and 2036 . At March 31, 2016, the Company had $ 4.3 million of alternative minimum tax credits that do not expire. In addition, the Company had $ 20.0 million of withholding tax credits that expire at various times between 2022 and 2024 in foreign jurisdictions. The Company believes it is more likely than not that the benefit from these credits will not be fully realized and has provided a valuation allowance of $ 20.0 million . During the year ended March 31, 2016, the H.R. 2029 "Protecting Americans from Tax Hikes Act of 2015" was signed into law which extended certain business tax provisions through December 31, 2019, including IRC section 954(c)(6) dealing with the application of Subpart F to certain inter-company payments among controlled foreign corporations. The expiration of section 954(c)(6) and the other expired provisions could have a material impact on the Company's consolidated results of operations subsequent to the year ended March 31, 2020. The Company recognizes interest and penalties related to unrecognized tax benefits through income tax expense. The Company is subject to income taxes in the U.S. and numerous foreign jurisdictions. The Company files U.S. federal, U.S. state, and foreign income tax returns. For U.S. federal, and in general for U.S. state tax returns, the fiscal 2011 and later tax years remain open for examination by tax authorities. The IRS is currently auditing Microchip's 2011 and 2012 tax years. For foreign tax returns, the Company is generally no longer subject to income tax examinations for years prior to fiscal 2008. Significant judgment is required in evaluating the Company's uncertain tax positions and determining its provision for income taxes. Although the Company believes that it has appropriately reserved for its uncertain tax positions, no assurance can be given that the final tax outcome of these matters will not be different than expectations. The Company will adjust these reserves in light of changing facts and circumstances, such as the closing of a tax audit, the refinement of an estimate, the closing of a statutory audit period or changes in applicable tax law. To the extent that the final tax outcome of these matters is different than the amounts recorded, such differences could impact the provision for income taxes in the period in which such determination is made. The provision for income taxes includes the impact of reserve provisions and changes to the reserves that are considered appropriate, as well as related net interest. The Company recognizes liabilities for anticipated tax audit issues in the U.S. and other domestic and international tax jurisdictions based on its estimate of whether, and the extent to which, additional tax payments are more likely than not. The Company believes that it has appropriate support for the income tax positions taken and to be taken on its tax returns and that its accruals for tax liabilities are adequate for all open years based on an assessment of many factors including past experience and interpretations of tax law applied to the facts of each matter. The Company believes it maintains appropriate reserves to offset any potential income tax liabilities that may arise upon final resolution of matters for open tax years. If such reserve amounts ultimately prove to be unnecessary, the resulting reversal of such reserves could result in tax benefits being recorded in the period the reserves are no longer deemed necessary. If such amounts prove to be less than an ultimate assessment, a future charge to expense would be recorded in the period in which the assessment is determined. Although the timing of the resolution or closure of audits is highly uncertain, the Company does not believe that it is reasonably possible that the unrecognized tax benefits would materially change in the next 12 months. The following table summarizes the activity related to the Company's gross unrecognized tax benefits from April 1, 2013 to March 31, 2016 (amounts in thousands): Year Ended March 31, 2016 2015 2014 Beginning balance $ 170,654 $ 149,878 $ 152,845 Increases related to acquisitions 46,245 8,381 341 Decreases related to settlements with tax authorities (7,954 ) (20,197 ) (15,016 ) Decreases related to statute of limitation expirations (4,591 ) (9,031 ) (4,069 ) Increases related to current year tax positions 16,315 23,179 14,669 Increases related to prior year tax positions — 18,444 1,108 Ending balance $ 220,669 $ 170,654 $ 149,878 As of March 31, 2016 , the Company had accrued approximately $ 2.4 million related to the potential payment of interest on the Company's uncertain tax positions. As of March 31, 2015 , the Company had accrued approximately $ 0.7 million related to the potential payment of interest on the Company's uncertain tax positions. Interest was included in the provision for income taxes. The Company has accrued for approximately $ 27.6 million in penalties related to its uncertain tax positions related to its international locations as of March 31, 2016 and March 31, 2015 . Interest and penalties charged or (credited) to operations during the years ended March 31, 2016 , 2015 and 2014 related to the Company's uncertain tax positions were $ 1.7 million , $ (1.8) million and $ 0.2 million , respectively. The increase related to prior year tax positions for March 31, 2015 related primarily to a balance sheet reclassification from a valuation allowance to a reserve in the amount of $ 15.7 million .

1.625% Senior Subordinated Conv

1.625% Senior Subordinated Convertible Debentures (Notes)	12 Months Ended
	Mar. 31, 2016
Senior Subordinated Convertible Debenture Due 2025 [Member]
Debt Instrument [Line Items]
Senior subordinated convertible debentures	1.625% SENIOR SUBORDINATED CONVERTIBLE DEBENTURES In February 2015, the Company issued $ 1,725.0 million principal amount of 1.625% senior subordinated convertible debentures due February 15, 2025 . The debentures are subordinated to the Company's senior debt, including amounts borrowed under its amended credit facility, but are senior to the Company's outstanding 2.125% junior subordinated convertible debentures. The debentures are convertible, subject to certain conditions, into cash, shares of the Company's common stock or a combination thereof, at the Company's election, at an initial base conversion rate of 14.5654 shares of common stock per $ 1,000 principal amount of debentures, representing an initial base conversion price of approximately $ 68.66 per share of common stock. As a result of cash dividends paid since the issuance of the debentures, the conversion rate has been adjusted to 15.1396 shares of common stock per $ 1,000 of principal amount of debentures, representing a base conversion price of approximately $ 66.05 per share of common stock. In addition, if at the time of conversion the applicable price of the Company's common stock exceeds the base conversion price, the conversion rate will be increased by up to an additional initial base conversion rate of 7.2827 shares of common stock per $ 1,000 principal amount of debentures, as determined pursuant to a specified formula. As a result of cash dividends paid since the issuance of the debentures, the maximum number of additional shares that may be issued if the stock price of the Company's common stock exceeds the base conversion price has been adjusted to 7.5698 shares of common stock per $ 1,000 principal amount of debentures. However, in no event will the conversion rate exceed 20.3915 (adjusted to 21.1954 as a result of cash dividends paid since the issuance of the debentures) shares of common stock per $ 1,000 principal amount of debentures. The Company received net proceeds of approximately $ 1,694.7 million from the issuance of its senior subordinated convertible debentures after deduction of issuance costs of approximately $ 30.3 million . The $ 30.3 million in issuance costs was split between a debt component of $ 20.4 million and an equity component of $ 9.9 million . The $ 20.4 million in debt issuance costs is recorded in other assets and is being amortized using the effective interest method over the term of the debentures. Prior to the close of business on the business day immediately preceding November 15, 2024, the debentures will be convertible at the option of the debenture holders only upon the satisfaction of specified conditions and during certain periods. Thereafter until close of business on the second scheduled trading day immediately preceding February 15, 2025, the debentures will be convertible at the option of the debenture holders at any time regardless of these conditions. Accrued and unpaid interest will be considered fully paid upon settlement of shares. As the debentures can be settled in cash upon conversion, for accounting purposes, the debentures were bifurcated into a liability component and an equity component, which are both initially recorded at fair value. The carrying value of the equity component at March 31, 2016 and March 31, 2015 was $ 564.9 million . The estimated fair value of the liability component of the debentures at the issuance date was $1,160.1 million resulting in a debt discount of $ 564.9 million . The unamortized debt discount was $ 490.3 million at March 31, 2016 and $ 559.3 million at March 31, 2015 . The remaining period over which the unamortized debt discount will be recognized as non-cash interest expense is 8.87 years . In fiscal 2016 , the Company recognized $ 42.6 million in non-cash interest expense related to the amortization of the debt discount compared to $ 5.7 million in fiscal 2015 . The Company recognized $ 28.0 million of interest expense related to the 1.625% coupon on the debentures in fiscal 2016 compared to $ 3.8 million in fiscal 2015 . The effective interest rate of the debentures is 5.9% .

2.125% Junior subordinated conv

2.125% Junior subordinated convertible debentures (Notes)	12 Months Ended
	Mar. 31, 2016
Junior Subordinated Convertible Debentures Due2037 Member
Debt Instrument [Line Items]
Junior subordinated convertible debentures	2.125% JUNIOR SUBORDINATED CONVERTIBLE DEBENTURES In February 2015, the Company acquired $ 575.0 million in aggregate principal amount of its 2.125% junior subordinated convertible debentures for an aggregate purchase price of $ 1,134.6 million , based on market value. The payment was allocated between the liability ($ 238.3 million ) and equity ($ 896.3 million ) components of the convertible debentures, using the equivalent rate that reflected the borrowing rate for a similar non-convertible debt prior to the retirement. The transaction resulted in a loss on retirement of convertible debentures of approximately $ 50.6 million , which represented the difference between the fair value of the liability component at time of repurchase and the sum of the carrying values of the debt component and any unamortized debt issuance costs. The Company's remaining $ 575.0 million principal amount of 2.125% junior subordinated convertible debentures due December 15, 2037 , are subordinated in right of payment to any future senior debt of the Company (including the Company's senior subordinated convertible debentures) and are effectively subordinated in right of payment to the liabilities of the Company's subsidiaries. The debentures are convertible, subject to certain conditions, into cash, shares of the Company's common stock or a combination thereof, at the Company's election, at an initial conversion rate of 29.2783 shares of common stock per $ 1,000 principal amount of debentures, representing an initial conversion price of approximately $ 34.16 per share of common stock. As of March 31, 2016 , the holders of the debentures had the right to convert their debentures between April 1, 2016 and June 30, 2016 because for at least 20 trading days during the 30 consecutive trading day period ending on March 31, 2016 , the Company's common stock had a last reported sale price greater than 130% of the conversion price. As of March 31, 2016, the Company has classified the junior subordinated convertible debentures as long-term on the consolidated balance sheets as the Company has the intent and ability to refinance the obligation on a long-term basis. As of March 31, 2016 , a holder could realize more economic value by selling its debentures in the over the counter market than from converting its debentures. As a result of cash dividends paid since the issuance of the debentures, the conversion rate has been adjusted to 41.1350 shares of common stock per $ 1,000 of principal amount of debentures, representing a conversion price of approximately $ 24.31 per share of common stock. The if-converted value of the debentures exceeded the principal amount by $ 565.1 million at March 31, 2016 . The debentures include a contingent interest mechanism that begins in December 2017. The terms of the contingent interest include a 0.25% additional interest rate if the debentures are trading at less than $400 and a 0.5% additional interest rate if the debentures are trading at greater than $1,500 . Based on the current trading price of the debentures, the contingent interest rate beginning in December 2017 would be 0.5% of the average trading price. As the debentures can be settled in cash upon conversion, for accounting purposes, the debentures were bifurcated into a liability component and an equity component, which were both initially recorded at fair value. The carrying value of the equity component at March 31, 2016 and March 31, 2015 was $ 411.2 million . The estimated fair value of the liability component of the debentures at the issuance date was $163.8 million , resulting in a debt discount of $ 411.2 million . The unamortized debt discount was $ 378.3 million at March 31, 2016 and $ 383.7 million at March 31, 2015 . The remaining period over which the unamortized debt discount will be recognized as non-cash interest expense is 21.75 years. In the years ended March 31, 2016 , 2015 and 2014 , the Company recognized $ 5.4 million , $ 9.1 million and $ 9.0 million , respectively, in non-cash interest expense related to the amortization of the debt discount. The Company recognized $ 12.2 million , $ 22.8 million and $ 24.4 million of interest expense related to the 2.125% coupon on the debentures in fiscal 2016 , 2015 and 2014 , respectively. The effective interest rate of the debentures is 9.1% .

Credit facility (Notes)

Credit facility (Notes)	12 Months Ended
	Mar. 31, 2016
Credit Facility [Abstract]
Credit Facility	CREDIT FACILITY In February 2015, the Company amended its existing $2.0 billion credit agreement by increasing the revolving credit facility to $ 2.555 billion and removing the term loan portion of the agreement. The new credit agreement includes two tranches. One tranche consists of bank commitments through February 2020 and another tranche consists of bank commitments through June 2018, the maturity date of the original credit agreement. The increase option permitting the Company, subject to certain requirements, to arrange with existing lenders or new lenders to provide up to an aggregate of $300 million in additional commitments, was also adjusted to $ 249.4 million . The credit agreement provides for a $ 125 million foreign currency sublimit, a $ 25 million letter of credit sublimit and a $25 million swingline loan sublimit. The amended credit agreement was accounted for as a modification and as such any remaining unamortized deferred costs associated with the prior credit agreement was associated with the new agreement since the borrowing capacity was increased. At March 31, 2016 , $ 1,052.0 million of revolving credit facility borrowings were outstanding under the credit agreement compared to $ 462.0 million at March 31, 2015 . In December 2015, the Company secured additional revolving credit commitments of $ 219 million from various banks in the February 2020 tranche under the increase option of the credit agreement, bringing its revolving credit facility to $ 2.774 billion . The remaining increase option was $ 30.4 million as of March 31, 2016 . In December 2015, the Company amended the Maximum Total Leverage Ratio in Section 6.11 of its existing credit agreement to allow the Total Leverage Ratio to be temporarily increased to 5.00 to 1.00 for a period of four consecutive quarters in conjunction with a Permitted Acquisition occurring during the first of the four quarters. The Total Leverage Ratio then decreases to 4.75 to 1.00 for three consecutive quarters, finally returning to the stated 4.50 to 1.00 Total Leverage Ratio of the credit agreement after a period of seven consecutive fiscal periods. The Company can elect to use this special feature, also referred to as an Adjusted Covenant Period, no more than two times during the term of the credit agreement and also can terminate an Adjusted Covenant Period earlier than the seven consecutive quarters allowed. The loans under the credit agreement bear interest, at the Company's option, at the base rate plus a spread of 0.25% to 1.25% or an adjusted LIBOR rate (based on one, two, three, or six-month interest periods) plus a spread of 1.25% to 2.25% , in each case with such spread being determined based on the consolidated leverage ratio for the preceding four fiscal quarters (in the case of the 2018 tranche revolving loans) or the consolidated senior leverage ratio (in the case of the 2020 tranche revolving loans). The base rate means the highest of JPMorgan Chase Bank, N.A.'s prime rate, the federal funds rate plus a margin equal to 0.50% and the adjusted LIBOR rate for a 1-month interest period plus a margin equal to 1.00% . Swingline loans accrue interest at a per annum rate based on the base rate plus the applicable margin for base rate loans. Base rate loans may only be made in U.S. Dollars. The Company is also obligated to pay other customary administration fees and letter of credit fees for a credit facility of this size and type. Interest is due and payable in arrears quarterly for loans bearing interest at the base rate and at the end of an interest period (or at each three-month interval in the case of loans with interest periods greater than three months) in the case of loans bearing interest at the adjusted LIBOR rate. Interest expense related to the credit agreement was approximately $18.9 million in fiscal 2016 , approximately $19.9 million in fiscal 2015 and approximately $ 14.6 million in fiscal 2014 . Principal, together with all accrued and unpaid interest, is due and payable on the respective tranche maturity date, which is June 27, 2018 and February 4, 2020. The weighted average interest rate on short-term borrowings outstanding at March 31, 2016 related to the credit agreement was 1.94% . The Company also pays a quarterly commitment fee on the available but unused portion of its line of credit which is calculated on the average daily available balance during the period. The Company may prepay the loans and terminate the commitments, in whole or in part, at any time without premium or penalty, subject to certain conditions including minimum amounts in the case of commitment reductions and reimbursement of certain costs in the case of prepayments of LIBOR loans. The Company's obligations under the credit agreement are guaranteed by certain of its subsidiaries meeting materiality thresholds set forth in the credit agreement. To secure the Company's obligations under the credit agreement, the Company and its domestic subsidiaries are required to pledge the equity securities of certain of their respective material subsidiaries, subject to certain exceptions and limitations. The credit agreement contains customary affirmative and negative covenants, including covenants that limit or restrict the Company and its subsidiaries' ability to, among other things, incur subsidiary indebtedness, grant liens, merge or consolidate, dispose of assets, make investments, make acquisitions, enter into certain transactions with affiliates, pay dividends or make distributions, repurchase stock, enter into restrictive agreements and enter into sale and leaseback transactions, in each case subject to customary exceptions for a credit facility of this size and type. The Company is also required to maintain compliance with consolidated senior and total leverage ratios and a consolidated interest coverage ratio. At March 31, 2016 , the Company was in compliance with these covenants. The credit agreement includes customary events of default that include, among other things, non-payment defaults, inaccuracy of representations and warranties, covenant defaults, cross default to material indebtedness, bankruptcy and insolvency defaults, material judgment defaults, ERISA defaults and a change of control default. The occurrence of an event of default could result in the acceleration of the obligations under the credit agreement. Under certain circumstances, a default interest rate will apply on all obligations during the existence of an event of default under the credit agreement at a per annum rate equal to 2.00% above the applicable interest rate for any overdue principal and 2.00% above the rate applicable for base rate loans for any other overdue amounts.

Contingencies (Notes)

Contingencies (Notes)	12 Months Ended
	Mar. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Contingencies	CONTINGENCIES In the ordinary course of the Company's business, the Company is involved in a limited number of legal actions, both as plaintiff and defendant. Consequently, the Company could incur uninsured liability in any of those actions. The Company also periodically receives notifications from various third parties alleging infringement of patents or other intellectual property rights. With respect to pending legal actions to which the Company is a party, although the outcomes of these actions are generally not determinable, the Company believes that the ultimate resolution of these matters will not harm its business and will not have a material adverse effect on its financial position, cash flows or results of operations. However, if an unfavorable ruling were to occur in any of the legal proceedings described in Note 28 or in other legal proceedings that were not deemed material to the Company as of the date hereof, then such legal proceedings could have a material adverse effect on the Company's financial position, cash flows or results of operations. Litigation relating to the semiconductor industry is not uncommon, and the Company is, from time to time, subject to such litigation. As a result, no assurances can be given with respect to the extent or outcome of any such litigation in the future. The Company's technology license agreements generally include an indemnification clause that indemnifies the licensee against liability and damages (including legal defense costs) arising from any claims of patent, copyright, trademark or trade secret infringement by the Company's proprietary technology. The terms of these indemnification provisions approximate the terms of the outgoing technology license agreements, which are typically perpetual unless terminated by either party for breach. The possible amount of future payments the Company could be required to make based on agreements that specify indemnification limits, if such indemnifications were required on all of these agreements, is approximately $ 142.7 million . There are some licensing agreements in place that do not specify indemnification limits. The Company had not recorded any liabilities related to these indemnification obligations as of March 31, 2016 .

Stock Repurchase Activity (Note

Stock Repurchase Activity (Notes)	12 Months Ended
	Mar. 31, 2016
Equity [Abstract]
Treasury Stock	STOCK REPURCHASE ACTIVITY In December 2007 , the Company announced that its Board of Directors had authorized the repurchase of up to 10.0 million shares of its common stock in the open market or in privately negotiated transactions. As of March 31, 2015, the Company had repurchased 7.5 million shares under this authorization for $ 234.7 million . In May 2015, the Company's Board of Directors authorized an increase to the existing share repurchase program to 20.0 million shares of common stock from the approximately 2.5 million shares remaining under the prior authorization. During fiscal 2016, the Company repurchased 8.6 million shares under this authorization for $ 363.8 million . In January 2016, the Company's Board of Directors authorized an increase to the existing share repurchase program to 15.0 million shares of common stock from the approximately 11.4 million shares remaining under the prior authorization. There is no expiration date associated with this repurchase program. During the years ended March 31, 2015 and 2014 , the Company did not purchase any of its shares of common stock.

Employee Benefit Plans (Notes)

Employee Benefit Plans (Notes)	12 Months Ended
	Mar. 31, 2016
Compensation and Retirement Disclosure [Abstract]
Employee Benefit Plans [Text Block]	EMPLOYEE BENEFIT PLANS The Company maintains a contributory profit-sharing plan for its domestic employees meeting certain eligibility and service requirements. The plan qualifies under Section 401(k) of the Internal Revenue Code of 1986, as amended, and allows employees to contribute up to 60% of their base salary, subject to maximum annual limitations prescribed by the IRS. The Company has a discretionary matching contribution program. All matches are provided on a quarterly basis and require the participant to be an active employee at the end of the applicable quarter. During fiscal 2016 , 2015 and 2014 , the Company's matching contributions to the plan totaled $ 4.4 million , $ 3.9 million and $ 3.6 million , respectively. The Company's 2001 Employee Stock Purchase Plan (the 2001 Purchase Plan) became effective on March 1, 2002 . Under the 2001 Purchase Plan, eligible employees of the Company may purchase shares of common stock at semi-annual intervals through periodic payroll deductions. The purchase price in general will be 85% of the lower of the fair market value of the common stock on the first day of the participant's entry date into the offering period or of the fair market value on the semi-annual purchase date. Depending upon a participant's entry date into the 2001 Purchase Plan, purchase periods under the 2001 Purchase Plan consist of overlapping periods of either 24 , 18 , 12 or 6 months in duration. In May 2003 and August 2003 , the Company's Board and stockholders, respectively, each approved an annual automatic increase in the number of shares reserved under the 2001 Purchase Plan. The automatic increase took effect on January 1, 2005 , and on each January 1 thereafter during the term of the plan, and is equal to the lesser of (i) 1,500,000 , (ii) one half of one percent ( 0.5% ) of the then outstanding shares of the Company's common stock, or (iii) such lesser amount as is approved by Board of Directors . On January 1, 2016, an additional 1,017,492 shares were reserved under the 2001 Purchase Plan based on the automatic increase. Upon the approval of the Board of Directors, there were no shares added under the 2001 Purchase Plan on January 1, 2015 or 2014 based on the automatic increase provision. Since the inception of the 2001 Purchase Plan, 12,295,354 shares of common stock have been reserved for issuance and 6,651,710 shares have been issued under this purchase plan. During fiscal 1995, a purchase plan was adopted for employees in non-U.S. locations. Such plan provided for the purchase price per share to be 100% of the lower of the fair market value of the common stock at the beginning or end of the semi-annual purchase plan period. Effective May 1, 2006, the Company's Board of Directors approved a purchase price per share equal to 85% of the lower of the fair market value of the common stock at the beginning or end of the semi-annual purchase plan period. On May 1, 2006, the Company's Board of Directors approved an annual automatic increase in the number of shares reserved under the plan. The automatic increase took effect on January 1, 2007, and on each January 1 thereafter during the term of the plan, and is equal to one tenth of one percent (0.1%) of the then outstanding shares of the Company's common stock. On January 1, 2016, an additional 203,498 shares were reserved under the plan based on the automatic increase. Upon the approval of the Board of Directors, there were no shares added under the plan on January 1, 2015 or 2014, based on the automatic increase provision. Since the inception of this purchase plan, 1,703,783 shares of common stock have been reserved for issuance and 1,063,360 shares have been issued under this purchase plan. Effective January 1, 1997 , the Company adopted a non-qualified deferred compensation arrangement. This plan is unfunded and is maintained primarily for the purpose of providing deferred compensation for a select group of highly compensated employees as defined in ERISA Sections 201, 301 and 401. There are no Company matching contributions made under this plan. In connection with the acquisition of SMSC in August 2012, the Company assumed an unfunded Supplemental Executive Retirement Plan ("SERP"), which provides former SMSC senior management with retirement, disability and death benefits. An amendment to the SERP was executed on November 3, 2009, freezing the benefit level for existing participants as of February 28, 2010 and closing the SERP to new participants. As of March 31, 2016 , the projected benefit obligation is $ 5.2 million . Annual benefit payments and contributions under this plan are expected to be approximately $ 0.7 million in fiscal 2017 and approximately $ 3.8 million cumulatively in fiscal 2018 through fiscal 2026. The Company has management incentive compensation plans which provide for bonus payments, based on a percentage of base salary, from an incentive pool created from operating profits of the Company, at the discretion of the Board of Directors. During fiscal 2016 , 2015 and 2014 , $ 19.1 million , $ 24.2 million and $ 24.4 million were charged against operations for these plans, respectively. The Company also has a plan that, at the discretion of the Board of Directors, provides a cash bonus to all employees of the Company based on the operating profits of the Company. During fiscal 2016 , 2015 and 2014 , $ 14.2 million , $ 15.9 million and $ 15.2 million , respectively, were charged against operations for this plan.

Equity Incentive Plans (Notes)

Equity Incentive Plans (Notes)	12 Months Ended
	Mar. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Equity incentive plans	EQUITY INCENTIVE PLANS Share-Based Compensation Expense The following table presents the details of the Company's share-based compensation expense (amounts in thousands): Year Ended March 31, 2016 2015 2014 Cost of sales $ 8,252 (1) $ 9,010 (1) $ 7,340 (1) Research and development 32,022 28,164 24,554 Selling, general and administrative 31,146 21,422 21,893 Pre-tax effect of share-based compensation 71,420 58,596 53,787 Income tax benefit 23,012 10,640 5,722 Net income effect of share-based compensation $ 48,408 $ 47,956 $ 48,065 (1) During the year ended March 31, 2016 , $ 7.9 million of share-based compensation expense was capitalized to inventory, and $ 8.3 million of previously capitalized share-based compensation expense in inventory was sold. During the year ended March 31, 2015 , $ 6.8 million of share-based compensation expense was capitalized to inventory, and $ 9.0 million of previously capitalized share-based compensation expense in inventory was sold. During the year ended March 31, 2014 , $ 7.4 million of share-based compensation expense was capitalized to inventory, and $ 7.3 million of previously capitalized share-based compensation expense in inventory was sold. The amount of unearned share-based compensation currently estimated to be expensed in the remainder of fiscal 2017 through fiscal 2021 related to unvested share-based payment awards at March 31, 2016 is $ 134.5 million . The weighted average period over which the unearned share-based compensation is expected to be recognized is approximately 2.30 years. Combined Incentive Plan Information RSU share activity under the 2004 Plan is set forth below: Number of Shares Nonvested shares at April 1, 2013 6,009,831 Granted 1,616,632 Forfeited/expired (282,964 ) Vested (1,813,465 ) Nonvested shares at March 31, 2014 5,530,034 Granted 1,446,968 Forfeited/expired (266,415 ) Vested (1,441,671 ) Nonvested shares at March 31, 2015 5,268,916 Granted 2,479,729 Assumed upon acquisition 525,442 Forfeited/expired (360,072 ) Vested (1,606,273 ) Nonvested shares at March 31, 2016 6,307,742 The total intrinsic value of RSUs which vested during the years ended March 31, 2016 , 2015 and 2014 was $ 72.1 million , $ 67.6 million and $ 74.6 million , respectively. The aggregate intrinsic value of RSUs outstanding at March 31, 2016 was $ 304.0 million , calculated based on the closing price of the Company's common stock of $48.20 per share on March 31, 2016 . At March 31, 2016 , the weighted average remaining expense recognition period was 2.35 years. The weighted average fair value per share of the RSUs awarded is calculated based on the fair market value of the Company's common stock on the respective grant dates discounted for the Company's expected dividend yield. The weighted average fair value per share of RSUs awarded in fiscal 2016 , 2015 and 2014 was $ 38.92 , $ 42.02 and $ 34.24 , respectively. Stock option and stock appreciation right (SAR) activity under the Company's stock incentive plans in the three years ended March 31, 2016 is set forth below: Number of Shares Weighted Average Exercise Price per Share Outstanding at April 1, 2013 2,269,803 $ 25.58 Granted — — Exercised (1,675,663 ) 25.91 Canceled (20,529 ) 22.78 Outstanding at March 31, 2014 573,611 24.75 Granted 27,654 46.66 Assumed upon acquisition 666,586 29.33 Exercised (477,618 ) 26.42 Canceled (105,934 ) 28.17 Outstanding at March 31, 2015 684,299 28.41 Granted 244 41.09 Assumed upon acquisition 604,900 35.03 Exercised (221,987 ) 25.30 Canceled (153,948 ) 31.52 Outstanding at March 31, 2016 913,508 $ 33.00 The total intrinsic value of options and SARs exercised during the years ended March 31, 2016 , 2015 and 2014 was $ 4.7 million , $ 9.6 million and $ 25.5 million , respectively. This intrinsic value represents the difference between the fair market value of the Company's common stock on the date of exercise and the exercise price of each equity award. The aggregate intrinsic value of options and SARs outstanding at March 31, 2016 was $ 13.9 million . The aggregate intrinsic value of options and SARS exercisable at March 31, 2016 was $ 8.8 million . The aggregate intrinsic values were calculated based on the closing price of the Company's common stock of $48.20 per share on March 31, 2016 . As of March 31, 2016 and 2015 , the number of option and SAR shares exercisable was 553,844 and 283,133 , respectively, and the weighted average exercise price per share was $ 32.33 and $ 26.90 , respectively. The weighted average fair values per share of stock options granted in the years ended March 31, 2016 and 2015 was $ 8.85 and $ 9.00 , respectively. The fair values per share of stock options granted in the years ended March 31, 2016 and 2015 were estimated utilizing the following assumptions: Year Ended March 31, 2016 2015 Expected term (in years) 6.5 6.5 Volatility 29.50 % 26.65 % Risk-free interest rate 1.54 % 1.59 % Dividend yield 3.00 % 3.00 % There were no stock options granted in the year ended March 31, 2014 .

Commitments (Notes)

Commitments (Notes)	12 Months Ended
	Mar. 31, 2016
Commitments [Abstract]
Commitments	COMMITMENTS The Company leases office space, a manufacturing facility, and transportation and other equipment under operating leases which expire at various dates through March 31, 2022. The future minimum lease commitments under these operating leases at March 31, 2016 were as follows (amounts in thousands): Year Ending March 31, Amount 2017 $ 16,370 2018 12,350 2019 7,677 2020 3,098 2021 1,000 Thereafter 667 Total minimum payments $ 41,162 Rental expense under operating leases totaled $ 23.3 million , $ 23.8 million and $ 21.5 million for fiscal 2016 , 2015 and 2014 , respectively. Commitments for construction or purchase of property, plant and equipment totaled $ 30.2 million as of March 31, 2016 , all of which will be due within the next year. Other purchase obligations and commitments totaled approximately $ 57.6 million as of March 31, 2016 . Other purchase obligations and commitments include payments due under various types of licenses and approximately $ 52.4 million of outstanding purchase commitments with the Company's wafer foundries for delivery in fiscal 2017 .

Geographic and Segment Informat

Geographic and Segment Information (Notes)	12 Months Ended
	Mar. 31, 2016
Segment Reporting [Abstract]
Segment Reporting Disclosure [Text Block]	GEOGRAPHIC AND SEGMENT INFORMATION The Company's reporting segments include semiconductor products and technology licensing. The Company does not allocate operating expenses, interest income, interest expense, other income or expense, or provision for or benefit from income taxes to these segments for internal reporting purposes, as the Company does not believe that allocating these expenses is beneficial in evaluating segment performance. Additionally, the Company does not allocate assets to segments for internal reporting purposes as it does not manage its segments by such metrics. The following table represents revenues and gross profit for each segment (amounts in thousands): Years ended March 31, 2016 2015 2014 Net Sales Gross Profit Net Sales Gross Profit Net Sales Gross Profit Semiconductor products $ 2,084,210 $ 1,116,340 $ 2,057,443 $ 1,139,971 $ 1,836,639 $ 1,034,165 Technology licensing 89,124 89,124 89,593 89,593 94,578 94,578 Total $ 2,173,334 $ 1,205,464 $ 2,147,036 $ 1,229,564 $ 1,931,217 $ 1,128,743 The Company sells its products to distributors and original equipment manufacturers (OEMs) in a broad range of market segments, performs on-going credit evaluations of its customers and, as deemed necessary, may require collateral, primarily letters of credit. The Company's operations outside the U.S. consist of product assembly and final test facilities in Thailand, and sales and support centers and design centers in certain foreign countries. Domestic operations are responsible for the design, development and wafer fabrication of products, as well as the coordination of production planning and shipping to meet worldwide customer commitments. The Company's Thailand assembly and test facility is reimbursed in relation to value added with respect to assembly and test operations and other functions performed, and certain foreign sales offices receive compensation for sales within their territory. Accordingly, for financial statement purposes, it is not meaningful to segregate sales or operating profits for the assembly and test and foreign sales office operations. Identifiable long-lived assets (consisting of property, plant and equipment net of accumulated amortization) by geographic area are as follows (amounts in thousands): March 31, 2016 2015 United States $ 373,860 $ 331,372 Thailand 182,813 197,981 Various other countries 52,723 52,219 Total long-lived assets $ 609,396 $ 581,572 Sales to unaffiliated customers located outside the U.S., primarily in Asia and Europe, aggregated approximately 84% of consolidated net sales for each of fiscal 2016 , 2015 and 2014 . Sales to customers in Europe represented approximately 22% of consolidated net sales for fiscal 2016 and approximately 21% of consolidated net sales for each of fiscal 2015 and 2014 . Sales to customers in Asia represented approximately 59% of consolidated net sales for each of fiscal 2016 and 2015 , and approximately 60% of consolidated net sales for fiscal 2014 . Within Asia, sales into China, including Hong Kong, represented approximately 30% , 28% and 29% of consolidated net sales for fiscal 2016 , 2015 and 2014 , respectively. Sales into Taiwan represented approximately 12% , 14% and 13% of consolidated net sales for fiscal 2016 , 2015 and 2014 , respectively. Sales into any other individual foreign country did not exceed 10% of the Company's net sales for any of the three years presented. No single end customer or distributor accounted for 10% or more of the Company's net sales during fiscal 2016 , 2015 or 2014 .

Derivative Instruments (Notes)

Derivative Instruments (Notes)	12 Months Ended
	Mar. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities Disclosure	DERIVATIVE INSTRUMENTS Freestanding Derivative Forward Contracts The Company has international operations and is thus subject to foreign currency rate fluctuations. To help manage the risk of changes in foreign currency rates, the Company periodically enters into derivative contracts comprised of foreign currency forward contracts to hedge its asset and liability foreign currency exposure and a portion of its foreign currency operating expenses. Approximately 99 % of the Company's sales are U.S. Dollar denominated. Net gains due to foreign exchange rate fluctuations after the effects of hedging activity were $0.7 million during fiscal 2016, compared to net losses of $7.7 million during fiscal 2015 and net gains of $0.4 million during fiscal 2014. As of March 31, 2016 and 2015 , the Company had no foreign currency forward contracts outstanding. The Company recognized an immaterial amount of net realized gains and losses on foreign currency forward contracts in the years ended March 31, 2016 , 2015 and 2014 . Gains and losses from changes in the fair value of these foreign currency forward contracts and foreign currency exchange rate fluctuations are credited or charged to other income (expense). The Company does not apply hedge accounting to its foreign currency derivative instruments. Fair Value Hedges For derivative instruments that are designated and qualify as fair value hedges, the gain or loss on the derivatives as well as the offsetting gain or loss on the hedged item attributable to the hedged risk are recognized in earnings. Interest rate derivative instruments designated as fair value hedges are designed to manage the exposure to interest rate movements and to reduce borrowing costs by converting fixed-rate debt into floating-rate debt. Under these agreements, the Company agrees to exchange, at specified intervals, the difference between the fixed and floating interest amounts calculated by reference to an agreed-upon notional principal amount. In March 2015, the Company entered into ten-year fixed-to-floating interest rate swap agreements designated as fair value hedges of the changes in fair value of a portion of the Company's fixed-rate 1.625% senior subordinated convertible debentures due to changes in the LIBOR swap rate, the designated benchmark interest rate. The Company pays variable interest equal to the three-month LIBOR minus 53.6 basis points and it receives a fixed interest rate of 1.625%. The notional amount of these contracts outstanding at March 31, 2015 was $ 431.3 million , representing 25% of the principal amount of the senior subordinated convertible debentures. In February 2016, the Company terminated its interest rate swap agreements. Upon termination, the contracts were in an asset position, resulting in cash receipts of approximately $ 25.7 million , which included $3.7 million of accrued interest. The gain from terminating the interest rate swap agreements increased the outstanding balance of the 1.625% senior convertible debentures and is being amortized as a reduction of interest expense over the remaining life of the debentures. The cash flows from the termination of these interest rate swap agreements have been reported as operating activities in the consolidated statements of cash flows. The following table summarizes the location and fair value amounts of derivative instruments reported in the consolidated balance sheets at March 31, 2015 (amounts in thousands): Asset Derivatives Derivatives designated as hedging instruments Balance Sheet Location Fair Value Interest rate contracts Other assets $ 8,928 The following table summarizes the location and amount of the gain or loss on the hedged item attributable to the changes in the LIBOR swap rate and the offsetting gain or loss on the related interest rate swap agreements for the years ended March 31, 2016 and 2015. The difference represents hedge ineffectiveness (amounts in thousands): Year ended March 31, 2016 2015 Income Statement Classification Gain (Loss) on Senior Subordinated Convertible Debentures Gain (Loss) on Interest Rate Swap Gain (Loss) on Senior Subordinated Convertible Debentures Gain (Loss) on Interest Rate Swap Other income (expense) $ (18,060 ) $ 16,345 $ (8,302 ) $ 8,928

Net income per common share att

Net income per common share attributable to Microchip Technology Stockholders (Notes)	12 Months Ended
	Mar. 31, 2016
Earnings Per Share [Abstract]
Net income per common share	NET INCOME PER COMMON SHARE ATTRIBUTABLE TO MICROCHIP TECHNOLOGY STOCKHOLDERS The following table sets forth the computation of basic and diluted net income per common share (in thousands, except per share amounts): Year ended March 31, 2016 2015 2014 Net income attributable to Microchip Technology $ 324,132 $ 369,009 $ 395,281 Weighted average common shares outstanding 203,384 200,937 198,291 Dilutive effect of stock options and RSUs 3,350 3,642 3,910 Dilutive effect of 2037 junior subordinated convertible debentures 10,654 18,982 15,429 Weighted average common and potential common shares outstanding 217,388 223,561 217,630 Basic net income per common share attributable to Microchip Technology stockholders $ 1.59 $ 1.84 $ 1.99 Diluted net income per common share attributable to Microchip Technology stockholders $ 1.49 $ 1.65 $ 1.82 The Company computed basic earnings per common share attributable to its stockholders using net income available to common stockholders and the weighted average number of common shares outstanding during the period. The Company computed diluted earnings per common share attributable to its stockholders using net income available to stockholders and the weighted average number of common shares outstanding plus potentially dilutive common shares outstanding during the period. Potentially dilutive common shares from employee equity incentive plans are determined by applying the treasury stock method to the assumed exercise of outstanding stock options and the assumed vesting of outstanding RSUs. Diluted net income per common share attributable to stockholders for fiscal 2016 , 2015 , and 2014 includes 10,654,070 , 18,982,440 and 15,429,003 shares, respectively, issuable upon the exchange of the Company's 2.125% junior subordinated convertible debentures due December 15, 2037 (see Note 15). The debentures have no impact on diluted net income per common share unless the average price of the Company's common stock exceeds the conversion price because the principal amount of the debentures will be settled in cash upon conversion. Prior to conversion, the Company will include, in the diluted net income per common share calculation, the effect of the additional shares that may be issued when the Company's common stock price exceeds the conversion price using the treasury stock method. The weighted average conversion price per share used in calculating the dilutive effect of the convertible debt for fiscal 2016 , 2015 and 2014 was $ 24.73 , $ 25.48 and $ 26.32 , respectively. There were no shares issuable upon the exchange of the Company's 1.625% senior subordinated convertible debentures due February 15, 2025 (see Note 14). The debentures have no impact on diluted net income per common share unless the average price of the Company's common stock exceeds the conversion price because the principal amount of the debentures will be settled in cash upon conversion. Prior to conversion, the Company will include, in the diluted net income per common share calculation, the effect of the additional shares that may be issued when the Company's common stock price exceeds the conversion price using the treasury stock method. The weighted average conversion price per share used in calculating the dilutive effect of the convertible debt for fiscal 2016 and 2015 was $67.19 and $68.25 , respectively. Weighted average common shares exclude the effect of option shares which are not dilutive. For fiscal 2016 and 2015 , the number of option shares that were antidilutive was 298,015 and 19,305 , respectively. There were no antidilutive option shares for fiscal 2014 .

Quarterly Results (Unaudited)

Quarterly Results (Unaudited)	12 Months Ended
	Mar. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Quarterly Results (Unaudited)	QUARTERLY RESULTS (UNAUDITED) The following table presents the Company's selected unaudited quarterly operating results for the eight quarters ended March 31, 2016 . The Company believes that all adjustments of a normal recurring nature have been made to present fairly the related quarterly results (in thousands, except per share amounts): Fiscal 2016 First Quarter Second Quarter Third Quarter Fourth Quarter Total Net sales $ 533,952 $ 541,391 $ 540,344 $ 557,647 $ 2,173,334 Gross profit 309,017 300,950 292,718 302,779 1,205,464 Operating income 121,319 74,948 76,132 79,946 352,345 Net income 130,460 64,899 61,211 67,355 323,925 Less: Net loss attributable to noncontrolling interests 207 — — — 207 Net income attributable to Microchip Technology 130,667 64,899 61,211 67,355 324,132 Diluted net income per common share attributable to Microchip Technology stockholders 0.60 0.30 0.28 0.31 1.49 Fiscal 2015 First Quarter Second Quarter Third Quarter Fourth Quarter Total Net sales $ 528,876 $ 546,243 $ 528,710 $ 543,207 $ 2,147,036 Gross profit 306,519 307,454 301,959 313,632 1,229,564 Operating income 115,946 101,318 98,009 110,347 425,620 Net income 89,909 92,038 84,798 98,580 365,325 Less: Net loss attributable to noncontrolling interests — 1,603 1,259 822 3,684 Net income attributable to Microchip Technology 89,909 93,641 86,057 99,402 369,009 Diluted net income per common share attributable to Microchip Technology stockholders 0.40 0.42 0.39 0.45 1.65 Refer to Note 3, Special Charges, for an explanation of the special charges included in operating income in fiscal 2016 and fiscal 2015 . Refer to Note 15, 2.125% Junior Subordinated Convertible Debentures, for an explanation of the loss on retirement of convertible debentures of approximately $ 50.6 million included in net income (loss) during the fourth quarter of fiscal 2015. Refer to Note 4, Investments, for an explanation of the net realized gain from sales of available-for-sale marketable equity securities included in net income during the fourth quarter of fiscal 2015 and the first quarter of fiscal 2016.

Supplemental Financial Informat

Supplemental Financial Information (Notes)	12 Months Ended
	Mar. 31, 2016
Supplemental Cash Flow Information [Abstract]
Supplemental Financial Information	SUPPLEMENTAL FINANCIAL INFORMATION Cash paid for income taxes amounted to $ 25.4 million , $ 25.5 million and $ 25.7 million during fiscal 2016 , 2015 and 2014 , respectively. Cash paid for interest on borrowings amounted to $ 52.9 million in fiscal 2016 , $ 40.2 million in fiscal 2015 and $ 34.6 million in fiscal 2014 . A summary of additions and deductions related to the valuation allowance for deferred tax asset accounts for the years ended March 31, 2016 , 2015 and 2014 follows (amounts in thousands): Balance at Beginning of Year Additions Charged to Costs and Expenses Additions Charged to Other Accounts Deductions Balance at End of Year Valuation allowance for deferred tax assets: Fiscal Year 2016 $ 116,482 $ 5,535 $ 47,834 $ (8,017 ) $ 161,834 Fiscal Year 2015 93,811 — 36,957 (14,286 ) 116,482 Fiscal Year 2014 88,637 — 5,174 — 93,811 A summary of additions and deductions related to the allowance for doubtful accounts for the years ended March 31, 2016 , 2015 and 2014 follows (amounts in thousands): Balance at Beginning of Year Additions Charged to Costs and Expenses Deductions (1) Balance at End of Year Allowance for doubtful accounts: Fiscal Year 2016 $ 2,621 $ 59 $ (140 ) $ 2,540 Fiscal Year 2015 2,918 104 (401 ) 2,621 Fiscal Year 2014 2,764 245 (91 ) 2,918 (1) Deductions represent uncollectible accounts written off, net of recoveries. The following tables present the changes in the components of accumulated other comprehensive income (AOCI) for the years ended March 31, 2016 and March 31, 2015 : Year ended March 31, 2016 Unrealized Holding Gains (Losses) Available-for-sale Securities Minimum Pension Liability Foreign Currency Total Balance at March 31, 2015 $ 14,537 $ 13 $ (3,474 ) $ 11,076 Other comprehensive (loss) income before reclassifications (3,241 ) 31 — (3,210 ) Amounts reclassified from accumulated other comprehensive (loss) income (10,948 ) — — (10,948 ) Net other comprehensive (loss) income (14,189 ) 31 — (14,158 ) Purchase of shares from noncontrolling interest — — (275 ) (275 ) Balance at March 31, 2016 $ 348 $ 44 $ (3,749 ) $ (3,357 ) Year ended March 31, 2015 Unrealized Holding Gains (Losses) Available-for-sale Securities Minimum Pension Liability Foreign Currency Total Balance at March 31, 2014 $ (528 ) $ 140 $ 1,439 $ 1,051 Other comprehensive income (loss) before reclassifications 33,759 (127 ) (4,322 ) 29,310 Amounts reclassified from accumulated other comprehensive income (loss) (18,694 ) — — (18,694 ) Net other comprehensive income (loss) 15,065 (127 ) (4,322 ) 10,616 Purchase of shares from noncontrolling interest — — (591 ) (591 ) Balance at March 31, 2015 $ 14,537 $ 13 $ (3,474 ) $ 11,076 The table below details where reclassifications of realized transactions out of AOCI are recorded on the consolidated statements of income. Year ended March 31, Description of AOCI Component 2016 2015 2014 Related Statement of Income Line Unrealized gains on available-for-sale securities $ 10,948 $ 18,706 $ 2,371 Other income Taxes — (12 ) (776 ) Provision for income taxes Reclassification of realized transactions, net of taxes $ 10,948 $ 18,694 $ 1,595 Net Income

Dividends (Notes)

Dividends (Notes)	12 Months Ended
	Mar. 31, 2016
Dividends [Abstract]
Dividends [Text Block]	DIVIDENDS On October 28, 2002, the Company announced that its Board of Directors had approved and instituted a quarterly cash dividend on its common stock. The Company has continued to pay quarterly dividends and has increased the amount of such dividends on a regular basis. Cash dividends paid per share were $ 1.433 , $ 1.425 and $ 1.417 during fiscal 2016 , 2015 and 2014 , respectively. Total dividend payments amounted to $291.1 million , $ 286.5 million and $ 281.2 million during fiscal 2016 , 2015 and 2014 , respectively.

Subsequent Events (Notes)

Subsequent Events (Notes)	12 Months Ended
	Mar. 31, 2016
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS Acquisition of Atmel On April 4, 2016, the Company acquired Atmel, a publicly traded company based in San Jose, California. The Company paid an aggregate of approximately $ 2.98 billion in cash and issued an aggregate of 10.1 million shares of its common stock to Atmel stockholders. The total consideration transferred in the acquisition, including approximately $ 6.7 million of non-cash consideration for the exchange of certain share-based payment awards of Atmel for stock awards of the Company, was approximately $ 3.47 billion . The Company financed the cash portion of the purchase price using approximately $ 2.04 billion of cash, cash equivalents, short-term investments and long-term investments held by certain of its foreign subsidiaries, and approximately $ 0.94 billion from additional borrowings under its existing credit agreement. As a result of the acquisition, Atmel became a wholly owned subsidiary of the Company. Atmel is a worldwide leader in the design and manufacture of microcontrollers, capacitive touch solutions, advanced logic, mixed-signal, nonvolatile memory and RF components. The Company's primary reason for this acquisition was to expand the Company's range of solutions, products and capabilities by extending its served available market. The acquisition was accounted for under the acquisition method of accounting, with the Company identified as the acquirer, and the operating results of Atmel have been included in the Company's consolidated financial statements as of the closing date of the acquisition. Under the acquisition method of accounting, the aggregate amount of consideration paid by the Company was allocated to Atmel's net tangible assets and intangible assets based on their estimated fair values as of April 4, 2016. The excess of the purchase price over the value of the net tangible assets and intangible assets was recorded to goodwill. The factors contributing to the recognition of goodwill were based upon the Company's conclusion that there are strategic and synergistic benefits that are expected to be realized from the acquisition. The goodwill has been allocated to the Company's semiconductor products reporting segment. None of the goodwill related to the Atmel acquisition is deductible for tax purposes. The Company retained an independent third-party appraiser to assist management in its valuation; however, the purchase price allocation has not been finalized. This could result in adjustments to the fair values of the assets acquired and liabilities assumed, the useful lives of intangible assets, the residual amount allocated to goodwill and deferred income taxes recognized. The preliminary allocation of the purchase price is based on the best estimates of management and is subject to revision based on the final valuations and estimates of useful lives. The table below represents the preliminary allocation of the purchase price to the net assets acquired based on their estimated fair values, as well as the associated estimated useful lives of the acquired intangible assets (amounts in thousands). Such amounts were estimated using the most recent audited financial statements of Atmel as of December 31, 2015. The Company does not believe the allocation as of April 4, 2016 will be materially different, however, certain amounts, such as the balances of cash and cash equivalents, accounts receivable, inventories, accounts payable and other current liabilities may vary based upon changes in Atmel’s balances between December 31, 2015 and April 4, 2016, with offsetting changes to goodwill. The Company’s consolidated financial statements as of June 30, 2016 will include updated amounts reflecting the April 4, 2016 estimated fair values. Assets acquired April 4, 2016 Cash and cash equivalents $ 210,252 Accounts receivable, net 195,481 Inventories 403,708 Prepaid expenses and other current assets 35,299 Property, plant and equipment, net 131,154 Goodwill 1,400,814 Purchased intangible assets 1,551,100 Long-term deferred tax assets 157,929 Other assets 45,747 Total assets acquired 4,131,484 Liabilities assumed Accounts payable (59,470 ) Other current liabilities (133,012 ) Long-term line of credit (192,300 ) Deferred tax liabilities (155,553 ) Long-term income tax payable (49,965 ) Other long-term liabilities (67,577 ) Total liabilities assumed (657,877 ) Purchase price allocated $ 3,473,607 Purchased Intangible Assets Useful Life April 4, 2016 (in years) (in thousands) Core/developed technology 10-15 $ 988,400 In-process technology 10-15 114,500 Customer-related 5 435,900 Backlog 1-2 12,300 Total purchased intangible assets $ 1,551,100 Purchased intangible assets include core and developed technology, in-process research and development, customer-related intangibles and acquisition-date backlog. The estimated fair values of the core and developed technology and in-process research and development were determined based on the present value of the expected cash flows to be generated by the respective existing technology or future technology. The core and developed technology intangible assets are being amortized commensurate with the expected cash flows used in the initial determination of fair value. In-process technology is capitalized until such time the related projects are completed or abandoned at which time the capitalized amounts will begin to be amortized or written off. Customer-related intangible assets consist of Atmel's contractual relationships and customer loyalty related to its distributor and end-customer relationships, and the fair values of the customer-related intangibles were determined based on Atmel's projected revenues. An analysis of expected attrition and revenue growth for existing customers was prepared from Atmel's historical customer information. Customer relationships are being amortized in a manner consistent with the estimated cash flows associated with the existing customers and anticipated retention rates. Backlog relates to the value of orders not yet shipped by Atmel at the acquisition date, and the preliminary fair values were based on the estimated profit associated with those orders. Backlog related assets are being recognized commensurate with recognition of the revenue for the orders on which the backlog intangible assets were determined. Amortization expense associated with acquired intangible assets is not deductible for tax purposes. Thus, approximately $ 143.2 million was established as a net deferred tax liability for the future amortization of the intangible assets. No sales or expenses of Atmel were included in the Company’s consolidated statements of income for the year ended March 31, 2016. The following unaudited pro-forma consolidated results of operations for the years ended March 31, 2016 and 2015 assume the Atmel acquisition occurred as of April 1, 2014. The pro-forma adjustments are mainly comprised of acquired inventory fair value costs and amortization of purchased intangible assets. The pro-forma results of operations are presented for informational purposes only and are not indicative of the results of operations that would have been achieved if the acquisition had taken place on April 1, 2014 or of results that may occur in the future (amounts in thousands except per share data): Year ended March 31, 2016 2015 Net sales $ 3,345,790 $ 3,560,370 Net income $ 167,705 $ 116,618 Basic earnings per share $ 0.79 $ 0.55 Diluted earnings per share $ 0.74 $ 0.50 As a result of the Company's acquisition of Atmel, the Company became involved with the following lawsuits. In re: Continental Airbag Products Liability Litigation . On May 11, 2016, an Amended and Consolidated Class Action Complaint ("Complaint") was filed in the United States District Court for the Southern District of Florida (Miami Division) against Atmel, Continental Automotive Systems, Inc., Honda Motor Co., Ltd. and an affiliate, and Daimler AG and an affiliate. The Complaint which includes claims arising under federal law and Florida, California, New Jersey, Michigan and Louisiana state law-alleges that class members unknowingly purchased or leased vehicles containing defective airbag control units (allegedly incorporating defective application specific integrated circuits manufactured by Atmel between 2006 and 2010), and thereby suffered financial harm, including a loss in the value of their purchased or leased vehicles. The plaintiffs are seeking unspecified compensatory and exemplary damages, statutory penalties, pre- and post-judgment interest, attorneys’ fees, and injunctive and other relief. Atmel intends to contest plaintiffs' claims vigorously. Southern District of New York Action by LFoundry Rousset ("LFR") and LFR Employees . On March 4, 2014, LFR and Jean-Yves Guerrini, individually and on behalf of a putative class of LFR employees, filed an action in the United States District Court for the Southern District of New York (the "District Court") against Atmel, its French subsidiary, Atmel Rousset S.A.S. ("Atmel Rousset"), and LFoundry GmbH ("LF"), LFR's German parent. The case purports to relate to Atmel Rousset's June 2010 sale of its wafer manufacturing facility in Rousset, France to LF, and LFR's subsequent insolvency, and later liquidation, more than three years later. The District Court dismissed the case on August 21, 2015, and plaintiffs are appealing the dismissal. Individual Labor Actions by former LFR Employees . In the wake of LFR's insolvency and liquidation, over 500 former employees of LFR have filed individual labor actions against Atmel Rousset in a French labor court. Atmel Rousset believes that each of these actions is entirely devoid of merit, and, further, that any assertion by any of the Claimants of a co-employment relationship with Atmel Rousset is based substantially on the same specious arguments that the Paris Commercial Court summarily rejected in 2014 in related proceedings. Atmel Rousset therefore intends to defend vigorously against each of these claims.

Significant Accounting Polici38

Significant Accounting Policies (Policies)	12 Months Ended
	Mar. 31, 2016
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of Microchip Technology Incorporated and its majority-owned subsidiaries (Microchip or the Company). The Company owned 100% of the outstanding stock in all of its subsidiaries as of March 31, 2016 . As further discussed in Note 2, the Company did not hold 100% of the outstanding common stock of ISSC Technologies Corporation (ISSC) for a period through June 30, 2015. The noncontrolling interest in the Company's net income from ISSC has been excluded from net income attributable to the Company in the Company's consolidated statements of income. All of the Company's subsidiaries are included in the consolidated financial statements. All significant intercompany accounts and transactions have been eliminated in consolidation.
Revenue Recognition	Revenue Recognition The Company recognizes revenue when the earnings process is complete, as evidenced by an agreement with the customer, transfer of title as well as fixed or determinable pricing and when collectability is reasonably assured. The Company recognizes revenue from product sales to original equipment manufacturers (OEMs) upon shipment and records reserves for estimated customer returns. Distributors worldwide generally have broad price protection and product return rights, so the Company defers revenue recognition until the distributor sells the product to their customer. Revenue is recognized when the distributor sells the product to their end customer, at which time the sales price becomes fixed or determinable. Revenue is not recognized upon the Company's shipment to the distributors since, due to discounts from list price as well as price protection rights, the sales price is not substantially fixed or determinable at that time. At the time of shipment to these distributors, the Company records a trade receivable for the selling price as there is a legally enforceable right to payment, relieves inventory for the carrying value of goods shipped since legal title has passed to the distributor, and records the gross margin in deferred income on shipments to distributors on its consolidated balance sheets. Deferred income on shipments to distributors effectively represents gross margin on the sale to the distributor at the initial shipment date; however, the amount of gross margin recognized by the Company in future periods will be less than the deferred margin as a result of credits granted to distributors on specifically identified products and customers to allow the distributors to earn a competitive gross margin on the sale of the Company's products to their end customers and price protection concessions related to market pricing conditions. The Company sells the majority of the items in its product catalog to its distributors worldwide at a uniform list price. However, distributors resell the Company's products to end customers at a very broad range of individually negotiated price points. The majority of the Company's distributors' resales require a reduction from the original list price paid. Often, under these circumstances, the Company remits back to the distributor a portion of their original purchase price after the resale transaction is completed in the form of a credit against the distributors' outstanding accounts receivable balance. The credits are on a per unit basis and are not given to the distributor until they provide information regarding the sale to their end customer. The price reductions vary significantly based on the customer, product, quantity ordered, geographic location and other factors and discounts to a price less than the Company's cost have historically been rare. The effect of granting these credits establishes the net selling price from the Company to its distributors for the product and results in the net revenue recognized by the Company when the product is sold by the distributors to their end customers. Thus, a portion of the "deferred income on shipments to distributors" balance represents the amount of distributors' original purchase price that will be credited back to the distributor in the future. The wide range and variability of negotiated price concessions granted to distributors does not allow the Company to accurately estimate the portion of the balance in the deferred income on shipments to distributors account that will be credited back to the distributors. Therefore, the Company does not reduce deferred income on shipments to distributors or accounts receivable by anticipated future price concessions; rather, price concessions are recorded against deferred income on shipments to distributors when incurred, which is generally at the time the distributor sells the product. At March 31, 2016 , the Company had approximately $ 267.2 million of deferred revenue and $ 83.8 million in deferred cost of sales recognized as $ 183.4 million of deferred income on shipments to distributors. At March 31, 2015 , the Company had approximately $ 260.9 million of deferred revenue and $ 94.8 million in deferred cost of sales recognized as $ 166.1 million of deferred income on shipments to distributors. The deferred income on shipments to distributors that will ultimately be recognized in the Company's income statement will be lower than the amount reflected on the balance sheet due to price credits to be granted to the distributors when the product is sold to their customers. These price credits historically have resulted in the deferred income approximating the overall gross margins that the Company recognizes in the distribution channel of its business. The Company reduces product pricing through price protection based on market conditions, competitive considerations and other factors. Price protection is granted to distributors on the inventory they have on hand at the date the price protection is offered. When the Company reduces the price of its products, it allows the distributor to claim a credit against its outstanding accounts receivable balances based on the new price of the inventory it has on hand as of the date of the price reduction. There is no immediate revenue impact from the price protection, as it is reflected as a reduction of the deferred income on shipments to distributors' balance. Products returned by distributors and subsequently scrapped have historically been immaterial to the Company's consolidated results of operations. The Company routinely evaluates the risk of impairment of the deferred cost of sales component of the deferred income on shipments to distributors' account. Because of the historically immaterial amounts of inventory that have been scrapped, and historically rare instances where discounts given to a distributor result in a price less than the Company's cost, the Company believes the deferred costs have a low risk of material impairment. Shipping charges billed to customers are included in net sales, and the related shipping costs are included in cost of sales. The Company collects and remits certain sales-related taxes on sales of inventory and reports such amounts under the net method in its consolidated statements of income. For licenses or other technology arrangements without an upgrade period, non-royalty revenue from the license is recognized upon delivery of the technology if the fee is fixed or determinable and collection of the fee is reasonably assured. Royalties are recognized when reported to the Company, which generally coincides with the receipt of payment. In certain limited circumstances, the Company enters into license and other arrangements for technologies that the Company is continuing to enhance and refine or under which it is obligated to provide unspecified enhancements. Under these arrangements, non-royalty revenue is recognized over the lesser of (1) the estimated period that the Company has historically enhanced and developed refinements to the specific technology, typically one to three years (the "upgrade period"), and (2) the remaining portion of the upgrade period after the date of delivery of all specified technology and documentation, provided that the fee is fixed or determinable and collection of the fee is reasonably assured. Royalties received during the upgrade period are recognized as revenue based on an amortization calculation of the elapsed portion of the upgrade period compared to the entire estimated upgrade period. Royalties received after the upgrade period has elapsed are recognized when reported to the Company, which generally coincides with the receipt of payment.
Product Warranty	Product Warranty The Company typically warrants its products against defects in materials and workmanship and non-conformance to specifications for 12 to 24 months. The majority of the Company's product warranty claims are settled through the return of the defective product and the shipment of replacement product. Warranty returns are included within the Company's allowance for returns, which is based on historical return rates. Actual future returns could differ from the allowance established. In addition, the Company accrues a liability for specific warranty costs expected to be settled other than through product return and replacement, if a loss is probable and can be reasonably estimated. Product warranty expenses during fiscal 2016 , 2015 , and 2014 were immaterial.
Advertising Cost	Advertising Costs The Company expenses all advertising costs as incurred. Advertising costs were immaterial for the fiscal years ended March 31, 2016 , 2015 and 2014 .
Research and Development	Research and Development Research and development costs are expensed as incurred. Assets purchased to support the Company's ongoing research and development activities are capitalized when related to products which have achieved technological feasibility or that have alternative future uses and are amortized over their estimated useful lives. Research and development expenses include expenditures for labor, share-based payments, depreciation, masks, prototype wafers, and expenses for development of process technologies, new packages, and software to support new products and design environments.
Foreign Currency Translation	Foreign Currency Translation The Company's foreign subsidiaries are considered to be extensions of the U.S. company and any translation gains and losses related to these subsidiaries are included in other income (expense) in the consolidated statements of income. As the U.S. dollar is utilized as the functional currency, gains and losses resulting from foreign currency transactions (transactions denominated in a currency other than the subsidiaries' functional currency) are also included in income. For a portion of fiscal 2015, certain foreign subsidiaries acquired as part of the Company's acquisition activities had the local currency as the functional currency. Once these entities were integrated into the Company's legal structure and intercompany agreements were executed, the U.S. dollar became the functional currency for such entities.
Income Taxes	Income Taxes The Company provides for income taxes in accordance with principles contained in ASC Topic 740, Income Taxes. Under these principles, the Company recognizes the amount of income tax payable or refundable for the current year and deferred tax assets and liabilities for the future tax consequences of events that have been recognized in its consolidated financial statements or tax returns. Deferred tax assets and liabilities are measured using enacted tax rates in effect for the year in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in earnings in the period when the new rate is enacted. Deferred tax assets are evaluated for future realization and reduced by a valuation allowance if it is more likely than not that a portion will not be realized. In assessing whether it is more likely than not that deferred tax assets will be realized, the Company considers all available evidence, both positive and negative, including its recent cumulative earnings experience and expectations of future available taxable income of the appropriate character by taxing jurisdiction, tax attribute carry back and carry forward periods available to them for tax reporting purposes, and prudent and feasible tax planning strategies. The Company measures and recognizes the amount of tax benefit that should be recorded for financial statement purposes for uncertain tax positions taken or expected to be taken in a tax return. With respect to uncertain tax positions, the Company evaluates the recognized tax benefits for de-recognition, classification, interest and penalties, interim period accounting and disclosure requirements. Judgment is required in assessing the future tax consequences of events that have been recognized in its consolidated financial statements or tax returns.
Cash and Cash Equivalents	Cash and Cash Equivalents All highly liquid investments, including marketable securities purchased with a remaining maturity of three months or less when acquired are considered to be cash equivalents.
Available-for-Sale Investments	Available-for-Sale Investments The Company classifies its investments in debt and marketable equity securities as available-for-sale based upon management's intent with regard to the investments and the nature of the underlying securities. The Company's available-for-sale investments consist of government agency bonds, municipal bonds, auction rate securities (ARS), corporate bonds and marketable equity securities. The Company's investments are carried at fair value with unrealized gains and losses reported in stockholders' equity unless losses are considered to be other than temporary impairments in which case the losses are recognized through the statement of income. Premiums and discounts are amortized or accreted over the life of the related available-for-sale security. Dividend and interest income are recognized when earned. The cost of available-for-sale debt securities sold is calculated using the first-in, first-out (FIFO) basis at the individual security level for sales from multiple lots. For sales of marketable equity securities, the Company uses an average cost basis at the individual security level. The Company includes within short-term investments its income yielding available-for-sale securities that can be readily converted to cash and includes within long-term investments those income yielding available-for-sale securities with maturities of over one year that have unrealized losses attributable to them or those that cannot be readily liquidated. Except as discussed in Note 4, the Company intends and has the ability to hold its long-term investments with temporary impairments until such time as these assets are no longer impaired. Such recovery of unrealized losses is not expected to occur within the next year.
Derivative Instruments	Derivative Instruments Derivative instruments are required to be recorded at fair value as either assets or liabilities in the Company's consolidated balance sheet. The Company's accounting policies for derivative instruments depends on whether the instrument has been designated and qualifies as part of a hedging relationship and further, on the type of hedging relationship. The Company does not apply hedge accounting to foreign currency forward contracts. Gains and losses associated with currency rate changes on forward contracts are recorded currently in income. These gains and losses have been immaterial to the Company's financial statements. Interest rate derivative instruments designated as fair value hedges are designed to manage the exposure to interest rate movements and to reduce borrowing costs by converting fixed-rate debt into floating-rate debt. Under these agreements, the Company agrees to exchange, at specified intervals, the difference between the fixed and floating interest amounts calculated by reference to an agreed-upon notional principal amount. For derivative instruments that are designated and qualify as fair value hedges, the gain or loss on the derivatives as well as the offsetting gain or loss on the hedged item attributable to the hedged risk are recognized in earnings. The Company evaluates hedge effectiveness at inception and on an ongoing basis. If a derivative is no longer expected to be highly effective, hedge accounting is discontinue
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts The Company maintains an allowance for doubtful accounts for estimated losses resulting from the inability of its customers to make required payments, which is included in bad debt expense. The Company determines the adequacy of this allowance by regularly reviewing the composition of its accounts receivable aging and evaluating individual customer receivables, considering such customer's financial condition, credit history and current economic conditions.
Inventories	Inventories Inventories are valued at the lower of cost or market using the first-in, first-out method. The Company writes down its inventory for estimated obsolescence or unmarketable inventory in an amount equal to the difference between the cost of inventory and the estimated market value based upon assumptions about future demand and market conditions. If actual market conditions are less favorable than those projected by the Company, additional inventory write-downs may be required. Inventory impairment charges establish a new cost basis for inventory and charges are not subsequently reversed to income even if circumstances later suggest that increased carrying amounts are recoverable. In estimating reserves for obsolescence, the Company primarily evaluates estimates of demand over a 12-month period and provides reserves for inventory on hand in excess of the estimated 12-month demand. Estimates for projected 12-month demand are generally based on the average shipments of the prior three-month period, which are then annualized to adjust for any potential seasonality in the Company's business. The estimated 12-month demand is compared to the Company's most recently developed sales forecast to further reconcile the 12-month demand estimate. Management reviews and adjusts the estimates as appropriate based on specific situations. For example, demand can be adjusted up for new products for which historic sales are not representative of future demand. Alternatively, demand can be adjusted down to the extent any existing products are being replaced or discontinued. In periods where the Company's production levels are substantially below normal operating capacity, unabsorbed overhead production costs associated with the reduced production levels of the Company's manufacturing facilities are charged directly to cost of sales.
Property, Plant and Equipment	Property, Plant and Equipment Property, plant and equipment are stated at cost. Major renewals and improvements are capitalized, while maintenance and repairs are expensed when incurred. The Company's property and equipment accounting policies incorporate estimates, assumptions and judgments relative to the useful lives of its property and equipment. Depreciation is provided for assets placed in service on a straight-line basis over the estimated useful lives of the relative assets, which range from 10 to 40 years for buildings and building improvements and 3 to 7 years for machinery and equipment. The Company evaluates the carrying value of its property and equipment when events or changes in circumstances indicate that the carrying value of such assets may be impaired. Asset impairment evaluations are, by nature, highly subjective.
Senior and Junior Subordinated Convertible Debentures	Senior and Junior Subordinated Convertible Debentures The Company separately accounts for the liability and equity components of its senior and junior subordinated convertible debentures in a manner that reflects its nonconvertible debt (unsecured debt) borrowing rate when interest cost is recognized. This results in a bifurcation of a component of the debt, classification of that component in equity and the accretion of the resulting discount on the debt to be recognized as part of interest expense in its consolidated statements of income. Lastly, the Company includes the dilutive effect of the shares of its common stock issuable upon conversion of the outstanding senior and junior subordinated convertible debentures in its diluted income per share calculation regardless of whether the market price triggers or other contingent conversion features have been met. The Company applies the treasury stock method as it has the intent and ability to settle the principal amounts of the senior and junior subordinated convertible debentures in cash. This method results in incremental dilutive shares when the average market value of the Company's common stock for a reporting period exceeds the conversion prices per share which were $66.05 and $24.31 for the senior and junior subordinated convertible debentures, respectively, at March 31, 2016 and adjust as dividends are recorded in the future. Upon a de-recognition event, the Company estimates the fair value of the liability component and compares that to the carrying amount in order to calculate the appropriate amount of gain or loss. The remaining amounts paid or issued (in the case of non cash consideration in the form of shares of common stock) are recognized as a reduction of additional paid-in-capital. The fair value of the liability component is estimated using the current comparable borrowing rate for an otherwise identical non-convertible debt instrument.
Litigation	Litigation The Company's estimated range of liability related to pending litigation is based on claims that management believes a loss is probable and for which an amount or range of loss is estimable.
Business Combinations	Business Combinations All of the Company's business combinations are accounted for at fair value under the acquisition method of accounting. Under the acquisition method of accounting, (i) acquisition-related costs, except for those costs incurred to issue debt or equity securities, will be expensed in the period incurred; (ii) non-controlling interests will be valued at fair value at the acquisition date; (iii) in-process research and development will be recorded at fair value as an intangible asset at the acquisition date and amortized once the technology reaches technological feasibility; (iv) restructuring costs associated with a business combination will be expensed subsequent to the acquisition date; and (v) changes in deferred tax asset valuation allowances and income tax uncertainties after the acquisition date will be recognized through income tax expense or directly in contributed capital. The measurement of fair value of assets acquired and liabilities assumed requires significant judgment. The valuation of intangible assets and acquired investments, in particular, requires that the Company use valuation techniques such as the income approach. The income approach includes the use of a discounted cash flow model, which includes discounted cash flow scenarios and requires the following significant estimates: revenue, expenses, capital spending and other costs, and discount rates based on the respective risks of the cash flows. The valuation of non-marketable equity investments acquired also takes into account variables such as conditions reflected in the capital markets, recent financing activity by the investees, the investees' capital structure and the terms of the investees' issued interests.
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets Goodwill is recorded when the purchase price paid for an acquisition exceeds the estimated fair value of the net identified tangible and intangible assets acquired. The Company is required to perform an impairment review annually, and more frequently under certain circumstances. The goodwill is subjected to this annual impairment test during the fourth quarter of the Company's fiscal year. The Company engages primarily in the development, manufacture and sale of semiconductor products as well as technology licensing. As a result, the Company concluded there are two reporting units, semiconductor products and technology licensing. Under the qualitative goodwill impairment assessment standard, management evaluates whether it is more likely than not that goodwill is impaired. If it is determined that it is more likely than not, the Company proceeds with the next step of the impairment test, which compares the fair value of the reporting unit to its carrying value. If the Company determines through the impairment process that goodwill has been impaired, the Company will record the impairment charge in its results of operation. Through March 31, 2016 , the Company has not had impaired goodwill. The Company's other intangible assets represent existing technologies, core and developed technology, in-process research and development, trademarks and trade names, and customer-related intangibles. Other intangible assets are amortized over their respective estimated lives, ranging from one year to ten years. In the event that facts and circumstances indicate intangibles or other long-lived assets may be impaired, the Company evaluates the recoverability and estimated useful lives of such assets. In-process research and development is capitalized until such time the related projects are completed or abandoned at which time the capitalized amounts will begin to be amortized or written off.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company assesses whether indicators of impairment of long-lived assets are present. If such indicators are present, the Company determines whether the sum of the estimated undiscounted cash flows attributable to the assets in question is less than their carrying value. If less, the Company recognizes an impairment loss based on the excess of the carrying amount of the assets over their respective fair values. Fair value is determined by discounted future cash flows, appraisals or other methods. If the assets determined to be impaired are to be held and used, the Company recognizes an impairment loss through a charge to operating results to the extent the present value of anticipated net cash flows attributable to the asset are less than the asset's carrying value. The Company would depreciate the remaining value over the remaining estimated useful life of the asset.
Share-Based Compensation	Share-Based Compensation The Company has equity incentive plans under which non-qualified stock options and restricted stock units (RSUs) have been granted to employees and non-employee members of the Board of Directors. In the second half of fiscal 2006, the Company adopted RSUs as its primary equity incentive compensation instrument for employees. The Company also has employee stock purchase plans for eligible employees. The Company estimates the fair value of share-based payment awards on the date of grant using an option pricing model. The value of the portion of the award that is ultimately expected to vest is recognized as expense straight-line over the requisite service periods. The Company has estimated the fair value of each award as of the date of grant using the Black-Scholes option pricing model, which was developed for use in estimating the value of traded options that have no vesting restrictions and that are freely transferable. Determining the appropriate fair-value model and calculating the fair value of share-based awards at the date of grant requires judgment. The fair value of RSUs is based on the fair market value of the Company's common stock on the date of grant discounted for expected future dividends. The Company uses the Black-Scholes option pricing model to estimate the fair value of employee stock options and rights to purchase shares under stock purchase plans. Option pricing models, including the Black-Scholes model, also require the use of input assumptions, including expected volatility, expected life, expected dividend rate, and expected risk-free rate of return. The Company uses a blend of historical and implied volatility based on options freely traded in the open market as it believes this is more reflective of market conditions and a better indicator of expected volatility than using purely historical volatility. The expected life of the awards is based on historical and other economic data trended into the future. The risk-free interest rate assumption is based on observed interest rates appropriate for the expected terms of the Company's awards. The dividend yield assumption is based on the Company's history and expectation of future dividend payouts. The Company estimates the number of share-based awards which will be forfeited due to employee turnover. Quarterly changes in the estimated forfeiture rate would affect share-based compensation, as the impact on prior period amortization for all unvested awards is recognized in the period the forfeiture estimate is changed. If the actual forfeiture rate is higher than the estimated forfeiture rate, then an adjustment is made to increase the estimated forfeiture rate, which will result in a decrease to the expense recognized in the financial statements. If the actual forfeiture rate is lower than the estimated forfeiture rate, then an adjustment is made to decrease the estimated forfeiture rate, which will result in an increase to the expense recognized in the financial statements. If forfeiture adjustments are made, they would affect the Company's results of operations. The effect of forfeiture adjustments in the years ended March 31, 2016 , 2015 and 2014 was immaterial. The Company evaluates the assumptions used to value its awards on a quarterly basis. If factors change and the Company employs different assumptions, share-based compensation expense may differ significantly from what was recorded in the past. If there are any modifications or cancellations of the underlying unvested securities, the Company may be required to accelerate or increase any remaining unearned share-based compensation expense. Future share-based compensation expense and unearned share-based compensation will increase to the extent that the Company grants additional equity awards to employees or it assumes unvested equity awards in connection with acquisitions.
Concentration of Credit Risk	Concentrations of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of investments in debt securities and trade receivables. Investments in debt securities with original maturities of greater than six months consist primarily of AAA and AA rated financial instruments and counterparties. The Company's investments are primarily in direct obligations of the U.S. government or its agencies, corporate bonds, and municipal bonds. Concentrations of credit risk with respect to accounts receivable are generally not significant due to the diversity of the Company's customers and geographic sales areas. The Company sells its products primarily to OEMs and distributors in the Americas, Europe and Asia. The Company performs ongoing credit evaluations of its customers' financial condition and, as deemed necessary, may require collateral, primarily letters of credit. Distributor advances, included in deferred income on shipments to distributors in the consolidated balance sheets, totaled $ 102.9 million at March 31, 2016 and $ 116.0 million at March 31, 2015 . On sales to distributors, the Company's payment terms generally require the distributor to settle amounts owed to the Company for an amount in excess of their ultimate cost. The Company's sales price to its distributors may be higher than the amount that the distributors will ultimately owe the Company because distributors often negotiate price reductions after purchasing the product from the Company and such reductions are often significant. It is the Company's practice to apply these negotiated price discounts to future purchases, requiring the distributor to settle receivable balances, on a current basis, generally within 30 days, for amounts originally invoiced. This practice has an adverse impact on the working capital of the Company's distributors. As such, the Company has entered into agreements with certain distributors whereby it advances cash to the distributors to reduce the distributor's working capital requirements. These advances are reconciled at least on a quarterly basis and are estimated based on the amount of ending inventory as reported by the distributor multiplied by a negotiated percentage. Such advances have no impact on revenue recognition or the Company's consolidated statements of income. The Company processes discounts taken by distributors against its deferred income on shipments to distributors' balance and trues-up the advanced amounts generally after the end of each completed fiscal quarter. The terms of these advances are set forth in binding legal agreements and are unsecured, bear no interest on unsettled balances and are due upon demand. The agreements governing these advances can be canceled by the Company at any time.
Use of Estimates	Use of Estimates The Company has made a number of estimates and assumptions relating to the reporting of assets, liabilities, revenues and expenses and the disclosure of contingent assets and liabilities to prepare its consolidated financial statements in conformity with U.S. Generally Accepted Accounting Principles. Actual results could differ from those estimates.
Business Segments	Business Segments Operating segments are components of an enterprise about which separate financial information is regularly reviewed by the chief operating decision maker(s) ("CODM") to assess the performance of the component and make decisions about the resources to be allocated to the component. The Company's Chairman and Chief Executive Officer and the Company's President and Chief Operating Officer have been identified as the CODMs as they jointly manage the Company's worldwide consolidated enterprise. Based on the Company's structure and manner in which the Company is managed and decisions are made, the Company's business is made up of two operating segments, semiconductor products and technology licensing. In the semiconductor products segment, the Company designs, develops, manufactures and markets microcontrollers, development tools and analog, interface, mixed signal and timing products. Under the leadership of the CODMs, the Company is structured and organized around standardized roles and responsibilities based on product groups and functional activities. The Company's product groups are responsible for product research, design and development. The Company's functional activities include sales, marketing, manufacturing, information technology, human resources, legal and finance. The Company's product groups have similar products, production processes, types of customers and methods for distribution. In addition, the tools and technologies used in the design and manufacture of the Company's products are shared among the various product groups. The Company's product group leaders, under the direction of the CODMs, define the product roadmaps and team with sales personnel to achieve design wins and revenue and other performance targets. Product group leaders also interact with manufacturing and operational personnel who are responsible for the production, prioritization and planning of the Company's manufacturing capabilities to help ensure the efficiency of the Company's operations and fulfillment of customer requirements. This centralized structure supports a global operating strategy in which the CODMs assess performance and allocate resources based on the Company's consolidated results.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements In May 2014, the FASB issued ASU 2014-09 -Revenue from Contracts with Customers (Topic 606) , which will supersede nearly all existing revenue recognition guidance under US GAAP. The standard's core principle is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. In July 2015, the FASB delayed the effective date of the new standard by one year to December 15, 2017, for annual and interim reporting periods beginning after that date. In accordance with the delay, the new standard will be effective for the Company beginning no later than April 1, 2018. Early adoption is permitted, but not before the original effective date of December 15, 2016. The new standard allows for the amendment to be applied either retrospectively to each prior reporting period presented or retrospectively as a cumulative-effect adjustment as of the date of adoption. In March 2016, the FASB issued ASU 2016-08 - Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net) , which clarifies the implementation guidance on principal versus agent considerations. In April 2016, the FASB issued ASU 2016-10 - Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing , which clarifies the implementation guidance on identifying performance obligations. In May 2016, the FASB issued ASU 2016-12 - Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients , which addresses implementation issues that were raised by stakeholders and discussed by the Revenue Recognition Transition Resource Group. As described in the Company's significant accounting policies, the Company defers the revenue and cost of sales on shipments to distributors until the distributor sells the product to their end customer. Upon adoption of ASU 2014-09, ASU 2015-14, ASU 2016-08, ASU 2016-10 and ASU 2016-12, the Company will no longer defer revenue until sale by the distributor to the end customer, but rather, will be required to estimate the effects of returns and allowances provided to distributors and record revenue at the time of sale to the distributor. The Company is currently evaluating the impact that the adoption of the standards may have on its consolidated financial statements and additional changes may be identified. The Company has not elected a transition method. In April 2015, the FASB issued ASU 2015-03- Simplifying the Presentation of Debt Issuance Costs. This standard amends existing guidance to require the presentation of debt issuance costs in the balance sheet as a deduction from the carrying amount of the related debt liability instead of as a deferred charge. ASU 2015-03 is effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2015 and requires retrospective application. The Company does not expect this standard to have a material impact on its consolidated financial statements. In July 2015, the FASB issued ASU 2015-11- Simplifying the Measurement of Inventory. This standard requires that entities measure inventory at the lower of cost and net realizable value. Net realizable value is the estimated selling price in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. ASU 2015-11 is effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2016 and is applied prospectively. Early adoption is permitted. The Company does not expect this standard to have a material impact on its consolidated financial statements. In September 2015, the FASB issued ASU 2015-16- Business Combinations (Topic 805), Simplifying the Accounting for Measurement-Period Adjustments . This standard amends existing guidance to require acquiring entities in a business combination to recognize measurement-period adjustments in the reporting period in which the adjustment amounts are determined. The standard also requires entities to present separately on the face of the income statement (or disclose in the notes to the financial statements) the amount of the adjustment reflected in the current period earnings, by line item, that would have been recognized in previous reporting periods if the adjustment to the provisional amounts had been recognized as of the acquisition date. ASU 2015-16 is effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2015. Early adoption is permitted. The standard is to be applied prospectively to measurement-period adjustments that occur after the effective date. The Company adopted this standard beginning in the second quarter of fiscal 2016 and the adoption of this standard did not have a material impact on its consolidated financial statements. In November 2015, the FASB issued ASU 2015-17- Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes. The new guidance requires that all deferred tax assets and liabilities, along with any related valuation allowance, be classified as noncurrent on the balance sheet. The guidance is effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2016, with early adoption permitted. The new guidance was adopted by the Company on a prospective basis in the third quarter for the fiscal year ended March 31, 2016. Prior period amounts in the Company's consolidated balance sheet within this Annual Report on Form 10-K were not adjusted to conform to the new accounting standard. The adoption of this accounting standard was not material to the Company's consolidated financial statements. In January 2016, the FASB issued ASU 2016-01- Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities . This standard addresses certain aspects of recognition, measurement, presentation, and disclosure of financial instruments. ASU 2016-01 is effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2017. Early adoption is not permitted. The Company is currently evaluating the impact the adoption of this standard will have on its consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases . This standard requires lessees to recognize a lease liability and a right-of-use asset on the balance sheet and aligns many of the underlying principles of the new lessor model with those in Accounting Standards Codification Topic 606, Revenue from Contracts with Customers. ASU 2016-02 is effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2018. The Company is currently evaluating the impact the adoption of this standard will have on its consolidated financial statements. In March 2016, the FASB issued ASU 2016-09, Compensation - Stock Compensation, Improvements to Employee Share-Based payment Accounting (Topic 718). This standard is intended to provide simplification of the accounting for share-based payment transactions, including the accounting for income taxes, forfeitures, and statutory tax withholding requirements, as well as classification in the statement of cash flows. ASU 2016-09 is effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2016. The Company is currently evaluating the impact the adoption of this standard will have on its consolidated financial statements.

Business Acquisitions (Tables)

Business Acquisitions (Tables)	12 Months Ended
	Mar. 31, 2016
Micrel Incorporated [Member]
Business Acquisition [Line Items]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The table below represents the preliminary allocation of the purchase price, including adjustments to the purchase price allocation from the originally reported figures at September 30, 2015, to the net assets acquired based on their estimated fair values as of August 3, 2015, as well as the associated estimated useful lives of the acquired intangible assets at that date (amounts in thousands): Assets acquired Previously Reported September 30, 2015 Adjustments March 31, 2016 Cash and cash equivalents $ 99,196 $ — $ 99,196 Accounts receivable, net 12,296 1,800 14,096 Inventories 78,967 (5,499 ) 73,468 Prepaid expenses and other current assets 10,548 104 10,652 Property, plant and equipment, net 38,566 — 38,566 Goodwill 437,060 3,932 440,992 Purchased intangible assets 274,800 (1,300 ) 273,500 Other assets 4,268 — 4,268 Total assets acquired 955,701 (963 ) 954,738 Liabilities assumed Accounts payable (11,068 ) — (11,068 ) Other current liabilities (30,241 ) (1,400 ) (31,641 ) Deferred tax liabilities (88,796 ) 761 (88,035 ) Long-term income tax payable (9,239 ) 1,602 (7,637 ) Other long-term liabilities (127 ) — (127 ) Total liabilities assumed (139,471 ) 963 (138,508 ) Purchase price allocated $ 816,230 $ — $ 816,230
Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination	Purchased Intangible Assets Useful Life August 3, 2015 (in years) (in thousands) Core/developed technology 10 $ 175,800 In-process technology 10 21,000 Customer-related 5 71,100 Backlog 1 5,600 Total purchased intangible assets $ 273,500
Business Acquisition, Pro Forma Information	The following unaudited pro-forma consolidated results of operations for the years ended March 31, 2016 and 2015 assume the Micrel acquisition occurred as of April 1, 2014. The pro-forma adjustments are mainly comprised of acquired inventory fair value costs and amortization of purchased intangible assets. The pro-forma results of operations are presented for informational purposes only and are not indicative of the results of operations that would have been achieved if the acquisition had taken place on April 1, 2014 or of results that may occur in the future (amounts in thousands except per share data): Year ended March 31, 2016 2015 Net sales $ 2,283,517 $ 2,352,727 Net income $ 365,654 $ 278,673 Basic earnings per share $ 1.80 $ 1.39 Diluted earnings per share $ 1.68 $ 1.25
ISSC Technologies Corporation [Member]
Business Acquisition [Line Items]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The table below represents the allocation of the purchase price to the net assets acquired based on their estimated fair values as of July 17, 2014 as well as the associated estimated useful lives of the acquired intangible assets at that date. The purchase price allocation was finalized as of June 30, 2015 (amounts in thousands): Assets acquired June 30, 2015 Cash and cash equivalents $ 15,120 Short-term investments 27,063 Accounts receivable, net 8,792 Inventories 16,542 Prepaid expenses and other current assets 2,501 Property, plant and equipment, net 2,637 Goodwill 154,788 Purchased intangible assets (1) 147,800 Other assets 1,370 Total assets acquired 376,613 Liabilities assumed Accounts payable (9,860 ) Other current liabilities (16,535 ) Long-term income tax payable (4,791 ) Deferred tax liability (25,126 ) Other long-term liabilities (245 ) Total liabilities assumed (56,557 ) Net assets acquired including noncontrolling interest 320,056 Less: noncontrolling interest (52,467 ) Net assets acquired $ 267,589
Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination	(1) Purchased Intangible Assets Useful Life July 17, 2014 (in years) (in thousands) Core/developed technology 10 $ 68,900 In-process technology 10 27,200 Customer-related 3 51,100 Backlog 1 600 $ 147,800
Supertex Inc. [Member]
Business Acquisition [Line Items]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The table below represents the allocation of the purchase price to the net assets acquired based on their estimated fair values as of April 1, 2014 as well as the associated estimated useful lives of the acquired intangible assets at that date. The purchase price allocation was finalized on March 31, 2015 (amounts in thousands): Assets acquired March 31, 2015 Cash and cash equivalents $ 14,790 Short-term investments 140,984 Accounts receivable, net 7,047 Inventories 27,630 Prepaid expenses 1,493 Deferred tax assets 2,456 Other current assets 12,625 Property, plant and equipment, net 15,679 Goodwill 143,160 Purchased intangible assets (1) 89,600 Other assets 325 Total assets acquired 455,789 Liabilities assumed Accounts payable (8,481 ) Accrued liabilities (19,224 ) Long-term income tax payable (3,796 ) Deferred tax liability (32,511 ) Total liabilities assumed (64,012 ) Net assets acquired $ 391,777
Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination	(1) Purchased Intangible Assets Useful Life April 1, 2014 (in years) (in thousands) Core/developed technology 10 $ 68,900 In-process technology 10 1,900 Customer-related 2 17,700 Backlog 1 1,100 $ 89,600

Investments (Tables)

Investments (Tables)	12 Months Ended
	Mar. 31, 2016
Investments [Abstract]
Summary of available-for-sale securities	The following is a summary of available-for-sale securities at March 31, 2016 (amounts in thousands): Available-for-sale Securities Adjusted Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Government agency bonds $ 468,290 $ 439 $ (99 ) $ 468,630 Corporate bonds and debt 1,000 — — 1,000 Marketable equity securities 2,195 8 — 2,203 Total $ 471,485 $ 447 $ (99 ) $ 471,833 The following is a summary of available-for-sale securities at March 31, 2015 (amounts in thousands): Available-for-sale Securities Adjusted Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Government agency bonds $ 741,780 $ 676 $ (200 ) $ 742,256 Municipal bonds 41,552 155 (9 ) 41,698 Auction rate securities 9,825 — — 9,825 Time deposits (1) 506 — — 506 Corporate bonds and debt 924,818 2,376 (265 ) 926,929 Marketable equity securities 1,362 11,804 — 13,166 Total $ 1,719,843 $ 15,011 $ (474 ) $ 1,734,380
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Table Text Block]	The following tables show all investments in an unrealized loss position for which an other-than-temporary impairment has not been recognized and the related gross unrealized losses and fair value, aggregated by investment category and length of time that the individual securities have been in a continuous unrealized loss position (amounts in thousands): March 31, 2016 Less than 12 Months 12 Months or Greater Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss Government agency bonds $ 148,562 $ (99 ) $ — $ — $ 148,562 $ (99 ) Corporate bonds and debt — — 1,000 — 1,000 — Total $ 148,562 $ (99 ) $ 1,000 $ — $ 149,562 $ (99 ) March 31, 2015 Less than 12 Months 12 Months or Greater Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss Government agency bonds $ 162,948 $ (142 ) $ 29,942 $ (58 ) $ 192,890 $ (200 ) Municipal bonds 13,318 (9 ) — — 13,318 (9 ) Corporate bonds and debt 163,095 (219 ) 19,021 (46 ) 182,116 (265 ) Total $ 339,361 $ (370 ) $ 48,963 $ (104 ) $ 388,324 $ (474 )
Summary of amortized cost and estimated fair value of available-for-sale securities, by maturity	The amortized cost and estimated fair value of the available-for-sale securities at March 31, 2016 , by contractual maturity, excluding marketable equity securities of $2.2 million , which have no contractual maturity, are shown below (amounts in thousands). Expected maturities can differ from contractual maturities because the issuers of the securities may have the right to prepay obligations without prepayment penalties, and the Company views its available-for-sale securities as available for current operations. Adjusted Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Available-for-sale Due in one year or less $ 41,078 $ 5 $ (5 ) $ 41,078 Due after one year and through five years 428,212 434 (94 ) 428,552 Due after five years and through ten years — — — — Due after ten years — — — — Total $ 469,290 $ 439 $ (99 ) $ 469,630 The amortized cost and estimated fair value of the available-for-sale securities at March 31, 2015 , by maturity, excluding marketable equity securities of $ 13.2 million and corporate debt of $ 6.2 million , which have no contractual maturity, are shown below (amounts in thousands). Adjusted Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Available-for-sale Due in one year or less $ 224,531 $ 512 $ (34 ) $ 225,009 Due after one year and through five years 1,395,685 2,648 (330 ) 1,398,003 Due after five years and through ten years 82,250 47 (110 ) 82,187 Due after ten years 9,825 — — 9,825 Total $ 1,712,291 $ 3,207 $ (474 ) $ 1,715,024

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Mar. 31, 2016
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]	Assets measured at fair value on a recurring basis at March 31, 2016 are as follows (amounts in thousands): Quoted Prices in Active Markets for Identical Instruments (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Balance Assets Cash and cash equivalents: Money market mutual funds $ 1,787,446 $ — $ — $ 1,787,446 Deposit accounts — 305,305 — 305,305 Short-term investments: Marketable equity securities 2,203 — — 2,203 Corporate bonds and debt — 1,000 — 1,000 Government agency bonds — 350,081 — 350,081 Long-term investments: Government agency bonds — 118,549 — 118,549 Total assets measured at fair value $ 1,789,649 $ 774,935 $ — $ 2,564,584 Assets measured at fair value on a recurring basis at March 31, 2015 are as follows (amounts in thousands): Quoted Prices in Active Markets for Identical Instruments (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Balance Assets Cash and cash equivalents: Money market mutual funds $ 279,833 $ — $ — $ 279,833 Deposit accounts — 327,982 — 327,982 Short-term investments: Marketable equity securities 13,166 — — 13,166 Corporate bonds and debt — 756,664 — 756,664 Time deposits (1) — 506 — 506 Government agency bonds — 549,737 — 549,737 Municipal bonds — 30,981 — 30,981 Long-term investments: Corporate bonds and debt — 164,075 6,190 170,265 Government agency bonds — 192,519 — 192,519 Municipal bonds — 10,717 — 10,717 Auction rate securities — — 9,825 9,825 Other assets Derivative assets — 8,928 — 8,928 Total assets measured at fair value $ 292,999 $ 2,042,109 $ 16,015 $ 2,351,123
Fair Value, Assets and Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]	The following table presents a reconciliation for all assets measured at fair value on a recurring basis, excluding accrued interest components, using significant unobservable inputs (Level 3) for the year ended March 31, 2016 . There were no changes in the fair value of these assets measured on a recurring basis during fiscal 2015 (amounts in thousands): Year ended March 31, 2016 Auction Rate Securities Corporate Debt Total Gains (Losses) Balance at March 31, 2015 $ 9,825 $ 6,190 $ — Total gains (losses) (realized): Included in earnings 2,780 (3,995 ) (1,215 ) Purchases, sales, issuances, and settlements, net (12,605 ) — — Transfers out of Level 3 — (2,195 ) — Balance at March 31, 2016 $ — $ — $ (1,215 )

NOTE 6 FAIR VALUE OF FINANCIAL

NOTE 6 FAIR VALUE OF FINANCIAL INSTRUMENTS Fair Value of Financial Instruments (Tables)	12 Months Ended
	Mar. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value, by Balance Sheet Grouping [Table Text Block]	The carrying amounts and fair values of the Company’s senior and junior subordinated convertible debentures as of March 31, 2016 and 2015 are as follows (amounts in thousands): March 31, 2016 March 31, 2015 Carrying Amount Fair Value Carrying Amount Fair Value 1.625% Senior Subordinated Convertible Debentures $ 1,234,733 $ 1,762,088 $ 1,174,036 $ 1,787,531 2.125% Junior Subordinated Convertible Debentures $ 196,304 $ 1,143,117 $ 190,870 $ 1,124,125

Accounts Receivable (Tables)

Accounts Receivable (Tables)	12 Months Ended
	Mar. 31, 2016
Accounts Receivable, Net [Abstract]
Accounts Receivable Schedule	Accounts receivable consists of the following (amounts in thousands): March 31, 2016 March 31, 2015 Trade accounts receivable $ 289,013 $ 269,844 Other 3,710 6,714 Total accounts receivable, gross 292,723 276,558 Less allowance for doubtful accounts 2,540 2,621 Total accounts receivable, net $ 290,183 $ 273,937

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Mar. 31, 2016
Inventory Disclosure [Abstract]
Components of inventories	The components of inventories consist of the following (amounts in thousands): March 31, 2016 March 31, 2015 Raw materials $ 12,179 $ 13,263 Work in process 208,283 197,565 Finished goods 86,353 68,628 Total inventories $ 306,815 $ 279,456

Property, Plant and Equipment45

Property, Plant and Equipment (Tables)	12 Months Ended
	Mar. 31, 2016
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Property, plant and equipment consists of the following (amounts in thousands): March 31, 2016 March 31, 2015 Land $ 63,907 $ 55,624 Building and building improvements 458,379 434,403 Machinery and equipment 1,645,617 1,576,074 Projects in process 99,370 76,315 Total property, plant and equipment, gross 2,267,273 2,142,416 Less accumulated depreciation and amortization 1,657,877 1,560,844 Total property, plant and equipment, net $ 609,396 $ 581,572

Noncontrolling interests (Table

Noncontrolling interests (Tables)	12 Months Ended
	Mar. 31, 2016
Noncontrolling Interest [Abstract]
Noncontrolling Interest Disclosure [Table Text Block]	The following table presents the changes in the components of noncontrolling interests for the years ended March 31, 2016 and March 31, 2015 (amounts in thousands): Noncontrolling Interests Balance at March 31, 2014 $ — Additions due to acquisition of controlling interest in ISSC 52,467 Net loss attributable to noncontrolling interests (3,684 ) Other comprehensive loss attributable to noncontrolling interests (866 ) Purchase of additional interests (31,849 ) Other 304 Balance at March 31, 2015 16,372 Net loss attributable to noncontrolling interests (207 ) Purchase of additional interests (16,165 ) Balance at March 31, 2016 $ —
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Table Text Block]	The following table presents the effect of changes in the Company's ownership interest in ISSC on the Company's stockholders' equity (amounts in thousands): Year ended March 31, 2016 2015 Net income attributable to Microchip Technology stockholders $ 324,132 $ 369,009 (Decrease) increase in paid-in capital for purchase of additional interests (1,611 ) 345 Increase in paid-in capital for converted stock options — 1,094 Net transfers (to) from noncontrolling interest (1,611 ) 1,439 Change from net income attributable to Microchip Technology stockholders and transfers (to) from noncontrolling interest $ 322,521 $ 370,448

Intangible Assets and Goodwil47

Intangible Assets and Goodwill (Tables)	12 Months Ended
	Mar. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	Intangible assets consist of the following (amounts in thousands): March 31, 2016 Gross Amount Accumulated Amortization Net Amount Core and developed technology $ 724,883 $ (255,460 ) $ 469,423 Customer-related 278,542 (200,331 ) 78,211 Trademarks and trade names 11,700 (7,571 ) 4,129 In-process technology 54,308 — 54,308 Distribution rights 5,580 (5,302 ) 278 Total $ 1,075,013 $ (468,664 ) $ 606,349 March 31, 2015 Gross Amount Accumulated Amortization Net Amount Core and developed technology $ 549,415 $ (189,149 ) $ 360,266 Customer-related 262,769 (192,283 ) 70,486 Trademarks and trade names 13,180 (6,979 ) 6,201 In-process technology 67,142 — 67,142 Distribution rights 5,580 (5,258 ) 322 Total $ 898,086 $ (393,669 ) $ 504,417
Projected Amortization Expense	The following is an expected amortization schedule for the intangible assets for fiscal 2017 through fiscal 2021 , absent any future acquisitions or impairment charges (amounts in thousands): Year ending March 31, Projected Amortization Expense 2017 $137,321 2018 110,811 2019 94,573 2020 76,683 2021 50,974
Goodwill Activity	Goodwill activity for fiscal years 2016 and 2015 was as follows (amounts in thousands): Semiconductor Products Reporting Unit Technology Licensing Reporting Unit Balance at March 31, 2014 $ 256,897 $ 19,200 Additions due to the acquisition of Supertex 143,160 — Additions due to acquisition of controlling interest in ISSC 154,399 — Adjustments due to other acquisitions 624 — Foreign currency translation adjustments (3,009 ) — Balance at March 31, 2015 552,071 19,200 Additions due to the acquisition of Micrel 440,992 — Adjustments due to the acquisition of ISSC 389 — Balance at March 31, 2016 $ 993,452 $ 19,200

Income taxes (Tables)

Income taxes (Tables)	12 Months Ended
	Mar. 31, 2016
Income Tax Disclosure [Abstract]
Components of income tax expense (benefit)	The income tax provision consists of the following (amounts in thousands): Year Ended March 31, 2016 2015 2014 Pretax Income: U.S. $ (75,515 ) $ (944 ) $ 28,245 Foreign 356,808 346,851 404,109 $ 281,293 $ 345,907 $ 432,354 Current expense (benefit): U.S. Federal $ (3,966 ) $ (3,185 ) $ 992 State (188 ) (24 ) 64 Foreign 21,947 16,602 30,697 Total current $ 17,793 $ 13,393 $ 31,753 Deferred expense (benefit): U.S. Federal $ (42,207 ) $ (22,641 ) $ 14,445 State (1,990 ) (1,562 ) 929 Foreign (16,228 ) (8,608 ) (10,054 ) Total deferred (60,425 ) (32,811 ) 5,320 Total $ (42,632 ) $ (19,418 ) $ 37,073
Reconciliation of expected federal income tax expense to actual	The sources and tax effects of the differences in the total income tax provision are as follows (amounts in thousands): Year Ended March 31, 2016 2015 2014 Computed expected income tax provision $ 98,453 $ 121,067 $ 151,324 State income taxes, net of federal benefits (1,246 ) (20 ) 686 Research and development tax credits - current year (13,542 ) (9,703 ) (4,875 ) Research and development tax credits - prior years (2,511 ) (1,789 ) 1,600 Foreign income taxed at lower than the federal rate (114,497 ) (106,939 ) (116,003 ) Increases related to current and prior year tax positions 14,462 19,769 16,809 Decreases related to prior year tax positions (1) (12,103 ) (33,100 ) (14,581 ) Withholding taxes 5,970 5,218 6,212 Change in valuation allowance (2,482 ) (14,286 ) — Intercompany prepaid tax asset amortization (15,493 ) (1,089 ) — Other 357 1,454 (4,099 ) Total $ (42,632 ) $ (19,418 ) $ 37,073 (1) The release of prior year tax positions during fiscal 2016 increased each of the basic and diluted net income per common share by $0.06 . The release of prior year tax positions during fiscal 2015 increased the basic and diluted net income per common share by $0.16 and $0.15 , respectively. The release of prior year tax positions during fiscal 2014 increased each of the basic and diluted net income per common share by $0.07 .
Schedule of deferred tax assets and liabilities	The tax effects of temporary differences that give rise to significant portions of the Company's deferred tax assets and deferred tax liabilities are as follows (amounts in thousands): March 31, 2016 2015 Deferred tax assets: Deferred intercompany profit $ 12,642 $ 10,865 Deferred income on shipments to distributors 34,830 34,493 Inventory valuation 12,082 9,605 Net operating loss carryforward 63,209 105,756 Capital loss carryforward 5,707 4,582 Share-based compensation 31,410 26,780 Income tax credits 100,294 115,893 Property, plant and equipment, principally due to differences in depreciation 16,262 2,236 Accrued expenses and other 7,559 671 Gross deferred tax assets 283,995 310,881 Valuation allowances (161,834 ) (116,482 ) Deferred tax assets, net of valuation allowances 122,161 194,399 Deferred tax liabilities: Convertible debentures (496,626 ) (493,897 ) Other (9,922 ) (10,649 ) Deferred tax liabilities (506,548 ) (504,546 ) Net deferred tax liability $ (384,387 ) $ (310,147 ) Reported as: Current deferred tax assets $ — $ 71,045 Non-current deferred tax assets 14,831 — Non-current deferred tax liability (399,218 ) (381,192 ) Net deferred tax liability $ (384,387 ) $ (310,147 )
Rollforward of unrecognized tax benefits	The following table summarizes the activity related to the Company's gross unrecognized tax benefits from April 1, 2013 to March 31, 2016 (amounts in thousands): Year Ended March 31, 2016 2015 2014 Beginning balance $ 170,654 $ 149,878 $ 152,845 Increases related to acquisitions 46,245 8,381 341 Decreases related to settlements with tax authorities (7,954 ) (20,197 ) (15,016 ) Decreases related to statute of limitation expirations (4,591 ) (9,031 ) (4,069 ) Increases related to current year tax positions 16,315 23,179 14,669 Increases related to prior year tax positions — 18,444 1,108 Ending balance $ 220,669 $ 170,654 $ 149,878

Equity Incentive Plans (Tables)

Equity Incentive Plans (Tables)	12 Months Ended
	Mar. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-based compensation expense	The following table presents the details of the Company's share-based compensation expense (amounts in thousands): Year Ended March 31, 2016 2015 2014 Cost of sales $ 8,252 (1) $ 9,010 (1) $ 7,340 (1) Research and development 32,022 28,164 24,554 Selling, general and administrative 31,146 21,422 21,893 Pre-tax effect of share-based compensation 71,420 58,596 53,787 Income tax benefit 23,012 10,640 5,722 Net income effect of share-based compensation $ 48,408 $ 47,956 $ 48,065
Schedule of Share-based Compensation, Restricted Stock Units Award Activity	RSU share activity under the 2004 Plan is set forth below: Number of Shares Nonvested shares at April 1, 2013 6,009,831 Granted 1,616,632 Forfeited/expired (282,964 ) Vested (1,813,465 ) Nonvested shares at March 31, 2014 5,530,034 Granted 1,446,968 Forfeited/expired (266,415 ) Vested (1,441,671 ) Nonvested shares at March 31, 2015 5,268,916 Granted 2,479,729 Assumed upon acquisition 525,442 Forfeited/expired (360,072 ) Vested (1,606,273 ) Nonvested shares at March 31, 2016 6,307,742
Schedule of Share-based Compensation, Stock Options, Activity	Stock option and stock appreciation right (SAR) activity under the Company's stock incentive plans in the three years ended March 31, 2016 is set forth below: Number of Shares Weighted Average Exercise Price per Share Outstanding at April 1, 2013 2,269,803 $ 25.58 Granted — — Exercised (1,675,663 ) 25.91 Canceled (20,529 ) 22.78 Outstanding at March 31, 2014 573,611 24.75 Granted 27,654 46.66 Assumed upon acquisition 666,586 29.33 Exercised (477,618 ) 26.42 Canceled (105,934 ) 28.17 Outstanding at March 31, 2015 684,299 28.41 Granted 244 41.09 Assumed upon acquisition 604,900 35.03 Exercised (221,987 ) 25.30 Canceled (153,948 ) 31.52 Outstanding at March 31, 2016 913,508 $ 33.00
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	The weighted average fair values per share of stock options granted in the years ended March 31, 2016 and 2015 was $ 8.85 and $ 9.00 , respectively. The fair values per share of stock options granted in the years ended March 31, 2016 and 2015 were estimated utilizing the following assumptions: Year Ended March 31, 2016 2015 Expected term (in years) 6.5 6.5 Volatility 29.50 % 26.65 % Risk-free interest rate 1.54 % 1.59 % Dividend yield 3.00 % 3.00 %

Commitments (Tables)

Commitments (Tables)	12 Months Ended
	Mar. 31, 2016
Commitments [Abstract]
Future minimum lease commitments	The future minimum lease commitments under these operating leases at March 31, 2016 were as follows (amounts in thousands): Year Ending March 31, Amount 2017 $ 16,370 2018 12,350 2019 7,677 2020 3,098 2021 1,000 Thereafter 667 Total minimum payments $ 41,162

Geographic and Segment Inform51

Geographic and Segment Information (Tables)	12 Months Ended
	Mar. 31, 2016
Segment Reporting [Abstract]
Revenues and gross profit for each segment	The following table represents revenues and gross profit for each segment (amounts in thousands): Years ended March 31, 2016 2015 2014 Net Sales Gross Profit Net Sales Gross Profit Net Sales Gross Profit Semiconductor products $ 2,084,210 $ 1,116,340 $ 2,057,443 $ 1,139,971 $ 1,836,639 $ 1,034,165 Technology licensing 89,124 89,124 89,593 89,593 94,578 94,578 Total $ 2,173,334 $ 1,205,464 $ 2,147,036 $ 1,229,564 $ 1,931,217 $ 1,128,743
Schedule of Disclosure on Geographic Areas, Long-Lived Assets in Individual Foreign Countries by Country	Identifiable long-lived assets (consisting of property, plant and equipment net of accumulated amortization) by geographic area are as follows (amounts in thousands): March 31, 2016 2015 United States $ 373,860 $ 331,372 Thailand 182,813 197,981 Various other countries 52,723 52,219 Total long-lived assets $ 609,396 $ 581,572

Derivative Instruments (Tables)

Derivative Instruments (Tables)	12 Months Ended
	Mar. 31, 2016
Derivatives, Fair Value [Line Items]
Schedule of Fair Value Hedging Instruments, Statements of Financial Performance and Financial Position, Location [Table Text Block]	The following table summarizes the location and fair value amounts of derivative instruments reported in the consolidated balance sheets at March 31, 2015 (amounts in thousands): Asset Derivatives Derivatives designated as hedging instruments Balance Sheet Location Fair Value Interest rate contracts Other assets $ 8,928 The following table summarizes the location and amount of the gain or loss on the hedged item attributable to the changes in the LIBOR swap rate and the offsetting gain or loss on the related interest rate swap agreements for the years ended March 31, 2016 and 2015. The difference represents hedge ineffectiveness (amounts in thousands): Year ended March 31, 2016 2015 Income Statement Classification Gain (Loss) on Senior Subordinated Convertible Debentures Gain (Loss) on Interest Rate Swap Gain (Loss) on Senior Subordinated Convertible Debentures Gain (Loss) on Interest Rate Swap Other income (expense) $ (18,060 ) $ 16,345 $ (8,302 ) $ 8,928

Net income per common share a53

Net income per common share attributable to Microchip Technology Stockholders (Tables)	12 Months Ended
	Mar. 31, 2016
Earnings Per Share [Abstract]
Schedule computation of basic and diluted earnings per share	The following table sets forth the computation of basic and diluted net income per common share (in thousands, except per share amounts): Year ended March 31, 2016 2015 2014 Net income attributable to Microchip Technology $ 324,132 $ 369,009 $ 395,281 Weighted average common shares outstanding 203,384 200,937 198,291 Dilutive effect of stock options and RSUs 3,350 3,642 3,910 Dilutive effect of 2037 junior subordinated convertible debentures 10,654 18,982 15,429 Weighted average common and potential common shares outstanding 217,388 223,561 217,630 Basic net income per common share attributable to Microchip Technology stockholders $ 1.59 $ 1.84 $ 1.99 Diluted net income per common share attributable to Microchip Technology stockholders $ 1.49 $ 1.65 $ 1.82

Quarterly Results (Unaudited) (

Quarterly Results (Unaudited) (Tables)	12 Months Ended
	Mar. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Quarterly financial data	The following table presents the Company's selected unaudited quarterly operating results for the eight quarters ended March 31, 2016 . The Company believes that all adjustments of a normal recurring nature have been made to present fairly the related quarterly results (in thousands, except per share amounts): Fiscal 2016 First Quarter Second Quarter Third Quarter Fourth Quarter Total Net sales $ 533,952 $ 541,391 $ 540,344 $ 557,647 $ 2,173,334 Gross profit 309,017 300,950 292,718 302,779 1,205,464 Operating income 121,319 74,948 76,132 79,946 352,345 Net income 130,460 64,899 61,211 67,355 323,925 Less: Net loss attributable to noncontrolling interests 207 — — — 207 Net income attributable to Microchip Technology 130,667 64,899 61,211 67,355 324,132 Diluted net income per common share attributable to Microchip Technology stockholders 0.60 0.30 0.28 0.31 1.49 Fiscal 2015 First Quarter Second Quarter Third Quarter Fourth Quarter Total Net sales $ 528,876 $ 546,243 $ 528,710 $ 543,207 $ 2,147,036 Gross profit 306,519 307,454 301,959 313,632 1,229,564 Operating income 115,946 101,318 98,009 110,347 425,620 Net income 89,909 92,038 84,798 98,580 365,325 Less: Net loss attributable to noncontrolling interests — 1,603 1,259 822 3,684 Net income attributable to Microchip Technology 89,909 93,641 86,057 99,402 369,009 Diluted net income per common share attributable to Microchip Technology stockholders 0.40 0.42 0.39 0.45 1.65 Refer to Note 3, Special Charges, for an explanation of the special charges included in operating income in fiscal 2016 and fiscal 2015 . Refer to Note 15, 2.125% Junior Subordinated Convertible Debentures, for an explanation of the loss on retirement of convertible debentures of approximately $ 50.6 million included in net income (loss) during the fourth quarter of fiscal 2015. Refer to Note 4, Investments, for an explanation of the net realized gain from sales of available-for-sale marketable equity securities included in net income during the fourth quarter of fiscal 2015 and the first quarter of fiscal 2016.

Supplemental Financial Inform55

Supplemental Financial Information (Tables)	12 Months Ended
	Mar. 31, 2016
Supplemental Cash Flow Information [Abstract]
Schedule of Valuation and Qualifying Accounts Disclosure Deferred Tax Assets	A summary of additions and deductions related to the valuation allowance for deferred tax asset accounts for the years ended March 31, 2016 , 2015 and 2014 follows (amounts in thousands): Balance at Beginning of Year Additions Charged to Costs and Expenses Additions Charged to Other Accounts Deductions Balance at End of Year Valuation allowance for deferred tax assets: Fiscal Year 2016 $ 116,482 $ 5,535 $ 47,834 $ (8,017 ) $ 161,834 Fiscal Year 2015 93,811 — 36,957 (14,286 ) 116,482 Fiscal Year 2014 88,637 — 5,174 — 93,811
Schedule of Valuation and Qualifying Accounts Disclosure Allowance for Doubtful Accounts	A summary of additions and deductions related to the allowance for doubtful accounts for the years ended March 31, 2016 , 2015 and 2014 follows (amounts in thousands): Balance at Beginning of Year Additions Charged to Costs and Expenses Deductions (1) Balance at End of Year Allowance for doubtful accounts: Fiscal Year 2016 $ 2,621 $ 59 $ (140 ) $ 2,540 Fiscal Year 2015 2,918 104 (401 ) 2,621 Fiscal Year 2014 2,764 245 (91 ) 2,918
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	The following tables present the changes in the components of accumulated other comprehensive income (AOCI) for the years ended March 31, 2016 and March 31, 2015 : Year ended March 31, 2016 Unrealized Holding Gains (Losses) Available-for-sale Securities Minimum Pension Liability Foreign Currency Total Balance at March 31, 2015 $ 14,537 $ 13 $ (3,474 ) $ 11,076 Other comprehensive (loss) income before reclassifications (3,241 ) 31 — (3,210 ) Amounts reclassified from accumulated other comprehensive (loss) income (10,948 ) — — (10,948 ) Net other comprehensive (loss) income (14,189 ) 31 — (14,158 ) Purchase of shares from noncontrolling interest — — (275 ) (275 ) Balance at March 31, 2016 $ 348 $ 44 $ (3,749 ) $ (3,357 ) Year ended March 31, 2015 Unrealized Holding Gains (Losses) Available-for-sale Securities Minimum Pension Liability Foreign Currency Total Balance at March 31, 2014 $ (528 ) $ 140 $ 1,439 $ 1,051 Other comprehensive income (loss) before reclassifications 33,759 (127 ) (4,322 ) 29,310 Amounts reclassified from accumulated other comprehensive income (loss) (18,694 ) — — (18,694 ) Net other comprehensive income (loss) 15,065 (127 ) (4,322 ) 10,616 Purchase of shares from noncontrolling interest — — (591 ) (591 ) Balance at March 31, 2015 $ 14,537 $ 13 $ (3,474 ) $ 11,076
Reclassification out of Accumulated Other Comprehensive Income [Table Text Block]	The table below details where reclassifications of realized transactions out of AOCI are recorded on the consolidated statements of income. Year ended March 31, Description of AOCI Component 2016 2015 2014 Related Statement of Income Line Unrealized gains on available-for-sale securities $ 10,948 $ 18,706 $ 2,371 Other income Taxes — (12 ) (776 ) Provision for income taxes Reclassification of realized transactions, net of taxes $ 10,948 $ 18,694 $ 1,595 Net Income

Subsequent Events (Tables)

Subsequent Events (Tables) - Atmel Corporation [Member]	12 Months Ended
	Mar. 31, 2016
Business Acquisition [Line Items]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]	Assets acquired April 4, 2016 Cash and cash equivalents $ 210,252 Accounts receivable, net 195,481 Inventories 403,708 Prepaid expenses and other current assets 35,299 Property, plant and equipment, net 131,154 Goodwill 1,400,814 Purchased intangible assets 1,551,100 Long-term deferred tax assets 157,929 Other assets 45,747 Total assets acquired 4,131,484 Liabilities assumed Accounts payable (59,470 ) Other current liabilities (133,012 ) Long-term line of credit (192,300 ) Deferred tax liabilities (155,553 ) Long-term income tax payable (49,965 ) Other long-term liabilities (67,577 ) Total liabilities assumed (657,877 ) Purchase price allocated $ 3,473,607
Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination [Table Text Block]	Purchased Intangible Assets Useful Life April 4, 2016 (in years) (in thousands) Core/developed technology 10-15 $ 988,400 In-process technology 10-15 114,500 Customer-related 5 435,900 Backlog 1-2 12,300 Total purchased intangible assets $ 1,551,100
Business Acquisition, Pro Forma Information [Table Text Block]	Year ended March 31, 2016 2015 Net sales $ 3,345,790 $ 3,560,370 Net income $ 167,705 $ 116,618 Basic earnings per share $ 0.79 $ 0.55 Diluted earnings per share $ 0.74 $ 0.50

Significant Accounting Polici57

Significant Accounting Policies (Details) $ in Thousands	12 Months Ended
	Mar. 31, 2016USD ($)	Mar. 31, 2015USD ($)
Accounting Policies [Abstract]
Deferred revenue on shipments to distributors	$ 267,200	$ 260,900
Deferred cost of sales on shipments to distributors	83,800	94,800
Deferred income on shipments to distributors	183,432	166,128
Property, Plant and Equipment [Line Items]
Amount of distributor advances, included in deferred income on shipments to distributors in consolidated balance sheets	$ 102,900	$ 116,000
Number of days requiring distributor to settle receivable balances (in days)	30
Minimum | Building and Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	10 years
Minimum | Machinery and equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Maximum | Building and Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	40 years
Maximum | Machinery and equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	7 years

Business Acquisitions (Narrativ

Business Acquisitions (Narrative) (Details) - USD ($) $ in Thousands	Aug. 03, 2015	Mar. 31, 2016	Mar. 31, 2015	Jul. 17, 2014
Business Acquisition [Line Items]
Non cash consideration transferred in the form of share-based payment awards (amount)		$ 4,052
Micrel Incorporated [Member]
Business Acquisition [Line Items]
Cash paid for shares	$ 430,000
Shares issued in Micrel acquisition	8,626,795
Non cash consideration transferred in the form of share-based payment awards (amount)	$ 4,100
Cash paid in a business combination for employee vested stock awards	13,100
Total consideration transferred	816,200
Net deferred tax liability for future amortization expense of acquired intangible assets	99,700
Long-term deferred tax assets	$ 11,400
Revenue of acquiree included in statement of income since the acquisition date		$ 116,400
ISSC Technologies Corporation [Member]
Business Acquisition [Line Items]
Percentage of interest acquired in acquisition				83.50%
Supertex Inc. [Member]
Business Acquisition [Line Items]
Non cash consideration transferred in the form of share-based payment awards (amount)			$ 1,622

Business Acquisitions (Schedule

Business Acquisitions (Schedule of Purchase Price Allocation) (Details) - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2016	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015
Business Acquisition [Line Items]
Goodwill	$ 1,012,652			$ 571,271
Micrel Incorporated [Member]
Business Acquisition [Line Items]
Cash and cash equivalents	99,196	$ 99,196
Accounts receivable, net	14,096	12,296
Inventories	73,468	78,967
Prepaid expenses and other current assets	10,652	10,548
Property, plant and equipment, net	38,566	38,566
Goodwill	440,992	437,060
Purchased intangible assets	273,500	274,800
Other assets	4,268	4,268
Total assets acquired	954,738	955,701
Accounts payable	(11,068)	(11,068)
Other current liabilities	(31,641)	(30,241)
Deferred tax liability	(88,035)	(88,796)
Long-term income tax payable	(7,637)	(9,239)
Other long-term liabilities	(127)	(127)
Total liabilities assumed	(138,508)	(139,471)
Net assets acquired	816,230	$ 816,230
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustments [Abstract]
Accounts receivable, net	1,800
Inventories	(5,499)
Prepaid expenses and other current assets	104
Goodwill	3,932
Purchased intangible assets	(1,300)
Total assets acquired	(963)
Other current liabilities	(1,400)
Deferred tax liabilities	761
Long-term income tax payable	1,602
Total liabilities assumed	$ 963
ISSC Technologies Corporation [Member]
Business Acquisition [Line Items]
Cash and cash equivalents			$ 15,120
Short-term investments			27,063
Accounts receivable, net			8,792
Inventories			16,542
Prepaid expenses and other current assets			2,501
Property, plant and equipment, net			2,637
Goodwill			154,788
Purchased intangible assets			147,800
Other assets			1,370
Total assets acquired			376,613
Accounts payable			(9,860)
Other current liabilities			(16,535)
Deferred tax liability			(25,126)
Long-term income tax payable			(4,791)
Other long-term liabilities			(245)
Total liabilities assumed			(56,557)
Net assets acquired			320,056
Less: noncontrolling interest			(52,467)
Net assets acquired			$ 267,589
Supertex Inc. [Member]
Business Acquisition [Line Items]
Cash and cash equivalents				14,790
Short-term investments				140,984
Accounts receivable, net				7,047
Inventories				27,630
Prepaid expenses				1,493
Deferred tax assets				2,456
Other current assets				12,625
Property, plant and equipment, net				15,679
Goodwill				143,160
Purchased intangible assets				89,600
Other assets				325
Total assets acquired				455,789
Accounts payable				(8,481)
Other current liabilities				(19,224)
Deferred tax liability				(32,511)
Long-term income tax payable				(3,796)
Total liabilities assumed				(64,012)
Net assets acquired				$ 391,777

Business Acquisitions (Schedu60

Business Acquisitions (Schedule of Purchased Intangible Assets) (Details) - USD ($) $ in Thousands	Aug. 03, 2015	Jul. 17, 2014	Apr. 01, 2014	Mar. 31, 2016
Core/developed technology
Business Acquisition [Line Items]
Purchased intangible assets				$ 175,800
In-process technology
Business Acquisition [Line Items]
Purchased intangible assets				21,000
Backlog
Business Acquisition [Line Items]
Purchased intangible assets				$ 5,600
Micrel Incorporated [Member]
Business Acquisition [Line Items]
Purchased intangible assets	$ 273,500
Micrel Incorporated [Member] | Core/developed technology
Business Acquisition [Line Items]
Useful life	10 years
Purchased intangible assets	$ 175,800
Micrel Incorporated [Member] | In-process technology
Business Acquisition [Line Items]
Useful life	10 years
Purchased intangible assets	$ 21,000
Micrel Incorporated [Member] | Customer-related
Business Acquisition [Line Items]
Useful life	5 years
Purchased intangible assets	$ 71,100
Micrel Incorporated [Member] | Backlog
Business Acquisition [Line Items]
Useful life	1 year
Purchased intangible assets	$ 5,600
ISSC Technologies Corporation [Member]
Business Acquisition [Line Items]
Purchased intangible assets		$ 147,800
ISSC Technologies Corporation [Member] | Core/developed technology
Business Acquisition [Line Items]
Useful life		10 years
Purchased intangible assets		$ 68,900
ISSC Technologies Corporation [Member] | In-process technology
Business Acquisition [Line Items]
Useful life		10 years
Purchased intangible assets		$ 27,200
ISSC Technologies Corporation [Member] | Customer-related
Business Acquisition [Line Items]
Useful life		3 years
Purchased intangible assets		$ 51,100
ISSC Technologies Corporation [Member] | Backlog
Business Acquisition [Line Items]
Useful life		1 year
Purchased intangible assets		$ 600
Supertex Inc. [Member]
Business Acquisition [Line Items]
Purchased intangible assets			$ 89,600
Supertex Inc. [Member] | Core/developed technology
Business Acquisition [Line Items]
Useful life			10 years
Purchased intangible assets			$ 68,900
Supertex Inc. [Member] | In-process technology
Business Acquisition [Line Items]
Useful life			10 years
Purchased intangible assets			$ 1,900
Supertex Inc. [Member] | Customer-related
Business Acquisition [Line Items]
Useful life			2 years
Purchased intangible assets			$ 17,700
Supertex Inc. [Member] | Backlog
Business Acquisition [Line Items]
Useful life			1 year
Purchased intangible assets			$ 1,100

Business Acquisitions (Schedu61

Business Acquisitions (Schedule of Proforma Results) (Details) - Micrel Incorporated [Member] - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Business Acquisition [Line Items]
Net sales	$ 2,283,517	$ 2,352,727
Net income	$ 365,654	$ 278,673
Basic earnings per share	$ 1.80	$ 1.39
Diluted earnings per share	$ 1.68	$ 1.25

Special Charges (Details)

Special Charges (Details) - Unusual or Infrequent Item [Member] - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Unusual or Infrequent Item [Line Items]
Other Nonrecurring Expense	$ 4	$ 2.8	$ 3
Legal settlement costs	4.3
Unusual or Infrequent Item, Insurance Proceeds	11.5
Severance related, office closing and other costs	$ 11.2

Summary of Available for Sale (

Summary of Available for Sale (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Mar. 31, 2015
Summary of available-for-sale securities [Line Items]
Available-for-sale, adjusted cost	$ 471,485	$ 1,719,843
Available-for-sale, gross unrealized gains	447	15,011
Available-for-sale, gross unrealized losses	(99)	(474)
Available-for-sale, estimated fair value	471,833	1,734,380
Government agency bonds [Member]
Summary of available-for-sale securities [Line Items]
Available-for-sale, adjusted cost	468,290	741,780
Available-for-sale, gross unrealized gains	439	676
Available-for-sale, gross unrealized losses	(99)	(200)
Available-for-sale, estimated fair value	468,630	742,256
Municipal bonds [Member]
Summary of available-for-sale securities [Line Items]
Available-for-sale, adjusted cost		41,552
Available-for-sale, gross unrealized gains		155
Available-for-sale, gross unrealized losses		(9)
Available-for-sale, estimated fair value		41,698
Auction rate securities [Member]
Summary of available-for-sale securities [Line Items]
Available-for-sale, adjusted cost		9,825
Available-for-sale, gross unrealized gains		0
Available-for-sale, gross unrealized losses		0
Available-for-sale, estimated fair value		9,825
Time Deposits [Member]
Summary of available-for-sale securities [Line Items]
Available-for-sale, adjusted cost		506
Available-for-sale, gross unrealized gains		0
Available-for-sale, gross unrealized losses		0
Available-for-sale, estimated fair value		506
Corporate bonds and debt [Member]
Summary of available-for-sale securities [Line Items]
Available-for-sale, adjusted cost	1,000	924,818
Available-for-sale, gross unrealized gains	0	2,376
Available-for-sale, gross unrealized losses	0	(265)
Available-for-sale, estimated fair value	1,000	926,929
Equity Securities [Member]
Summary of available-for-sale securities [Line Items]
Available-for-sale, adjusted cost	2,195	1,362
Available-for-sale, gross unrealized gains	8	11,804
Available-for-sale, gross unrealized losses	0	0
Available-for-sale, estimated fair value	$ 2,203	$ 13,166

Investments AFS (Details)

Investments AFS (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	$ 471,833	$ 1,734,380
Amount of short-term investments	353,284	1,351,054
Amount of long-term investments	118,549	383,326
Proceeds for sale of available-for-sale securities	1,501,500	273,900	$ 135,300
Realized gain on available-for-sale investments	13,727	18,469	$ 0
Corporate bonds and debt [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	1,000	926,929
Amount of corporate debt securities with no contractual maturity excluded from estimated fair value of available-for-sale securities		6,200
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	$ 2,203	$ 13,166

Investments Continuous Unrealiz

Investments Continuous Unrealized Loss Position (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Mar. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale securities in a continuous unrealized loss position, less than twelve months	$ 148,562	$ 339,361
Accumulated loss, available-for-sale securities in a continuous unrealized loss position, less than twelve months	(99)	(370)
Fair value of available-for-sale securities in a continuous unrealized loss position, greater than twelve months	1,000	48,963
Accumulated loss, available-for-sale securities in a continuous unrealized loss position, greater than twelve months	0	(104)
Fair value of available-for-sale securities in a continuous unrealized loss position	149,562	388,324
Accumulated loss, available-for-sale securities in a continuous unrealized loss position	(99)	(474)
Government agency bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale securities in a continuous unrealized loss position, less than twelve months	148,562	162,948
Accumulated loss, available-for-sale securities in a continuous unrealized loss position, less than twelve months	(99)	(142)
Fair value of available-for-sale securities in a continuous unrealized loss position, greater than twelve months	0	29,942
Accumulated loss, available-for-sale securities in a continuous unrealized loss position, greater than twelve months	0	(58)
Fair value of available-for-sale securities in a continuous unrealized loss position	148,562	192,890
Accumulated loss, available-for-sale securities in a continuous unrealized loss position	(99)	(200)
Municipal bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale securities in a continuous unrealized loss position, less than twelve months		13,318
Accumulated loss, available-for-sale securities in a continuous unrealized loss position, less than twelve months		(9)
Fair value of available-for-sale securities in a continuous unrealized loss position, greater than twelve months		0
Accumulated loss, available-for-sale securities in a continuous unrealized loss position, greater than twelve months		0
Fair value of available-for-sale securities in a continuous unrealized loss position		13,318
Accumulated loss, available-for-sale securities in a continuous unrealized loss position		(9)
Corporate bonds and debt [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale securities in a continuous unrealized loss position, less than twelve months	0	163,095
Accumulated loss, available-for-sale securities in a continuous unrealized loss position, less than twelve months	0	(219)
Fair value of available-for-sale securities in a continuous unrealized loss position, greater than twelve months	1,000	19,021
Accumulated loss, available-for-sale securities in a continuous unrealized loss position, greater than twelve months	0	(46)
Fair value of available-for-sale securities in a continuous unrealized loss position	1,000	182,116
Accumulated loss, available-for-sale securities in a continuous unrealized loss position	$ 0	$ (265)

AFS, Debt Maturities (Details)

AFS, Debt Maturities (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Mar. 31, 2015
Schedule of available-for-sale securities, debt maturities [Line Items]
Available-for-sale, adjusted cost	$ 471,485	$ 1,719,843
Available-for-sale, gross unrealized losses	(99)	(474)
Available-for-sale, estimated fair value	471,833	1,734,380
Due in one year or less [Member]
Schedule of available-for-sale securities, debt maturities [Line Items]
Available-for-sale, adjusted cost	41,078	224,531
Available-for-sale, gross unrealized gains	5	512
Available-for-sale, gross unrealized losses	(5)	(34)
Available-for-sale, estimated fair value	41,078	225,009
Due after one year and through five years [Member]
Schedule of available-for-sale securities, debt maturities [Line Items]
Available-for-sale, adjusted cost	428,212	1,395,685
Available-for-sale, gross unrealized gains	434	2,648
Available-for-sale, gross unrealized losses	(94)	(330)
Available-for-sale, estimated fair value	428,552	1,398,003
Due after five years and through ten years [Member]
Schedule of available-for-sale securities, debt maturities [Line Items]
Available-for-sale, adjusted cost	0	82,250
Available-for-sale, gross unrealized gains	0	47
Available-for-sale, gross unrealized losses	0	(110)
Available-for-sale, estimated fair value	0	82,187
Due after ten years [Member]
Schedule of available-for-sale securities, debt maturities [Line Items]
Available-for-sale, adjusted cost	0	9,825
Available-for-sale, gross unrealized gains	0	0
Available-for-sale, gross unrealized losses	0	0
Available-for-sale, estimated fair value	0	9,825
Total Maturities Member
Schedule of available-for-sale securities, debt maturities [Line Items]
Available-for-sale, adjusted cost	469,290	1,712,291
Available-for-sale, gross unrealized gains	439	3,207
Available-for-sale, gross unrealized losses	(99)	(474)
Available-for-sale, estimated fair value	469,630	1,715,024
Equity Securities [Member]
Schedule of available-for-sale securities, debt maturities [Line Items]
Available-for-sale, adjusted cost	2,195	1,362
Available-for-sale, gross unrealized losses	0	0
Available-for-sale, estimated fair value	2,203	13,166
Corporate Bond Securities [Member]
Schedule of available-for-sale securities, debt maturities [Line Items]
Available-for-sale, adjusted cost	1,000	924,818
Available-for-sale, gross unrealized losses	0	(265)
Available-for-sale, estimated fair value	$ 1,000	$ 926,929

Measured on Recurring Basis (De

Measured on Recurring Basis (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2016
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	$ 1,734,380	$ 471,833
Equity Securities [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	13,166	2,203
Government agency bonds [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	742,256	468,630
Corporate Bond Securities [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	926,929	1,000
Municipal bonds [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	41,698
Auction rate securities [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	9,825
Available-for-sale Securities, Other Disclosure Items [Abstract]
Value of auction rate securities for which recent auctions were unsuccessful	9,800
Par Value of auction rate securities for which recent auctions were unsuccessful	$ 22,400
Auction rate securities [Member] | Minimum
Available-for-sale Securities, Other Disclosure Items [Abstract]
Discount rate	2.00%
Liquidity risk premium (percentage)	9.10%
Anticipated liquidity horizon	7 years
Auction rate securities [Member] | Maximum
Available-for-sale Securities, Other Disclosure Items [Abstract]
Discount rate	2.50%
Liquidity risk premium (percentage)	29.50%
Anticipated liquidity horizon	10 years
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Total assets measured at fair value	$ 2,351,123	2,564,584
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Total assets measured at fair value	292,999	1,789,649
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Total assets measured at fair value	2,042,109	774,935
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Total assets measured at fair value	16,015	0
Fair Value, Measurements, Recurring [Member] | Cash and Cash Equivalents [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Cash and cash equivalents	279,833	1,787,446
Fair Value, Measurements, Recurring [Member] | Cash and Cash Equivalents [Member] | Demand and time deposits [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Cash and cash equivalents	327,982	305,305
Fair Value, Measurements, Recurring [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Cash and cash equivalents	279,833	1,787,446
Fair Value, Measurements, Recurring [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member] | Demand and time deposits [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Cash and cash equivalents	0	0
Fair Value, Measurements, Recurring [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Cash and cash equivalents	0	0
Fair Value, Measurements, Recurring [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member] | Demand and time deposits [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Cash and cash equivalents	327,982	305,305
Fair Value, Measurements, Recurring [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Cash and cash equivalents	0	0
Fair Value, Measurements, Recurring [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member] | Demand and time deposits [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Cash and cash equivalents	0	0
Fair Value, Measurements, Recurring [Member] | Short-term Investments [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	13,166	2,203
Fair Value, Measurements, Recurring [Member] | Short-term Investments [Member] | Government agency bonds [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	549,737	350,081
Fair Value, Measurements, Recurring [Member] | Short-term Investments [Member] | Corporate Bond Securities [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	756,664	1,000
Fair Value, Measurements, Recurring [Member] | Short-term Investments [Member] | Time Deposits [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	506
Fair Value, Measurements, Recurring [Member] | Short-term Investments [Member] | Municipal bonds [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	30,981
Fair Value, Measurements, Recurring [Member] | Short-term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	13,166	2,203
Fair Value, Measurements, Recurring [Member] | Short-term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Government agency bonds [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring [Member] | Short-term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Corporate Bond Securities [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring [Member] | Short-term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Time Deposits [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	0
Fair Value, Measurements, Recurring [Member] | Short-term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Municipal bonds [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	0
Fair Value, Measurements, Recurring [Member] | Short-term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring [Member] | Short-term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Government agency bonds [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	549,737	350,081
Fair Value, Measurements, Recurring [Member] | Short-term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Corporate Bond Securities [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	756,664	1,000
Fair Value, Measurements, Recurring [Member] | Short-term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Time Deposits [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	506
Fair Value, Measurements, Recurring [Member] | Short-term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Municipal bonds [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	30,981
Fair Value, Measurements, Recurring [Member] | Short-term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring [Member] | Short-term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Government agency bonds [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring [Member] | Short-term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Corporate Bond Securities [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring [Member] | Short-term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Time Deposits [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	0
Fair Value, Measurements, Recurring [Member] | Short-term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Municipal bonds [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	0
Fair Value, Measurements, Recurring [Member] | Other Long-term Investments [Member] | Government agency bonds [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	192,519	118,549
Fair Value, Measurements, Recurring [Member] | Other Long-term Investments [Member] | Corporate Bond Securities [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	170,265
Fair Value, Measurements, Recurring [Member] | Other Long-term Investments [Member] | Municipal bonds [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	10,717
Fair Value, Measurements, Recurring [Member] | Other Long-term Investments [Member] | Auction rate securities [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	9,825
Fair Value, Measurements, Recurring [Member] | Other Long-term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Government agency bonds [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	0	0
Fair Value, Measurements, Recurring [Member] | Other Long-term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Corporate Bond Securities [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	0
Fair Value, Measurements, Recurring [Member] | Other Long-term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Municipal bonds [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	0
Fair Value, Measurements, Recurring [Member] | Other Long-term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Auction rate securities [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	0
Fair Value, Measurements, Recurring [Member] | Other Long-term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Government agency bonds [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	192,519	118,549
Fair Value, Measurements, Recurring [Member] | Other Long-term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Corporate Bond Securities [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	164,075
Fair Value, Measurements, Recurring [Member] | Other Long-term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Municipal bonds [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	10,717
Fair Value, Measurements, Recurring [Member] | Other Long-term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Auction rate securities [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	0
Fair Value, Measurements, Recurring [Member] | Other Long-term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Government agency bonds [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	0	$ 0
Fair Value, Measurements, Recurring [Member] | Other Long-term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Corporate Bond Securities [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	6,190
Fair Value, Measurements, Recurring [Member] | Other Long-term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Municipal bonds [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	0
Fair Value, Measurements, Recurring [Member] | Other Long-term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Auction rate securities [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Available-for-sale Securities	9,825
Fair Value, Measurements, Recurring [Member] | Other Noncurrent Assets [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	8,928
Fair Value, Measurements, Recurring [Member] | Other Noncurrent Assets [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	0
Fair Value, Measurements, Recurring [Member] | Other Noncurrent Assets [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	8,928
Fair Value, Measurements, Recurring [Member] | Other Noncurrent Assets [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities, as Classified on the Condensed Consolidated Balance Sheets [Abstract]
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	$ 0

Unobservable Input Reconciliati

Unobservable Input Reconciliation Assets (Details) $ in Thousands	12 Months Ended
	Mar. 31, 2016USD ($)
Fair value, assets measured on recurring basis, unobservable input reconciliation [Line Items]
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings and Gain (Loss) Included in Other Comprehensive Income (Loss)	$ (1,215)
Auction rate securities [Member]
Fair value, assets measured on recurring basis, unobservable input reconciliation [Line Items]
Fair value, measurement with unobservable inputs reconciliation, beginning	9,825
Included in earnings	2,780
Purchases, sales, issuances, and settlements, net	(12,605)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	0
Fair value, measurement with unobservable inputs reconciliation, ending	0
Corporate Debt [Member]
Fair value, assets measured on recurring basis, unobservable input reconciliation [Line Items]
Fair value, measurement with unobservable inputs reconciliation, beginning	6,190
Included in earnings	(3,995)
Purchases, sales, issuances, and settlements, net	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3	(2,195)
Fair value, measurement with unobservable inputs reconciliation, ending	0
Total Gains (Losses) [Member]
Fair value, assets measured on recurring basis, unobservable input reconciliation [Line Items]
Included in earnings	$ (1,215)

Assets Not Recorded at Fair Val

Assets Not Recorded at Fair Value on a Recurring Basis (Details) $ in Millions	12 Months Ended
	Mar. 31, 2014USD ($)
Investments Not Recorded at Fair Value on a Recurring Basis [Abstract]
Cost-method Investments, Other than Temporary Impairment	$ 0.7

Fair Value of Financial Instr70

Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Mar. 31, 2015
Fair Value | Senior Subordinated Convertible Debentures Due 2025 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for Subordinated Convertible Debentures	$ 1,762,088	$ 1,787,531
Fair Value | Junior Subordinated Convertible Debentures Due2037 Member
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for Subordinated Convertible Debentures	1,143,117	1,124,125
Carrying Amount | Senior Subordinated Convertible Debentures Due 2025 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for Subordinated Convertible Debentures	1,234,733	1,174,036
Carrying Amount | Junior Subordinated Convertible Debentures Due2037 Member
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value disclosure for Subordinated Convertible Debentures	$ 196,304	$ 190,870

Accounts Receivable (Details)

Accounts Receivable (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Mar. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivable amounts	$ 292,723	$ 276,558
Less allowance for doubtful accounts	2,540	2,621
Accounts receivable, net	290,183	273,937
Trade Accounts Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivable amounts	289,013	269,844
Other Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivable amounts	$ 3,710	$ 6,714

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Mar. 31, 2015
Inventories [Abstract]
Raw materials	$ 12,179	$ 13,263
Work in process	208,283	197,565
Finished goods	86,353	68,628
Inventory, Net	$ 306,815	$ 279,456

Assets Held for Sale (Details)

Assets Held for Sale (Details) - Property, Plant and Equipment, Other Types [Member] - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Long Lived Assets Held-for-sale [Line Items]
Assets Held-for-sale, Long Lived, Fair Value Disclosure		$ 14
Proceeds from Sale of Property, Plant, and Equipment	$ 14.3

Property, Plant and Equipment74

Property, Plant and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Property, Plant and Equipment [Line Items]
Property, plant, and equipment costs	$ 2,267,273	$ 2,142,416
Accumulated depreciation	1,657,877	1,560,844
Property, plant and equipment, net	609,396	581,572
Depreciation expense	103,900	97,300	$ 89,700
Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment costs	63,907	55,624
Building and Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment costs	458,379	434,403
Machinery and equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment costs	1,645,617	1,576,074
Projects in progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant, and equipment costs	$ 99,370	$ 76,315

Noncontrolling interests roll f

Noncontrolling interests roll forward (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance				$ 16,372					$ 16,372
Additions due to acquisition of controlling interest in ISSC										$ 52,467
Net loss attributable to noncontrolling interests	$ 0	$ 0	$ 0	(207)	$ (822)	$ (1,259)	$ (1,603)	$ 0	(207)	(3,684)	$ 0
Other comprehensive loss attributable to noncontrolling interests									0	(866)	0
Purchase of additional interests									(18,051)	(32,095)
Balance	0				16,372				0	16,372
Noncontrolling Interest [Member]
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balance				$ 16,372				$ 0	16,372	0
Additions due to acquisition of controlling interest in ISSC										52,467
Net loss attributable to noncontrolling interests									(207)	(3,684)
Other comprehensive loss attributable to noncontrolling interests										(866)
Purchase of additional interests									(16,165)	(31,849)
Other										304
Balance	$ 0				$ 16,372				$ 0	$ 16,372	$ 0

Change in Parent Ownership (Det

Change in Parent Ownership (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Net Income Attributable to Microchip Technology stockholders	$ 67,355	$ 61,211	$ 64,899	$ 130,667	$ 99,402	$ 86,057	$ 93,641	$ 89,909	$ 324,132	$ 369,009	$ 395,281
(Decrease) increase in paid-in capital for purchase of additional interests									(275)	(591)
Parent [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Net Income Attributable to Microchip Technology stockholders									324,132	369,009
(Decrease) increase in paid-in capital for purchase of additional interests									(1,611)	345
Increase in paid-in capital for converted stock options									0	1,094
Net transfers (to) from noncontrolling interest									(1,611)	1,439
Change from net income attributable to Microchip Technology stockholders and transfers (to) from noncontrolling interest									$ 322,521	$ 370,448

Intangible Assets, by Major Cla

Intangible Assets, by Major Class (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 1,075,013	$ 898,086
Accumulated Amortization	(468,664)	(393,669)
Net Amount	606,349	504,417
In-process technology reaching technological feasibility and reclassified	33,800
Projected Amortization Expense
2,017	137,321
2,018	110,811
2,019	94,573
2,020	76,683
2,021	50,974
Amortization of acquired intangible assets	179,300	181,000	$ 99,400
Impairment of intangible assets	629	1,881	350
Cost of sales
Projected Amortization Expense
Amortization of acquired intangible assets	3,600	3,800	4,700
Operating Expense
Projected Amortization Expense
Amortization of acquired intangible assets	$ 175,700	177,200	$ 94,700
Minimum
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	1 year
Maximum
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	15 years
Core and developed technology
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 724,883	549,415
Accumulated Amortization	(255,460)	(189,149)
Net Amount	469,423	360,266
Acquired Finite-lived Intangible Asset, Amount	$ 175,800
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	10 years
Customer-related
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 278,542	262,769
Accumulated Amortization	(200,331)	(192,283)
Net Amount	78,211	70,486
Acquired Finite-lived Intangible Asset, Amount	$ 71,100
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	5 years
Trademarks and trade names
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 11,700	13,180
Accumulated Amortization	(7,571)	(6,979)
Net Amount	4,129	6,201
Backlog
Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Asset, Amount	$ 5,600
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	1 year
In-process technology
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 54,308	67,142
Accumulated Amortization	0	0
Net Amount	54,308	67,142
Acquired Finite-lived Intangible Asset, Amount	$ 21,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	10 years
Distribution rights
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 5,580	5,580
Accumulated Amortization	(5,302)	(5,258)
Net Amount	$ 278	$ 322

Goodwill by Reporting Segment (

Goodwill by Reporting Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 571,271
Goodwill, ending balance	1,012,652	$ 571,271
Supertex Inc. [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	143,160
Goodwill, ending balance		143,160
Micrel Incorporated [Member]
Goodwill [Roll Forward]
Goodwill, ending balance	440,992
Semiconductor products [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	552,071	256,897
Goodwill, ending balance	993,452	552,071
Semiconductor products [Member] | Other business acquisitions [Member]
Goodwill [Roll Forward]
Purchase accounting adjustments		624
Semiconductor products [Member] | Supertex Inc. [Member]
Goodwill [Roll Forward]
Additions due to business combination		143,160
Semiconductor products [Member] | ISSC Technologies Corporation [Member]
Goodwill [Roll Forward]
Additions due to business combination		154,399
Purchase accounting adjustments	389
Foreign currency translation adjustments		(3,009)
Semiconductor products [Member] | Micrel Incorporated [Member]
Goodwill [Roll Forward]
Additions due to business combination	440,992
Technology licensing [Member]
Goodwill [Roll Forward]
Goodwill, beginning balance	19,200	19,200
Goodwill, ending balance	19,200	19,200
Technology licensing [Member] | Other business acquisitions [Member]
Goodwill [Roll Forward]
Purchase accounting adjustments		0
Technology licensing [Member] | Supertex Inc. [Member]
Goodwill [Roll Forward]
Additions due to business combination		0
Technology licensing [Member] | ISSC Technologies Corporation [Member]
Goodwill [Roll Forward]
Additions due to business combination		0
Purchase accounting adjustments	0
Foreign currency translation adjustments		$ 0
Technology licensing [Member] | Micrel Incorporated [Member]
Goodwill [Roll Forward]
Additions due to business combination	$ 0

Income tax (benefit) provision

Income tax (benefit) provision from continuing operations (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Income Tax Disclosure [Abstract]
Excess Tax Benefit from Share-based Compensation, Operating Activities	$ 758	$ 1,216	$ 1,411
Results of Operations, Income before Income Taxes [Abstract]
U.S.	(75,515)	(944)	28,245
Foreign	356,808	346,851	404,109
Income before income taxes	281,293	345,907	432,354
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current Federal Tax Expense (Benefit)	(3,966)	(3,185)	992
Current State and Local Tax Expense (Benefit)	(188)	(24)	64
Current Foreign Tax Expense (Benefit)	21,947	16,602	30,697
Current Income Tax Expense (Benefit)	17,793	13,393	31,753
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred Federal Income Tax Expense (Benefit)	(42,207)	(22,641)	14,445
Deferred State and Local Income Tax Expense (Benefit)	(1,990)	(1,562)	929
Deferred Foreign Income Tax Expense (Benefit)	(16,228)	(8,608)	(10,054)
Deferred Income Tax Expense (Benefit)	(60,425)	(32,811)	5,320
Income tax provision	(42,632)	(19,418)	37,073
Income Tax Expense (Benefit), Continuing Operations, Income Tax Reconciliation [Abstract]
Computed expected income tax provision	98,453	121,067	151,324
State income taxes, net of federal benefits	(1,246)	(20)	686
Research and development tax credits - current year	(13,542)	(9,703)	(4,875)
Research and development tax credits - prior years	(2,511)	(1,789)	1,600
Foreign income taxed at lower than the federal rate	(114,497)	(106,939)	(116,003)
Increases related to current and prior year tax positions	14,462	19,769	16,809
Decreases related to prior year tax positions (1)	(12,103)	(33,100)	(14,581)
Withholding taxes	5,970	5,218	6,212
Change in valuation allowance	(2,482)	(14,286)	0
Intercompany prepaid tax asset amortization	(15,493)	(1,089)	0
Other	357	1,454	(4,099)
Income tax provision	$ (42,632)	$ (19,418)	$ 37,073
Increase of basic net income per share due to release of prior year tax positions	$ 0.06	$ 0.16	$ 0.07
Increase of diluted net income per share due to release of prior year tax positions	$ 0.06	$ 0.15	$ 0.07
Income Tax Holiday, Aggregate Dollar Amount	$ 6,000	$ 12,400	$ 16,800
Undistributed Earnings of Foreign Subsidiaries	3,400,000
Tax Adjustments, Settlements, and Unusual Provisions	$ 12,100
Effective Income Tax Rate Reconciliation, Other Adjustments	4.30%

Components of deferred tax asse

Components of deferred tax assets and liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Income Tax Disclosure [Abstract]
Excess Tax Benefit from Share-based Compensation, Operating Activities	$ 758	$ 1,216	$ 1,411
Components of Deferred Tax Assets [Abstract]
Deferred intercompany profit	12,642	10,865
Deferred income on shipments to distributors	34,830	34,493
Inventory valuation	12,082	9,605
Net operating loss carryforward	63,209	105,756
Capital loss carryforward	5,707	4,582
Share-based compensation	31,410	26,780
Income tax credits	100,294	115,893
Property, plant and equipment, principally due to differences in depreciation	16,262	2,236
Accrued expenses and other	7,559	671
Gross deferred tax assets	283,995	310,881
Valuation allowances	(161,834)	(116,482)
Deferred tax assets, net of valuation allowances	122,161	194,399
Components of Deferred Tax Liabilities [Abstract]
Convertible debentures	(496,626)	(493,897)
Other	(9,922)	(10,649)
Deferred Tax Liabilities, Gross	506,548	504,546
Net deferred tax liability	(384,387)	(310,147)
Current deferred tax assets	0	71,045
Non-current deferred tax assets	14,831	0
Non-current deferred tax liability		$ (381,192)
Deferred Income Tax Liabilities, Net	(399,218)
Unrecorded Tax Benefits Related to Share-Based Compensation	$ 47,300

Operating loss carryforwards (D

Operating loss carryforwards (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Operating Loss Carryforwards [Line Items]
Capital loss carryforward	$ 5,707	$ 4,582
Capital loss carryforward, expiration date	Mar. 31, 2020
Capital loss carryforward, valuation allowance	$ 5,700
Foreign Tax Authority and Federal and State Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards	99,500
Operating Loss Carryforwards, Valuation Allowance	$ 53,200
Minimum | Foreign Tax Authority and Federal and State Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards, Expiration Date	Mar. 31, 2016
Maximum | Foreign Tax Authority and Federal and State Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards, Expiration Date	Mar. 31, 2035

Tax credit carryforward (Detail

Tax credit carryforward (Details) $ in Thousands	12 Months Ended
	Mar. 31, 2016USD ($)
Research Tax Credit Carryforward [Member]
Tax Credit Carryforward [Line Items]
Tax Credit Carryforward, Amount	$ 72,700
Research Tax Credit Carryforward [Member] | Minimum
Tax Credit Carryforward [Line Items]
Tax Credit Carryforward, Expiration Date	Mar. 31, 2022
Research Tax Credit Carryforward [Member] | Maximum
Tax Credit Carryforward [Line Items]
Tax Credit Carryforward, Expiration Date	Mar. 31, 2036
Alternative Minimum Tax [Member]
Tax Credit Carryforward [Line Items]
Tax Credit Carryforward, Amount	$ 4,300
Foreign Tax Authority [Member]
Tax Credit Carryforward [Line Items]
Tax Credit Carryforward, Amount	25,800
Tax Credit Carryforward, Valuation Allowance	$ 25,200
Foreign Tax Authority [Member] | Minimum
Tax Credit Carryforward [Line Items]
Tax Credit Carryforward, Expiration Date	Mar. 31, 2016
Foreign Tax Authority [Member] | Maximum
Tax Credit Carryforward [Line Items]
Tax Credit Carryforward, Expiration Date	Mar. 31, 2026
Foreign Tax Authority [Member] | Foreign Withholding Tax Credit [Member]
Tax Credit Carryforward [Line Items]
Tax Credit Carryforward, Amount	$ 20,000
Tax Credit Carryforward, Valuation Allowance	$ 20,000
Foreign Tax Authority [Member] | Foreign Withholding Tax Credit [Member] | Minimum
Tax Credit Carryforward [Line Items]
Tax Credit Carryforward, Expiration Date	Mar. 31, 2022
Foreign Tax Authority [Member] | Foreign Withholding Tax Credit [Member] | Maximum
Tax Credit Carryforward [Line Items]
Tax Credit Carryforward, Expiration Date	Mar. 31, 2024
State and Local Jurisdiction [Member]
Tax Credit Carryforward [Line Items]
Tax Credit Carryforward, Amount	$ 80,500
Tax Credit Carryforward, Valuation Allowance	$ 55,600
State and Local Jurisdiction [Member] | Minimum
Tax Credit Carryforward [Line Items]
Tax Credit Carryforward, Expiration Date	Mar. 31, 2016
State and Local Jurisdiction [Member] | Maximum
Tax Credit Carryforward [Line Items]
Tax Credit Carryforward, Expiration Date	Mar. 31, 2036

Unrecognized tax benefits (Deta

Unrecognized tax benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	$ 170,654	$ 149,878	$ 152,845
Increases related to acquisitions	46,245	8,381	341
Decreases related to settlements with tax authorities	(7,954)	(20,197)	(15,016)
Decreases related to statute of limitation expirations	(4,591)	(9,031)	(4,069)
Increases related to current year tax positions	16,315	23,179	14,669
Increases related to prior year tax positions	0	18,444	1,108
Ending balance	220,669	170,654	149,878
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued [Abstract]
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	2,400	700
Unrecognized Tax Benefits, Income Tax Penalties Accrued	27,600
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	1,700	$ (1,800)	$ 200
Increase in unrecognized tax benefits related to prior year tax positions balance sheet reclassification	$ 15,700

1.625% Senior Subordinated Co84

1.625% Senior Subordinated Convertible Debentures (Details)	12 Months Ended
	Mar. 31, 2016USD ($)$ / shares	Mar. 31, 2015USD ($)	Mar. 31, 2014USD ($)
Debt Instrument [Line Items]
Amortization of debt discount on convertible debentures	$ 48,022,000	$ 14,791,000	$ 8,970,000
Senior Subordinated Convertible Debenture Due 2025 [Member]
Debt Instrument [Line Items]
Principal amount of senior subordinated convertible debentures	$ 1,725,000,000
Interest rate of senior subordinated convertible debentures	1.625%
Due date of senior subordinated convertible debentures	Feb. 15, 2025
Conversion rate, in shares, of senior subordinated convertible debt (in shares per $1,000)	14.5654
Principal amount of senior subordinated convertible debentures used as conversion unit	$ 1,000
Convertible Debt Instrument Initial Conversion Price Per Share | $ / shares	$ 68.66
Debt Instrument, Convertible, Conversion Ratio	15.1396
Debt Instrument, Convertible, Conversion Price | $ / shares	$ 66.05
Debt instrument, Convertible, Conversion Ratio Increase Option, Initial Ratio at Issuance	7.2827
Debt Instrument, Convertible, Conversion Ratio Increase Option, Adjusted for Dividends	7.5698
Debt Instrument, Convertible, Conversion Ratio Maximum Conversion Rate including increase Option	20.3915
Debt Instrument, Convertible, Conversion Ratio Maximum Conversion Rate including increase option, adjusted for dividends paid	21.1954
Proceeds from issuance of senior subordinated convertible debentures, net of issuance costs	$ 1,694,700,000
Senior subordinated convertible debenture debt issuance costs	30,300,000
Debt portion of convertible debt issuance costs	20,400,000
Equity portion of convertible debt issuance costs	9,900,000
Carrying value of equity component of the senior subordinated convertible debentures that were bifurcated into a liability and equity component	564,900,000	564,900,000
Estimated fair value of the liability component of the senior subordinated convertible debentures as of the issuance date	1,160,100,000
Debt discount of estimated fair value of liability component of senior subordinated convertible debentures at the issuance date	564,900,000
Amount of unamortized debt discount of debentures	$ 490,300,000	559,300,000
Remaining period, in years, over which unamortized debt discount will be recognized as non-cash interest expense (in years)	8 years 10 months 15 days
Amortization of debt discount on convertible debentures	$ 42,600,000	5,700,000
Recognized amount of interest expense related to coupon on senior subordinated convertible debentures	$ 28,000,000	$ 3,800,000
Effective interest rate of senior convertible debentures	5.90%

2.125% Junior subordinated co85

2.125% Junior subordinated convertible debentures (Details)	12 Months Ended
	Mar. 31, 2016USD ($)$ / shares	Mar. 31, 2015USD ($)	Mar. 31, 2014USD ($)	Mar. 31, 2013USD ($)
Debt Instrument [Line Items]
Payment to retire $575 million aggregate principal amount of junior convertible debentures	$ 0	$ 1,134,621,000	$ 0
Loss on retirement of junior convertible debentures	0	50,631,000	0
Carrying value of debentures	196,304,000	190,870,000
Amortization of Debt Discount (Premium)	48,022,000	14,791,000	8,970,000
Junior subordinated convertible debentures due 2037 [Member]
Debt Instrument [Line Items]
Payment to retire $575 million aggregate principal amount of junior convertible debentures		1,134,600,000
Liability portion of payment made to retire $575 million aggregate principal amount of junior convertible debentures		238,300,000
Equity portion of payment made to retire $575 million aggregate principal amount of junior convertible debentures		896,300,000
Principal amount of junior subordinated convertible debentures	$ 575,000,000	575,000,000
Interest rate of junior subordinated convertible debentures	2.125%
Due date of junior subordinated convertible debentures	Dec. 15, 2037
Conversion rate, in shares, of junior subordinated convertible debt (in shares per $1,000)	29.2783
Principal amount of junior subordinated convertible debentures used as conversion unit	$ 1,000
Convertible Debt Instrument Initial Conversion Price Per Share | $ / shares	$ 34.16
Debt Instrument, Convertible, Conversion Ratio	41.1350
Debt Instrument, Convertible, Conversion Price | $ / shares	$ 24.31
Debt Instrument, Convertible, If-converted Value in Excess of Principal	$ 565,100,000
Contingent interest rate	0.50%
Carrying value of equity component of the junior subordinated convertible debentures that were bifurcated into a liability and equity component	$ 411,200,000	411,200,000
Estimated fair value of the liability component of the junior subordinated convertible debentures as of the issuance date	163,800,000
Debt discount of estimated fair value of liability component of junior subordinated convertible debentures at the issuance date	411,200,000
Amount of unamortized debt discount of debentures	$ 378,300,000	383,700,000
Remaining period, in years, over which unamortized debt discount will be recognized as non-cash interest expense (in years)	21 years 9 months
Amortization of Debt Discount (Premium)	$ 5,400,000	9,100,000	$ 9,000,000
Recognized amount of interest expense related to coupon on junior subordinated convertible debentures	$ 12,200,000	$ 22,800,000		$ 24,400,000
Effective interest rate of junior convertible debentures	9.10%
Junior subordinated convertible debentures due 2037 [Member] | Minimum
Debt Instrument [Line Items]
Contingent interest rate	0.25%
Debenture trading price | $ / shares	$ 400
Junior subordinated convertible debentures due 2037 [Member] | Maximum
Debt Instrument [Line Items]
Contingent interest rate	0.50%
Debenture trading price | $ / shares	$ 1,500

Credit facility (Details)

Credit facility (Details)	12 Months Ended
	Mar. 31, 2016USD ($)	Mar. 31, 2015USD ($)	Mar. 31, 2014USD ($)	Feb. 04, 2015USD ($)	Jun. 27, 2013USD ($)
Line of Credit Facility [Line Items]
Interest Expense	$ 104,018,000	$ 62,034,000	$ 48,716,000
Credit Agreement Maturity June 27, 2018 [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity					$ 2,000,000,000
February 2015 Amended Credit Facility with Maturity Dates of June 2018 and February 2020 [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity				$ 2,555,000,000
Line of Credit Facility Increase Option				$ 249,400,000	$ 300,000,000
Debt Instrument, Description of Variable Rate Basis	the highest of JPMorgan Chase Bank, N.A.'s prime rate, the federal funds rate plus a margin equal to 0.50% and the adjusted LIBOR rate for a 1-month interest period plus a margin equal to 1.00%
Interest Expense	$ 18,900,000	19,900,000	$ 14,600,000
Short-term Debt, Weighted Average Interest Rate	1.94%
February 2015 Amended Credit Facility with Maturity Dates of June 2018 and February 2020 [Member] | Line of Credit [Member]
Line of Credit Facility [Line Items]
Period For Leverage Ratio To Determine Interest Rate Spread	preceding four fiscal quarters
Debt Instrument Interest Rate Spread On Overdue Principal In Event Of Default				2.00%
Debt Instrument Interest Rate Spread On Overdue Amounts In Event Of Default				2.00%
February 2015 Amended Credit Facility with Maturity Dates of June 2018 and February 2020 [Member] | Line of Credit [Member] | Debt Instrument Interest Rate Option1 [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.25%
February 2015 Amended Credit Facility with Maturity Dates of June 2018 and February 2020 [Member] | Line of Credit [Member] | Debt Instrument Interest Rate Option1 [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.25%
February 2015 Amended Credit Facility with Maturity Dates of June 2018 and February 2020 [Member] | Line of Credit [Member] | Debt Instrument Interest Rate Option 2 [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Description of Variable Rate Basis	adjusted LIBOR rate (based on one, two, three, or six-month interest periods)
February 2015 Amended Credit Facility with Maturity Dates of June 2018 and February 2020 [Member] | Line of Credit [Member] | Debt Instrument Interest Rate Option 2 [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.25%
February 2015 Amended Credit Facility with Maturity Dates of June 2018 and February 2020 [Member] | Line of Credit [Member] | Debt Instrument Interest Rate Option 2 [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.25%
February 2015 Amended Credit Facility with Maturity Dates of June 2018 and February 2020 [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Amount Outstanding	$ 1,052,000,000	$ 462,000,000
February 2015 Amended Credit Facility with Maturity Dates of June 2018 and February 2020 [Member] | Foreign Line of Credit [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity				$ 125,000,000
February 2015 Amended Credit Facility with Maturity Dates of June 2018 and February 2020 [Member] | Standby Letters of Credit [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity				25,000,000
February 2015 Amended Credit Facility with Maturity Dates of June 2018 and February 2020 [Member] | Line of Credit Facility Swingline Loan Sublimit [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity				$ 25,000,000
December 2015 Amended Credit Facility with Maturity Dates of June 2018 and February 2020 [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	2,774,000,000
Remaining Increase Option Amount	30,400,000
Line of Credit Facility Increase Option	$ 219,000,000
Credit Agreement, Total Leverage Ratio, Temporary Maximum Allowed, First Four Quarters	5
Credit Agreement, Total Leverage Ratio, Temporary Maximum Allowed, Next Three Quarters	4.75
Credit Agreement, Total Leverage Ratio, Maximum	4.50

Contingencies (Details)

Contingencies (Details) $ in Millions	Mar. 31, 2016USD ($)
Indemnification agreement [Member]
Loss contingencies [Line Items]
Loss contingencies, estimate of possible loss	$ 143

Stock Repurchase Activity (Deta

Stock Repurchase Activity (Details) - USD ($) $ in Thousands	12 Months Ended	88 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Jan. 18, 2016	May. 15, 2015	Dec. 11, 2007
Equity [Abstract]
Stock Repurchase Program, Number of Shares Authorized to be Repurchased			15,000,000	20,000,000	10,000,000
Repurchased shares under authorization (in shares)	8,600,000	7,500,000
Amount of repurchased shares under authorization	$ 363,829	$ 234,700
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased				11,400,000	2,500,000

Employee Benefit Plans (Details

Employee Benefit Plans (Details) - USD ($) $ in Millions

Jan. 01, 2016

Jan. 01, 2015

Jan. 01, 2014

May. 01, 2006

Jan. 01, 2005

Mar. 01, 2002

Mar. 31, 2016

Mar. 31, 2015

Mar. 31, 2014

Mar. 31, 1995

Mar. 31, 2016

Mar. 31, 2016

Overlapping Stock Purchase Period 1 [Member]

Deferred compensation arrangement, by type of deferred compensation [Line Items]

Overlapping period on purchase of common stock under purchase plan (in number of months)

24 months

Overlapping Stock Purchase Period 2 [Member]

Deferred compensation arrangement, by type of deferred compensation [Line Items]

Overlapping period on purchase of common stock under purchase plan (in number of months)

18 months

Overlapping Stock Purchase Period 3 [Member]

Deferred compensation arrangement, by type of deferred compensation [Line Items]

Overlapping period on purchase of common stock under purchase plan (in number of months)

12 months

Overlapping Stock Purchase Period 4 [Member]

Deferred compensation arrangement, by type of deferred compensation [Line Items]

Overlapping period on purchase of common stock under purchase plan (in number of months)

6 months

Defined contribution pension [Member]

Deferred compensation arrangement, by type of deferred compensation [Line Items]

Percentage of employee's base salary allowed as employee contribution (in hundredths)

60.00%

60.00%

60.00%

Amount of company contributions

$ 4.4

$ 3.9

$ 3.6

Employee stock purchase plan, 2001 plan [Member]

Deferred compensation arrangement, by type of deferred compensation [Line Items]

Percentage of fair market value of common stock for employee purchase (in hundredths)

85.00%

Number of additional shares reserved under purchase plan (in shares)

1,017,492

0

0

Number of shares of common stock reserved for issuance (in shares)

12,295,354

12,295,354

12,295,354

Shares issued under purchase plan (in shares)

6,651,710

Employee stock purchase plan, employees in non-US locations [Member]

Deferred compensation arrangement, by type of deferred compensation [Line Items]

Percentage of fair market value of common stock for employee purchase (in hundredths)

85.00%

Number of additional shares reserved under purchase plan (in shares)

203,498

0

0

Number of shares of common stock reserved for issuance (in shares)

1,703,783

1,703,783

1,703,783

Shares issued under purchase plan (in shares)

1,063,360

Percentage of fair market value of common stock at the beginning or end of semi-annual purchase plan period, during fiscal 1995 (in hundredths)

100.00%

Supplemental Employee Retirement Plans, Defined Benefit [Member]

Deferred compensation arrangement, by type of deferred compensation [Line Items]

Defined Benefit Plan, Benefit Obligation

$ 5.2

$ 5.2

$ 5.2

Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months

0.7

0.7

0.7

Defined Benefit Plan, Expected Future Benefit Payments, Year Two Through Year Ten

3.8

$ 3.8

$ 3.8

Management incentive compensation plan [Member]

Deferred compensation arrangement, by type of deferred compensation [Line Items]

Compensation expense charged against operations

19.1

24.2

24.4

Cash bonus plan [Member]

Deferred compensation arrangement, by type of deferred compensation [Line Items]

Compensation expense charged against operations

$ 14.2

$ 15.9

$ 15.2

Maximum | Employee stock purchase plan, 2001 plan [Member]

Deferred compensation arrangement, by type of deferred compensation [Line Items]

Maximum automatic increase in number of common stock shares under purchase plan (in shares)

1,500,000

Percentage of outstanding shares of common stock used to determine automatic annual increase in common stock (in hundredths)

0.50%

Equity Incentive Plans, Stock C

Equity Incentive Plans, Stock Compensation Expensed (Details) - USD ($) $ in Thousands		12 Months Ended
		Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Stock-based compensation expense [Line Items]
Share based compensation expense		$ 71,420	$ 58,596	$ 53,787
Income tax benefit		23,012	10,640	5,722
Net income effect of share-based compensation		48,408	47,956	48,065
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized		$ 134,500
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition		2 years 3 months 20 days
Inventory [Member]
Stock-based compensation expense [Line Items]
Amount of share-based compensation expense capitalized to inventory		$ 7,900	6,800	7,400
Cost of sales
Stock-based compensation expense [Line Items]
Share based compensation expense	[1]	8,252	9,010	7,340
Research and development [Member]
Stock-based compensation expense [Line Items]
Share based compensation expense		32,022	28,164	24,554
Selling, general and administrative [Member]
Stock-based compensation expense [Line Items]
Share based compensation expense		$ 31,146	$ 21,422	$ 21,893
[1]	During the year ended March 31, 2016, $7.9 million of share-based compensation expense was capitalized to inventory, and $8.3 million of previously capitalized share-based compensation expense in inventory was sold. During the year ended March 31, 2015, $6.8 million of share-based compensation expense was capitalized to inventory, and $9.0 million of previously capitalized share-based compensation expense in inventory was sold. During the year ended March 31, 2014, $7.4 million of share-based compensation expense was capitalized to inventory, and $7.3 million of previously capitalized share-based compensation expense in inventory was sold.

Equity Incentive Plans, Share-b

Equity Incentive Plans, Share-based Payment Award (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
RSU nonvested shares beginning balance	5,268,916	5,530,034	6,009,831
RSU shares granted	2,479,729	1,446,968	1,616,632
RSU shares assumed upon acquisition	525,442
RSU shares forfeited/expired	(360,072)	(266,415)	(282,964)
RSU shares vested	(1,606,273)	(1,441,671)	(1,813,465)
RSU nonvested shares ending balance	6,307,742	5,268,916	5,530,034
Closing price of company's common stock related to calculation of aggregate intrinsic value of stock options (in dollars per share)	$ 48.20
Restricted stock units' weighted average remaining expense recognition period (in years)	2 years 3 months 20 days
Restricted stock units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Total intrinsic value of RSU's vested during the period	$ 72.1	$ 67.6	$ 74.6
Total intrinsic value of RSU's outstanding	$ 304
Restricted stock units' weighted average remaining expense recognition period (in years)	2 years 4 months 6 days
Weighted average fair values per share of restricted stock units awarded (amount per share)	$ 38.92	$ 42.02	$ 34.24

Equity Incentive Plans, Stock O

Equity Incentive Plans, Stock Options Outstanding (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Option shares outstanding beginning balance (in shares)	684,299	573,611	2,269,803
Options granted (in shares)	244	27,654	0
Options assumed upon acquisition (in shares)	604,900	666,586
Options exercised (shares)	(221,987)	(477,618)	(1,675,663)
Options canceled (in shares)	(153,948)	(105,934)	(20,529)
Option shares outstanding ending balance (in shares)	913,508	684,299	573,611
Option shares outstanding beginning balance (in dollars per share)	$ 28.41	$ 24.75	$ 25.58
Options granted (in dollars per shares)	41.09	46.66	0
Options assumed upon acquisition (in dollars per share)	35.03	29.33
Options exercised (in dollars per share)	25.30	26.42	25.91
Options canceled (in dollars per share)	31.52	28.17	22.78
Option shares outstanding ending balance (in dollars per share)	33	$ 28.41	$ 24.75
Closing price of company's common stock related to calculation of aggregate intrinsic value of stock options (in dollars per share)	$ 48.20
Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Total intrinsic value of options exercised related to stock incentive plans	$ 4.7	$ 9.6	$ 25.5
Aggregate intrinsic value of options outstanding related to stock incentive plans	13.9
Aggregate intrinsic value of options exercisable related to stock incentive plans	$ 8.8
Exercisable number of option shares (in shares)	553,844	283,133
Weighted average exercise price per share of exercisable options (in dollars per share)	$ 32.33	$ 26.90
Weighted average fair value per share of stock options granted	$ 8.85	$ 9

Equity Incentive Plans Valuatio

Equity Incentive Plans Valuation of Stock Options Granted (Details) - Stock Option [Member]	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	6 years 6 months	6 years 6 months
Volatility	29.50%	26.65%
Risk-free interest rate	1.54%	1.59%
Dividend yield	3.00%	3.00%

Commitments (Details)

Commitments (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Future minimum lease commitments under operating leases [Abstract]
Operating Leases, Future Minimum Payments Due, Current	$ 16,370
Operating Leases, Future Minimum Payments, Due in Two Years	12,350
Operating Leases, Future Minimum Payments, Due in Three Years	7,677
Operating Leases, Future Minimum Payments, Due in Four Years	3,098
Operating Leases, Future Minimum Payments, Due in Five Years	1,000
Operating Leases, Future Minimum Payments, Due Thereafter	667
Operating Leases, Total Future Minimum Payments Due	41,162
Rental expense under operating lease	23,300	$ 23,800	$ 21,500
Property, Plant and Equipment Purchase Commitment [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Purchase Commitment, Remaining Minimum Amount Committed	30,200
Purchase Commitment, Other Obligations [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Purchase Commitment, Remaining Minimum Amount Committed	57,600
Wafer Foundry Purchase Commitment [Member]
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Purchase Commitment, Remaining Minimum Amount Committed	$ 52,400

Geographic and Segment Inform95

Geographic and Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Segment Reporting Information [Line Items]
Segment Net Sales	$ 557,647	$ 540,344	$ 541,391	$ 533,952	$ 543,207	$ 528,710	$ 546,243	$ 528,876	$ 2,173,334	$ 2,147,036	$ 1,931,217
Segment Gross Profit	$ 302,779	$ 292,718	$ 300,950	$ 309,017	$ 313,632	$ 301,959	$ 307,454	$ 306,519	1,205,464	1,229,564	1,128,743
Semiconductor products [Member]
Segment Reporting Information [Line Items]
Segment Net Sales									2,084,210	2,057,443	1,836,639
Segment Gross Profit									1,116,340	1,139,971	1,034,165
Technology licensing [Member]
Segment Reporting Information [Line Items]
Segment Net Sales									89,124	89,593	94,578
Segment Gross Profit									$ 89,124	$ 89,593	$ 94,578

Revenue and Assets by Geographi

Revenue and Assets by Geographic Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Segment Reporting Information [Line Items]
Amount of identifiable long-lived assets (consisting of property, plant and equipment)	$ 609,396	$ 581,572
United States [Member]
Segment Reporting Information [Line Items]
Amount of identifiable long-lived assets (consisting of property, plant and equipment)	373,860	331,372
Thailand [Member]
Segment Reporting Information [Line Items]
Amount of identifiable long-lived assets (consisting of property, plant and equipment)	182,813	197,981
Various Other Countries besides United States and Thailand [Member]
Segment Reporting Information [Line Items]
Amount of identifiable long-lived assets (consisting of property, plant and equipment)	$ 52,723	$ 52,219
Located outside US, in aggregate [Member]
Geographic Areas, Revenues from External Customers [Abstract]
Percentage of net sales to unaffiliated customers	84.00%	84.00%	84.00%
Europe [Member]
Geographic Areas, Revenues from External Customers [Abstract]
Percentage of net sales to unaffiliated customers	22.00%	21.00%	21.00%
Asia [Member]
Geographic Areas, Revenues from External Customers [Abstract]
Percentage of net sales to unaffiliated customers	59.00%	59.00%	60.00%
China, including Hong-Kong [Member]
Geographic Areas, Revenues from External Customers [Abstract]
Percentage of net sales to unaffiliated customers	30.00%	28.00%	29.00%
Taiwan [Member]
Geographic Areas, Revenues from External Customers [Abstract]
Percentage of net sales to unaffiliated customers	12.00%	14.00%	13.00%

Freestanding Derivative Forward

Freestanding Derivative Forward Contracts (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Derivative [Line Items]
Percentage Of Company Sales Denominated In Us Dollars	99.00%
Foreign Currency Transaction Gain (Loss), before Tax	$ 0.7	$ (7.7)	$ 0.4

Derivative Instruments Fair Val

Derivative Instruments Fair Value (Details) - Interest Rate Swap [Member] - Designated as Hedging Instrument [Member] - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Derivatives, Fair Value [Line Items]
Derivative Asset, Notional Amount		$ 431,300
Cash receipts upon termination of interest rate swap agreements	$ 25,700
Other Noncurrent Assets [Member]
Derivatives, Fair Value [Line Items]
Interest Rate Contracts		$ 8,928

Derivative Instruments Gain (Lo

Derivative Instruments Gain (Loss) (Details) - Interest Rate Swap [Member] - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Derivative [Line Items]
Gain (Loss) on Senior Subordinated Convertible Debentures	$ (18,060)	$ (8,302)
Gain (Loss) on Interest Rate Swap	$ 16,345	$ 8,928

Net income per common share 100

Net income per common share attributable to Microchip Technology Stockholders (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income attributable to Microchip Technology	$ 67,355	$ 61,211	$ 64,899	$ 130,667	$ 99,402	$ 86,057	$ 93,641	$ 89,909	$ 324,132	$ 369,009	$ 395,281
Weighted average common shares outstanding									203,384,000	200,937,000	198,291,000
Dilutive effect of stock options and RSUs									3,350,000	3,642,000	3,910,000
Dilutive effect of 2037 junior subordinated convertible debentures									10,654,070	18,982,440	15,429,003
Weighted average common and potential common shares outstanding									217,388,000	223,561,000	217,630,000
Basic net income per common share attributable to Microchip Technology stockholders									$ 1.59	$ 1.84	$ 1.99
Diluted net income per common share attributable to Microchip Technology stockholders	$ 0.31	$ 0.28	$ 0.30	$ 0.60	$ 0.45	$ 0.39	$ 0.42	$ 0.40	$ 1.49	$ 1.65	$ 1.82
Number of antidilutive option shares (in shares)									298,015	19,305	0
Junior Subordinated Convertible Debentures Due2037 Member
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Weighted Average Conversion Price Per Share Used In Calculating Dilutive Effect Of Convertible Debt Amount Per Share									$ 24.73	$ 25.48	$ 26.32
Senior Subordinated Convertible Debenture Due 2025 [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Weighted Average Conversion Price Per Share Used In Calculating Dilutive Effect Of Convertible Debt Amount Per Share									$ 67.19	$ 68.25

Quarterly Results (Unaudited101

Quarterly Results (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 557,647	$ 540,344	$ 541,391	$ 533,952	$ 543,207	$ 528,710	$ 546,243	$ 528,876	$ 2,173,334	$ 2,147,036	$ 1,931,217
Gross profit	302,779	292,718	300,950	309,017	313,632	301,959	307,454	306,519	1,205,464	1,229,564	1,128,743
Operating income	79,946	76,132	74,948	121,319	110,347	98,009	101,318	115,946	352,345	425,620	458,864
Net income	67,355	61,211	64,899	130,460	98,580	84,798	92,038	89,909	323,925	365,325	395,281
Less: Net loss attributable to noncontrolling interests	0	0	0	207	822	1,259	1,603	0	207	3,684	0
Net income attributable to Microchip Technology	$ 67,355	$ 61,211	$ 64,899	$ 130,667	$ 99,402	$ 86,057	$ 93,641	$ 89,909	$ 324,132	$ 369,009	$ 395,281
Diluted net income per common share attributable to Microchip Technology stockholders	$ 0.31	$ 0.28	$ 0.30	$ 0.60	$ 0.45	$ 0.39	$ 0.42	$ 0.40	$ 1.49	$ 1.65	$ 1.82
Loss on retirement of junior convertible debentures									$ 0	$ 50,631	$ 0

Supplemental Financial Infor102

Supplemental Financial Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Supplemental Cash Flow Information [Abstract]
Cash paid for income taxes	$ 25,400	$ 25,500	$ 25,700
Cash paid for interest on borrowings	52,900	40,200	34,600
Allowance for Doubtful Accounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balances at Beginning of Year	2,621	2,918	2,764
Charged to Cost and Expense	59	104	245
Deductions	(140)	(401)	(91)
Balance at End of Year	2,540	2,621	2,918
Valuation Allowance of Deferred Tax Assets [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balances at Beginning of Year	116,482	93,811	88,637
Charged to Cost and Expense	5,535	0	0
Charged to Other Accounts	47,834	36,957	5,174
Deductions	(8,017)	(14,286)	0
Balance at End of Year	$ 161,834	$ 116,482	$ 93,811

Comprehensive Income (Schedule

Comprehensive Income (Schedule of Changes in the Components of AOCI) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance	$ 11,076	$ 1,051
Other comprehensive income (loss) before reclassifications	(3,210)	29,310
Amounts reclassified from accumulated other comprehensive income (loss)	(10,948)	(18,694)
Net other comprehensive income (loss)	(14,158)	10,616	$ (5,884)
Purchase of shares from noncontrolling interest	(275)	(591)
Balance	(3,357)	11,076	1,051
Accumulated Net Unrealized Investment Gain (Loss) [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance	14,537	(528)
Other comprehensive income (loss) before reclassifications	(3,241)	33,759
Amounts reclassified from accumulated other comprehensive income (loss)	(10,948)	(18,694)
Net other comprehensive income (loss)	(14,189)	15,065
Purchase of shares from noncontrolling interest	0	0
Balance	348	14,537	(528)
Accumulated Defined Benefit Plans Adjustment [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance	13	140
Other comprehensive income (loss) before reclassifications	31	(127)
Amounts reclassified from accumulated other comprehensive income (loss)	0	0
Net other comprehensive income (loss)	31	(127)
Purchase of shares from noncontrolling interest	0	0
Balance	44	13	140
Accumulated Translation Adjustment [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance	(3,474)	1,439
Other comprehensive income (loss) before reclassifications	0	(4,322)
Amounts reclassified from accumulated other comprehensive income (loss)	0	0
Net other comprehensive income (loss)	0	(4,322)
Purchase of shares from noncontrolling interest	(275)	(591)
Balance	$ (3,749)	$ (3,474)	$ 1,439

Comprehensive Income (Schedu104

Comprehensive Income (Schedule Of Reclassifications Of Recognized Transactions Out Of AOCI) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other income, net									$ 8,864	$ 13,742	$ 5,898
Income tax provision									42,632	19,418	(37,073)
Net income attributable to Microchip Technology	$ 67,355	$ 61,211	$ 64,899	$ 130,667	$ 99,402	$ 86,057	$ 93,641	$ 89,909	324,132	369,009	395,281
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other income, net									10,948	18,706	2,371
Income tax provision									0	(12)	(776)
Net income attributable to Microchip Technology									$ 10,948	$ 18,694	$ 1,595

Dividends (Details)

Dividends (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Dividends [Abstract]
Total dividends per share for the period	$ 1.433	$ 1.425	$ 1.417
Total dividend payments	$ 291,087	$ 286,478	$ 281,204

Subsequent Events Business Acqu

Subsequent Events Business Acquisitions (Narrative) (Details) - USD ($) $ in Thousands, shares in Millions	Apr. 04, 2016	Mar. 31, 2016
Subsequent Event [Line Items]
Non cash consideration transferred in the form of share-based payment awards (amount)		$ 4,052
Subsequent Event [Member] | Atmel Corporation [Member]
Subsequent Event [Line Items]
Payments to Acquire Businesses, Gross	$ 2,980,000
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares	10.1
Non cash consideration transferred in the form of share-based payment awards (amount)	$ 6,700
Business Combination, Consideration Transferred	3,470,000
Payments to Acquire Businesses, less portion funded from Line of Credit Borrowings	2,040,000
Proceeds from Lines of Credit	940,000
Deferred Tax Liabilities, Intangible Assets	$ 143,200

NOTE 28 SUBSEQUENT EVENTS Subse

NOTE 28 SUBSEQUENT EVENTS Subsequent Events Business Acquisitions (Schedule of Purchase Price Allocation) (Details) - USD ($) $ in Thousands	Apr. 04, 2016	Mar. 31, 2016	Mar. 31, 2015
Subsequent Event [Line Items]
Goodwill		$ 1,012,652	$ 571,271
Subsequent Event [Member] | Atmel Corporation [Member]
Subsequent Event [Line Items]
Cash and cash equivalents	$ 210,252
Accounts receivable, net	195,481
Inventories	403,708
Prepaid expenses and other current assets	35,299
Property, plant and equipment, net	131,154
Goodwill	1,400,814
Purchased intangible assets	1,551,100
Long-term deferred tax assets	157,929
Other assets	45,747
Total assets acquired	4,131,484
Accounts payable	(59,470)
Other current liabilities	(133,012)
Long-term line of credit	(192,300)
Deferred tax liability	(155,553)
Long-term income tax payable	(49,965)
Other long-term liabilities	(67,577)
Total liabilities assumed	657,877
Purchase price allocated	$ 3,473,607

NOTE 28 SUBSEQUENT EVENTS Su108

NOTE 28 SUBSEQUENT EVENTS Subsequent Events Business Acquisitions (Schedule of Purchased Intangible Assets) (Details) - USD ($) $ in Thousands	Apr. 04, 2016	Mar. 31, 2016
Core/developed technology
Subsequent Event [Line Items]
Acquired Finite-lived Intangible Asset, Amount		$ 175,800
In-process technology
Subsequent Event [Line Items]
Acquired Finite-lived Intangible Asset, Amount		21,000
Backlog
Subsequent Event [Line Items]
Acquired Finite-lived Intangible Asset, Amount		$ 5,600
Subsequent Event [Member] | Atmel Corporation [Member]
Subsequent Event [Line Items]
Acquired Finite-lived Intangible Asset, Amount	$ 1,551,100
Subsequent Event [Member] | Atmel Corporation [Member] | Core/developed technology
Subsequent Event [Line Items]
Acquired Finite-lived Intangible Asset, Amount	988,400
Subsequent Event [Member] | Atmel Corporation [Member] | In-process technology
Subsequent Event [Line Items]
Acquired Finite-lived Intangible Asset, Amount	$ 114,500
Subsequent Event [Member] | Atmel Corporation [Member] | Customer-related
Subsequent Event [Line Items]
Finite-Lived Intangible Asset, Useful Life	5 years
Acquired Finite-lived Intangible Asset, Amount	$ 435,900
Subsequent Event [Member] | Atmel Corporation [Member] | Backlog
Subsequent Event [Line Items]
Acquired Finite-lived Intangible Asset, Amount	$ 12,300
Minimum [Member]
Subsequent Event [Line Items]
Finite-Lived Intangible Asset, Useful Life		1 year
Minimum [Member] | Subsequent Event [Member] | Atmel Corporation [Member] | Core/developed technology
Subsequent Event [Line Items]
Finite-Lived Intangible Asset, Useful Life	10 years
Minimum [Member] | Subsequent Event [Member] | Atmel Corporation [Member] | In-process technology
Subsequent Event [Line Items]
Finite-Lived Intangible Asset, Useful Life	10 years
Minimum [Member] | Subsequent Event [Member] | Atmel Corporation [Member] | Backlog
Subsequent Event [Line Items]
Finite-Lived Intangible Asset, Useful Life	1 year
Maximum [Member]
Subsequent Event [Line Items]
Finite-Lived Intangible Asset, Useful Life		15 years
Maximum [Member] | Subsequent Event [Member] | Atmel Corporation [Member] | Core/developed technology
Subsequent Event [Line Items]
Finite-Lived Intangible Asset, Useful Life	15 years
Maximum [Member] | Subsequent Event [Member] | Atmel Corporation [Member] | In-process technology
Subsequent Event [Line Items]
Finite-Lived Intangible Asset, Useful Life	15 years
Maximum [Member] | Subsequent Event [Member] | Atmel Corporation [Member] | Backlog
Subsequent Event [Line Items]
Finite-Lived Intangible Asset, Useful Life	2 years

NOTE 28 SUBSEQUENT EVENTS Su109

NOTE 28 SUBSEQUENT EVENTS Subsequent Events Business Acquisitions (Pro Forma Information) (Details) - Atmel Corporation [Member] - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Subsequent Event [Line Items]
Net sales	$ 3,345,790	$ 3,560,370
Net income	$ 167,705	$ 116,618
Basic earnings per share	$ 0.79	$ 0.55
Diluted earnings per share	$ 0.74	$ 0.50