Microchip Technology (MCHP) 10-Q 8 Nov 16 2017 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information Document - shares	6 Months Ended
	Sep. 30, 2016	Oct. 31, 2016
DEI 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-Q
Document Period End Date	Sep. 30, 2016
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Common Stock, Shares Outstanding		216,016,163

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (unaudited) - USD ($) $ in Thousands	Sep. 30, 2016	Mar. 31, 2016
ASSETS
Cash and cash equivalents	$ 489,988	$ 2,092,751
Short-term investments	848	353,284
Accounts receivable, net	451,042	290,183
Inventories	424,690	306,815
Prepaid expenses	60,817	41,992
Assets held for sale	14,080	0
Other current assets	49,270	11,688
Total current assets	1,490,735	3,096,713
Property, plant and equipment, net	716,998	609,396
Long-term investments	0	118,549
Goodwill	2,384,740	1,012,652
Intangible assets, net	2,322,706	606,349
Long-term deferred tax assets	68,823	14,831
Other assets	90,394	79,393
Total assets	7,074,396	5,537,883
LIABILITIES AND STOCKHOLDERS' EQUITY
Accounts payable	131,625	79,312
Accrued liabilities	223,982	119,265
Deferred income on shipments to distributors	223,196	183,432
Total current liabilities	578,803	382,009
Long-term line of credit	1,669,834	1,043,156
Senior convertible debentures	1,238,731	1,216,313
Junior convertible debentures	196,868	193,936
Long-term income tax payable	292,957	111,061
Long-term deferred tax liability	416,452	399,218
Other long-term liabilities	161,239	41,271
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; 237,465,809 shares issued and 215,954,392 shares outstanding at September 30, 2016; 227,416,789 shares issued and 204,081,727 shares outstanding at March 31, 2016	216	204
Additional paid-in capital	1,905,228	1,391,553
Common stock held in treasury: 21,511,417 shares at September 30, 2016; 23,335,062 shares at March 31, 2016	(765,904)	(820,066)
Accumulated other comprehensive loss	(15,896)	(3,357)
Retained earnings	1,395,868	1,582,585
Total stockholders' equity	2,519,512	2,150,919
Total liabilities and stockholders' equity	$ 7,074,396	$ 5,537,883

CONDENSED CONSOLIDATED BALANCE3

CONDENSED CONSOLIDATED BALANCE SHEETS CONDENSED CONSOLIDATED BALANCE SHEETS (PARENTHETICAL) - $ / shares	Sep. 30, 2016	Mar. 31, 2016
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 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
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	450,000,000	450,000,000
Common stock, shares issued	237,465,809	227,416,789
Common stock, shares outstanding	215,954,392	204,081,727
Common stock held in treasury	21,511,417	23,335,062

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (unaudited) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Statement [Abstract]
Net sales		$ 871,364	$ 541,391	$ 1,670,775	$ 1,075,343
Cost of sales (1)	[1]	460,743	240,441	911,664	465,376
Gross profit		410,621	300,950	759,111	609,967
Research and development (1)	[1]	137,795	95,256	285,678	179,936
Selling, general and administrative (1)	[1]	120,129	80,258	277,634	147,107
Amortization of acquired intangible assets		80,394	43,840	160,565	78,452
Special charges, net		9,543	6,648	31,578	8,205
Operating expenses		347,861	226,002	755,455	413,700
Operating income		62,760	74,948	3,656	196,267
Losses on equity method investments		(56)	(56)	(112)	(233)
Other income (expense):
Interest income		445	6,405	1,264	11,933
Interest expense		(35,126)	(25,644)	(69,542)	(49,696)
Other (loss) income, net		(2,789)	(1,696)	(779)	15,251
Income (loss) before income taxes		25,234	53,957	(65,513)	173,522
Income tax (benefit) provision		(10,340)	(10,942)	8,138	(21,837)
Net income (loss) from continuing operations		35,574	64,899	(73,651)	195,359
Loss from discontinued operations		(1,850)	0	(7,323)	0
Income tax benefit		(195)	0	(1,530)	0
Net loss from discontinued operations		(1,655)	0	(5,793)	0
Net income (loss)		33,919	64,899	(79,444)	195,359
Less: Net loss attributable to noncontrolling interests		0	0	0	207
Net income (loss) attributable to Microchip Technology		$ 33,919	$ 64,899	$ (79,444)	$ 195,566
Basic net income (loss) from continuing operations, per common share (in USD per share)		$ 0.17	$ 0.32	$ (0.34)	$ 0.96
Basic net loss from discontinued operations, per common share (in USD per share)		(0.01)	0	(0.03)	0
Basic net income (loss) attributable to Microchip Technology, per common share (in USD per share)		0.16	0.32	(0.37)	0.96
Diluted net income (loss) from continuing operations, per common share (in USD per share)		0.15	0.30	(0.34)	0.90
Diluted net loss from discontinued operations, per common share (in USD per share)		(0.01)	0	(0.03)	0
Diluted net income (loss) attributable to Microchip Technology, per common share (in USD per share)		0.14	0.30	(0.37)	0.90
Dividends declared per common share (in USD per share)		$ 0.3600	$ 0.3580	$ 0.7195	$ 0.7155
Basic common shares outstanding		215,524	204,275	214,935	203,254
Diluted common shares outstanding		233,960	217,099	214,935	216,933
[1]	Includes share-based compensation expense as follows:Cost of sales 4,100 2,398 11,997 4,055 Research and development 10,171 8,670 27,688 15,768 Selling, general and administrative 10,119 11,958 44,284 17,315

CONDENSED CONSOLIDATED STATEME5

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (PARENTHETICAL) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Sep. 30, 2016		Sep. 30, 2015	Sep. 30, 2016		Sep. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	$ 24,390		$ 23,026	$ 83,969		$ 37,138
Cost of Sales
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	4,100	[1]	2,398	11,997	[1]	4,055	[1]
Research and Development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	10,171		8,670	27,688		15,768
Selling General And Administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	$ 10,119		$ 11,958	$ 44,284		$ 17,315
[1]	During the three and six months ended September 30, 2016, $2.7 million and $5.5 million, respectively, of share-based compensation expense was capitalized to inventory. The amount of share-based compensation included in cost of sales during the three months ended September 30, 2016 included $4.1 million of previously capitalized share-based compensation expense in inventory that was sold. The amount of share-based compensation included in cost of sales during the six months ended September 30, 2016 included $7.8 million of previously capitalized share-based compensation expense in inventory that was sold and $4.2 million of share-based compensation expense related to the Company's acquisition of Atmel that was not previously capitalized to inventory. During the three and six months ended September 30, 2015, $1.8 million and $3.6 million, respectively, of share-based compensation expense was capitalized to inventory and $2.4 million and $4.1 million, respectively, of previously capitalized share-based compensation expense in inventory was sold.

CONDENSED CONSOLIDATED STATEME6

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 33,919	$ 64,899	$ (79,444)	$ 195,359
Less: Net loss attributable to noncontrolling interests	0	0	0	207
Net income (loss) attributable to Microchip Technology	33,919	64,899	(79,444)	195,566
Unrealized holding (losses) gains, net of tax effect	(404)	2,082	(1,729)	70
Reclassification of realized transactions, net of tax effect	7	(6)	89	(13,965)
Actuarial losses related to defined benefit pension plans, net of tax benefit of $742, $0, $3,745, and $0, respectively	(1,525)	0	(8,330)	0
Change in net foreign currency translation adjustment	454	0	(2,569)	0
Other comprehensive (loss) income, net of taxes attributable to Microchip Technology	(1,468)	2,076	(12,539)	(13,895)
Comprehensive income (loss)	32,451	66,975	(91,983)	181,464
Less: Comprehensive loss attributable to noncontrolling interests	0	0	0	207
Comprehensive income (loss) attributable to Microchip Technology	$ 32,451	$ 66,975	$ (91,983)	$ 181,671

CONDENSED CONSOLIDATED STATEME7

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME (PARENTHETICAL) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
Other comprehensive (income) loss, pension and other postretirement benefit plans, tax	$ 742	$ 0	$ 3,745	$ 0

CONDENSED CONSOLIDATED STATEME8

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (unaudited) - USD ($) $ in Thousands	6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities:
Net (loss) income	$ (79,444)	$ 195,359
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation and amortization	225,957	131,484
Deferred income taxes	(17,820)	(35,999)
Share-based compensation expense related to equity incentive plans	83,969	37,138
Excess tax benefit from share-based compensation	0	(407)
Amortization of debt discount on convertible debentures	24,413	23,746
Amortization of debt issuance costs	2,118	1,920
Losses on equity method investments	112	233
Gains on sale of assets	(75)	(860)
Losses on write-down of fixed assets	317	0
Impairment of intangible assets	1,984	530
Realized losses (gains) on available-for-sale investment	89	(13,959)
Realized gains on equity method investment	(468)	(2,225)
Amortization of premium on available-for-sale investments	0	4,732
Special charges	0	511
Changes in operating assets and liabilities, excluding impact of acquisitions:
(Increase) decrease in accounts receivable	(25,432)	5,170
Decrease (increase) in inventories	215,950	(4,597)
Increase in deferred income on shipments to distributors	39,764	13,492
Decrease in accounts payable and accrued liabilities	(22,017)	(31,443)
Change in other assets and liabilities	(13,641)	6,589
Operating cash flows related to discontinued operations	10,314	0
Net cash provided by operating activities	446,090	331,414
Cash flows from investing activities:
Purchases of available-for-sale investments	(25)	(1,112,089)
Sales and maturities of available-for-sale investments	470,565	795,771
Sale of equity method investment	468	2,667
Acquisition of Atmel, net of cash acquired	(2,747,516)	0
Acquisition of Micrel, net of cash acquired	0	(343,928)
Purchase of additional controlling interest in ISSC	0	(18,051)
Investments in other assets	(3,232)	(2,981)
Proceeds from sale of assets	66	14,296
Capital expenditures	(36,646)	(63,554)
Net cash used in investing activities	(2,316,320)	(727,869)
Cash flows from financing activities:
Repayments of revolving loan under credit facility	(951,500)	(190,000)
Proceeds from borrowings on revolving loan under credit facility	1,385,000	1,024,500
Deferred financing costs	0	(406)
Payment of cash dividends	(154,877)	(145,016)
Repurchase of common stock	0	(363,829)
Proceeds from sale of common stock	25,452	13,520
Tax payments related to shares withheld for vested restricted stock units	(35,843)	(11,124)
Capital lease payments	(391)	(334)
Excess tax benefit from share-based compensation	0	407
Net cash provided by financing activities	267,841	327,718
Effect of foreign exchange rate changes on cash and cash equivalents	(374)	0
Net decrease in cash and cash equivalents	(1,602,763)	(68,737)
Cash and cash equivalents at beginning of period	2,092,751	607,815
Cash and cash equivalents at end of period	$ 489,988	$ 539,078

Basis of Presentation (Notes)

Basis of Presentation (Notes)	6 Months Ended
	Sep. 30, 2016
Basis of Presentation [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements include the accounts of Microchip Technology Incorporated and its majority-owned and controlled subsidiaries (the Company). All intercompany balances and transactions have been eliminated in consolidation. The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States of America (US GAAP), pursuant to the rules and regulations of the Securities and Exchange Commission (the SEC). The information furnished herein reflects all adjustments which are, in the opinion of management, of a normal recurring nature and necessary for a fair statement of the results for the interim periods reported. Certain information and footnote disclosures normally included in audited consolidated financial statements have been condensed or omitted pursuant to such SEC rules and regulations. It is suggested that these condensed consolidated financial statements be read in conjunction with the audited consolidated financial statements and the notes thereto included in the Company's Annual Report on Form 10-K for the fiscal year ended March 31, 2016 . The results of operations for the six months ended September 30, 2016 are not necessarily indicative of the results that may be expected for the fiscal year ending March 31, 2017 or for any other period. As further discussed in Note 3, on April 4, 2016, the Company completed its acquisition of Atmel Corporation (Atmel) and the Company's financial results include Atmel's results beginning as of such acquisition date.

Recently Issued Accounting Pron

Recently Issued Accounting Pronouncements (Notes)	6 Months Ended
	Sep. 30, 2016
Accounting Changes and Error Corrections [Abstract]
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements Recently Adopted Accounting Pronouncements During the three months ended June 30, 2016 , the Company adopted Accounting Standards Update (ASU) 2015-03- Simplifying the Presentation of Debt Issuance Costs . The new guidance was adopted on a retrospective basis and as a result, debt issuance costs historically included in other assets have been reclassified as a direct deduction from the carrying amount of the associated debt. Related prior period information included on the Company's condensed consolidated balance sheets has been retrospectively adjusted as follows (amounts in thousands). As of March 31, 2016 As Reported Adjustments As Adjusted Other assets $ 109,025 $ (29,632 ) $ 79,393 Total assets $ 5,567,515 $ (29,632 ) $ 5,537,883 Senior convertible debentures $ 1,234,733 $ (18,420 ) $ 1,216,313 Junior convertible debentures $ 196,304 $ (2,368 ) $ 193,936 Long-term line of credit $ 1,052,000 $ (8,844 ) $ 1,043,156 Total liabilities and stockholder's equity $ 5,567,515 $ (29,632 ) $ 5,537,883 During the three months ended June 30, 2016 , the Company elected to early adopt ASU 2016-09, Compensation - Stock Compensation, Improvements to Employee Share-Based Payment Accounting (Topic 718), which simplifies several aspects of the accounting for share-based payment transactions. Under this standard, entities are permitted to make an accounting policy election to either estimate forfeitures on share-based payment awards, as previously required, or to recognize forfeitures as they occur. The Company has elected to recognize forfeitures as they occur and the impact of that change in accounting policy has been recorded as a $2.0 million cumulative effect adjustment as an increase to the Company's retained earnings and a decrease to additional paid-in capital as of April 1, 2016. The Company also recorded a cumulative-effect adjustment to retained earnings for the increase of $2.3 million in long-term deferred tax assets related to the forfeiture rate reduction on outstanding share-based payment awards. Additionally, ASU 2016-09 eliminates the requirement to report excess tax benefits and certain tax deficiencies related to share-based payment transactions in additional paid-in capital. In accordance with the new standard, the Company will record excess tax benefits and tax deficiencies as income tax benefit or provision on a prospective basis in its condensed consolidated statements of operations. The standard also eliminates the requirement that excess tax benefits be realized before companies can recognize them. Accordingly, the Company has recorded a $47.2 million cumulative-effect adjustment to its retained earnings and long-term deferred tax assets as of April 1, 2016 for previously unrecognized excess tax benefits. ASU 2016-09 also requires excess tax benefits to be reported as operating activities in the statement of cash flows rather than as a financing activity. The Company has elected to apply the change in cash flow classification on a prospective basis and prior periods were not retrospectively adjusted. Recently Issued Accounting Pronouncements Not Yet Adopted 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. 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 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. 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 will have on its condensed consolidated financial statements. The Company has not yet elected a transition method. 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 condensed 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 condensed 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, with early adoption permitted. The standard is to be applied using the modified retrospective approach to all periods presented. The Company is currently evaluating the impact the adoption of this standard will have on its condensed consolidated financial statements. In October 2016, the FASB issued ASU 2016-16- Intra-Entity Transfers of Assets Other Than Inventory . This standard addresses the recognition of current and deferred income taxes resulting from an intra-entity transfer of any asset other than inventory. Prior to the adoption of ASU 2016-16, a company will defer for financial reporting purposes the income tax expense resulting from an intra-entity asset transfer, including the taxes currently payable or paid. Upon adoption of ASU 2016-16, a company will recognize current and deferred income taxes that result from such transfers in the period in which they occur. ASU 2016-16 is effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2017 and is applied on a modified retrospective basis through a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. The Company is currently evaluating the impact the adoption of this standard will have on its condensed consolidated financial statements but expects to recognize its previously deferred tax related to intra-entity transfers upon adoption of ASU 2016-16 as of April 1, 2018 with a cumulative-effect reduction to retained earnings.

Business Acquisitions (Notes)

Business Acquisitions (Notes)	6 Months Ended
	Sep. 30, 2016
Business Combinations [Abstract]
Business Acquisitions	Business Acquisitions 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, issued an aggregate of 10.1 million shares of its common stock to Atmel stockholders valued at $486.1 million based on the closing price of the Company's common stock on April 4, 2016 and incurred transaction and other fees of approximately $ 14.9 million . The total consideration transferred in the acquisition, including approximately $ 7.5 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 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 independent third-party appraisers to assist management in its valuation. The purchase price allocation has not been finalized and is based on estimates and assumptions that are subject to change related to the valuation of inventory, intangible assets, taxes and other assets and liabilities. 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 valuation 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 previously reported figures at June 30, 2016, 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). Assets acquired Previously Reported June 30, 2016 Adjustments September 30, 2016 Cash and cash equivalents $ 230,266 $ — $ 230,266 Accounts receivable 135,427 135,427 Inventories 333,208 1,955 335,163 Prepaid expenses and other current assets 28,360 — 28,360 Assets held for sale 24,394 24,394 Property, plant and equipment 129,587 — 129,587 Goodwill 1,378,317 (6,215 ) 1,372,102 Purchased intangible assets 1,880,245 (2,300 ) 1,877,945 Long-term deferred tax assets 49,466 (106 ) 49,360 Other assets 5,948 1,587 7,535 Total assets acquired 4,195,218 (5,079 ) 4,190,139 Liabilities assumed Accounts payable (55,686 ) (55,686 ) Other current liabilities (119,152 ) (317 ) (119,469 ) Long-term line of credit (192,000 ) (192,000 ) Deferred tax liabilities (74,334 ) (551 ) (74,885 ) Long-term income tax payable (174,380 ) 5,947 (168,433 ) Other long-term liabilities (106,688 ) (106,688 ) Total liabilities assumed (722,240 ) 5,079 (717,161 ) Purchase price allocated $ 3,472,978 $ — $ 3,472,978 Purchased Intangible Assets Weighted Average Useful Life April 4, 2016 (in years) (in thousands) Core/developed technology 11 $ 1,076,540 In-process technology — 140,700 Customer-related 6 630,600 Backlog 1 28,300 Other 5 1,805 Total purchased intangible assets $ 1,877,945 Purchased intangible assets include core and developed technology, in-process research and development, customer-related intangibles, acquisition-date backlog and other intangible assets. 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 in a manner based on 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 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 based on 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 have a one year useful life and are being amortized on a straight-line basis over that period. The total weighted average amortization period of intangible assets acquired as a result of the Atmel transaction is 9 years. Amortization expense associated with acquired intangible assets is not deductible for tax purposes. Thus, approximately $ 159.6 million was established as a net deferred tax liability for the future amortization of the intangible assets. The amount of continuing Atmel net sales included in the Company's condensed consolidated statements of operations for the three and six months ended September 30, 2016 was approximately $ 274.1 million and $493.1 million , respectively. The amount of Atmel's net loss from continuing operations included in the Company's condensed consolidated statements of operations was $ 95.8 million and $259.4 million for the three and six months ended September 30, 2016, respectively. The following unaudited pro-forma consolidated results of operations for the three and six months ended September 30, 2016 and 2015 assume the closing of the Atmel acquisition occurred as of April 1, 2015. The pro-forma adjustments are mainly comprised of acquired inventory fair value costs, amortization of purchased intangible assets, distributor revenue recognition adjustments and share based compensation due to accelerated vesting of outstanding equity awards. 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, 2015 or of results that may occur in the future (amounts in thousands except per share data): Three Months Ended Six Months Ended September 30, September 30, 2016 2015 2016 2015 Net sales $ 872,034 $ 827,924 $ 1,709,152 $ 1,624,716 Net income (loss) from continuing operations $ 82,332 $ (78,526 ) $ 82,102 $ (150,366 ) Basic net income (loss) per common share $ 0.38 $ (0.37 ) $ 0.38 $ (0.70 ) Diluted net income (loss) per common share $ 0.35 $ (0.37 ) $ 0.35 $ (0.70 ) Acquisition of Micrel On August 3, 2015, the Company acquired Micrel, Incorporated (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 8.6 million shares of its common stock to Micrel shareholders. The number of shares issued in the transaction was subsequently repurchased by the Company in the open market during the fiscal 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, automotive and communications. 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 condensed 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. The table below represents the allocation of the purchase price 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. The purchase price allocation was finalized as of June 30, 2016 (amounts in thousands): Assets acquired Final Cash and cash equivalents $ 99,196 Accounts receivable, net 14,096 Inventories 73,468 Prepaid expenses and other current assets 10,652 Property, plant and equipment, net 38,491 Goodwill 440,978 Purchased intangible assets 273,500 Other assets 4,268 Total assets acquired 954,649 Liabilities assumed Accounts payable (11,068 ) Other current liabilities (31,552 ) Deferred tax liabilities (88,035 ) Long-term income tax payable (7,637 ) Other long-term liabilities (127 ) Total liabilities assumed (138,419 ) Purchase price allocated $ 816,230 Purchased Intangible Assets Weighted Average Useful Life August 3, 2015 (in years) (in thousands) Core/developed technology 10 $ 175,800 In-process technology — 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.

Discontinued Operations and Ass

Discontinued Operations and Assets Held for Sale (Notes)	6 Months Ended
	Sep. 30, 2016
Discontinued Operations and Disposal Groups [Abstract]
Discontinued Operations and Assets Held for Sale	Discontinued Operations and Assets Held for Sale Discontinued operations include the mobile touch business that the Company acquired as part of its acquisition of Atmel. The mobile touch business has been marketed for sale since the acquisition of Atmel on April 4, 2016 based on management's decision that it was not a strategic fit for the Company's product portfolio. The Company announced on November 1, 2016, that it had entered into an agreement to sell the foregoing mobile touch business assets. See Note 26, Subsequent Event, for further information. For financial statement purposes, the results of operations for this discontinued business have been segregated from those of the continuing operations and are presented in the Company's condensed consolidated financial statements as discontinued operations and the net assets of the remaining discontinued business have been presented as assets held for sale. The results of discontinued operations for the three and six months ended September 30, 2016 are as follows (amounts in thousands): September 30, 2016 Three Months Ended Six Months Ended Net sales $ 8,035 $ 17,411 Cost of sales 6,939 15,363 Operating expenses 2,946 9,371 Income tax benefit (195 ) (1,530 ) Net loss from discontinued operations $ (1,655 ) $ (5,793 ) As of September 30, 2016 , assets held for sale are comprised of the following (amounts in thousands): Assets Held for Sale Inventories $ 6,580 Intangible assets 7,500 Total assets held for sale $ 14,080

Special Charges (Notes)

Special Charges (Notes)	6 Months Ended
	Sep. 30, 2016
Other Nonrecurring (Income) Expense [Abstract]
Special charges	Special Charges The Company incurred special charges related to severance, office closing and other costs associated with its acquisition activity of $9.5 million and $ 31.6 million for the three and six months ended September 30, 2016 , respectively (of which $ 25.6 million was paid during the six months ended September 30, 2016) compared to $6.6 million and $ 8.2 million for the three and six months ended September 30, 2015 , respectively.

Segment Information (Notes)

Segment Information (Notes)	6 Months Ended
	Sep. 30, 2016
Segment Reporting [Abstract]
Segment Information	Segment Information The Company's reportable segments are 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 net sales and gross profit for each segment for the three and six months ended September 30, 2016 (amounts in thousands): Three Months Ended Six Months Ended September 30, 2016 September 30, 2016 Net Sales Gross Profit Net Sales Gross Profit Semiconductor products $ 847,694 $ 386,951 $ 1,626,517 $ 714,853 Technology licensing 23,670 23,670 44,258 44,258 Total $ 871,364 $ 410,621 $ 1,670,775 $ 759,111 The following table represents net sales and gross profit for each segment for the three and six months ended September 30, 2015 (amounts in thousands): Three Months Ended Six Months Ended September 30, 2015 September 30, 2015 Net Sales Gross Profit Net Sales Gross Profit Semiconductor products $ 518,216 $ 277,775 $ 1,028,905 $ 563,529 Technology licensing 23,175 23,175 46,438 46,438 Total $ 541,391 $ 300,950 $ 1,075,343 $ 609,967

Investments (Notes)

Investments (Notes)	6 Months Ended
	Sep. 30, 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 September 30, 2016 (amounts in thousands): Available-for-sale Securities Adjusted Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Marketable equity securities $ 2,140 $ — $ (1,292 ) $ 848 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 $ 471,485 $ 447 $ (99 ) $ 471,833 At September 30, 2016 , the Company's available-for-sale securities are $ 0.8 million presented on the condensed consolidated balance sheets as short-term investments. At March 31, 2016 , the Company's available-for-sale securities are presented on the condensed consolidated balance sheets as short-term investments of $353.3 million and long-term investments of $118.5 million . The Company sold available-for-sale investments for proceeds of $ 470.6 million during the six months ended September 30, 2016 . An immaterial amount of available-for-sale investments were sold during the three months ended September 30, 2016 . The Company sold available-for-sale investments during the first quarter of fiscal 2017 and 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 sold available-for-sale investments for proceeds of $ 46.7 million and $ 135.8 million during the three and six months ended September 30, 2015 , respectively. The Company had no material realized gains from the sale of available-for-sale securities during the three and six months ended September 30, 2016 . During the three months ended September 30, 2015 , the Company had no material realized gains from sales of available-for-sale marketable equity and debt securities and for the six months ended September 30, 2015 , the Company had net realized gains of $ 14.0 million from sales of available-for-sale marketable equity and debt securities. 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 operations. 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 the length of time that the individual securities have been in a continuous unrealized loss position (amounts in thousands): September 30, 2016 Less than 12 Months 12 Months or Greater Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss Marketable equity securities $ 848 $ (1,292 ) $ — $ — $ 848 $ (1,292 ) 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 — $ 148,562 $ (99 ) $ 1,000 $ — $ 149,562 $ (99 ) Management does not believe any of the unrealized losses represent an other-than-temporary impairment based on its evaluation of available evidence as of September 30, 2016 and the Company's intent is to hold these investments until these assets are no longer impaired.

Fair Value Measurements (Notes)

Fair Value Measurements (Notes)	6 Months Ended
	Sep. 30, 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. Assets Measured at Fair Value on a Recurring Basis Assets measured at fair value on a recurring basis at September 30, 2016 are as follows (amounts in thousands): Quoted Prices in Active Markets for Identical Instruments (Level 1) Significant Other Observable Inputs (Level 2) Total Balance Assets Cash and cash equivalents: Money market mutual funds $ 41,494 $ — $ 41,494 Deposit accounts — 448,494 448,494 Short-term investments: Marketable equity securities 848 — 848 Total assets measured at fair value $ 42,342 $ 448,494 $ 490,836 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) 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 There were no transfers between Level 1 and Level 2 during the three and six -months ended September 30, 2016 or the fiscal year ended March 31, 2016 . Assets and Liabilities Measured and Recorded at Fair Value on a Non-Recurring Basis The Company's non-marketable equity, cost method investments, certain acquired liabilities 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 each of the three and six -month periods ended September 30, 2016 and September 30, 2015 . These investments are included in other assets on the condensed consolidated balance sheet. 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)	6 Months Ended
	Sep. 30, 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 September 30, 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 excluding debt issuance costs. 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 September 30, 2016 approximated the carrying value and are considered Level 2 in the fair value hierarchy described in Note 8. 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. The following table shows the carrying amounts and fair values of the Company’s senior and junior subordinated convertible debentures as of September 30, 2016 and March 31, 2016 (amounts in thousands). As of September 30, 2016 , the carrying amounts of the Company's senior and junior subordinated convertible debentures have been reduced by debt issuance costs of $ 17.5 million and $ 2.3 million , respectively. As of March 31, 2016 , the carrying amounts of the Company's senior and junior subordinated convertible debentures have been reduced by debt issuance costs of $ 18.4 million and $ 2.4 million , respectively. September 30, 2016 March 31, 2016 Carrying Amount Fair Value Carrying Amount Fair Value 1.625% Senior Subordinated Convertible Debentures $ 1,238,731 $ 2,216,539 $ 1,216,313 $ 1,762,088 2.125% Junior Subordinated Convertible Debentures $ 196,868 $ 1,484,805 $ 193,936 $ 1,143,117

Accounts Receivable (Notes)

Accounts Receivable (Notes)	6 Months Ended
	Sep. 30, 2016
Accounts Receivable, Net [Abstract]
Accounts Receivable	Accounts Receivable Accounts receivable consists of the following (amounts in thousands): September 30, 2016 March 31, 2016 Trade accounts receivable $ 449,495 $ 289,013 Other 3,931 3,710 Total accounts receivable, gross 453,426 292,723 Less allowance for doubtful accounts 2,384 2,540 Total accounts receivable, net $ 451,042 $ 290,183

Inventories (Notes)

Inventories (Notes)	6 Months Ended
	Sep. 30, 2016
Inventory Disclosure [Abstract]
Inventories	Inventories The components of inventories consist of the following (amounts in thousands): September 30, 2016 March 31, 2016 Raw materials $ 15,227 $ 12,179 Work in process 292,536 208,283 Finished goods 116,927 86,353 Total inventories $ 424,690 $ 306,815 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.

Property, Plant and Equipment (

Property, Plant and Equipment (Notes)	6 Months Ended
	Sep. 30, 2016
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Property, Plant and Equipment Property, plant and equipment consists of the following (amounts in thousands): September 30, 2016 March 31, 2016 Land $ 73,692 $ 63,907 Building and building improvements 500,462 458,379 Machinery and equipment 1,750,646 1,645,617 Projects in process 107,801 99,370 Total property, plant and equipment, gross 2,432,601 2,267,273 Less accumulated depreciation and amortization 1,715,603 1,657,877 Total property, plant and equipment, net $ 716,998 $ 609,396 Depreciation expense attributed to property, plant and equipment was $ 30.0 million and $61.0 million for the three and six months ended September 30, 2016 , respectively. Depreciation expense attributed to property, plant and equipment was $ 26.2 million and $ 50.9 million for the three and six months ended September 30, 2015 , respectively.

Intangible Assets and Goodwill

Intangible Assets and Goodwill (Notes)	6 Months Ended
	Sep. 30, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets and Goodwill	Intangible Assets and Goodwill Intangible assets consist of the following (amounts in thousands): September 30, 2016 Gross Amount Accumulated Amortization Net Amount Core and developed technology $ 1,813,689 $ (347,137 ) $ 1,466,552 Customer-related 909,141 (258,151 ) 650,990 Trademarks and trade names 11,700 (8,604 ) 3,096 Backlog 28,300 (14,150 ) 14,150 In-process technology 186,067 — 186,067 Distribution rights 5,580 (5,324 ) 256 Other 1,805 (210 ) 1,595 Total $ 2,956,282 $ (633,576 ) $ 2,322,706 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 The Company amortizes intangible assets over their expected useful lives, which range between 1 and 15 years. During the three months ended June 30, 2016, as a result of the Atmel transaction, the Company acquired $ 1,076.5 million of core and developed technology which has a weighted average amortization period of 11 years, $ 630.6 million of customer-related intangible assets which have a weighted average amortization period of 6 years, $ 28.3 million of intangible assets related to backlog with an amortization period of 1 year, $ 1.8 million of other intangible assets which have a weighted average amortization period of 5 years and $ 140.7 million of in-process technology which will begin amortization once the technology reaches technological feasibility. During the six months ended September 30, 2016 , $ 8.9 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 the remainder of fiscal 2017 through fiscal 2021, absent any future acquisitions or impairment charges (amounts in thousands): Year ending March 31, Projected Amortization Expense 2017 $170,507 2018 492,584 2019 364,138 2020 314,558 2021 257,223 Amortization expense attributed to intangible assets was $ 82.8 million and $165.3 million for the three and six months ended September 30, 2016 , respectively. Amortization expense attributed to intangible assets was $ 44.9 million and $80.6 million for the three and six months ended September 30, 2015 , respectively. In the three and six months ended September 30, 2016 , approximately $ 1.0 million and $1.9 million was charged to cost of sales, respectively, and approximately $ 81.8 million and $ 163.4 million was charged to operating expenses, respectively. In the three and six months ended September 30, 2015 , approximately $ 0.9 million and $ 1.7 million was charged to cost of sales, respectively, and approximately $ 44.0 million and $ 78.9 million was charged to operating expenses, respectively. The Company recognized no impairment charges for the three months ended September 30, 2016 and $ 2.0 million for the six months ended September 30, 2016 . The Company recognized impairment charges of $0.5 million in each of the three and six months ended September 30, 2015 . Goodwill activity for the six months ended September 30, 2016 was as follows (amounts in thousands): Semiconductor Products Reporting Unit Technology Licensing Reporting Unit Balance at March 31, 2016 $ 993,452 $ 19,200 Additions due to the acquisition of Atmel 1,372,102 — Adjustments due to the acquisition of Micrel (14 ) — Balance at September 30, 2016 $ 2,365,540 $ 19,200 At March 31, 2016 , the Company applied a qualitative goodwill impairment test to its two reporting units, concluding it was not more likely than not that goodwill was impaired. Through September 30, 2016 , the Company has never recorded an impairment charge against its goodwill balance.

Income Taxes (Notes)

Income Taxes (Notes)	6 Months Ended
	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The provision for income taxes reflects tax on foreign earnings and federal and state tax on U.S. earnings. The Company had a negative effective tax rate of 12.4% for the six months ended September 30, 2016 and a negative effective tax rate of 12.6% for the six months ended September 30, 2015 . The Company's effective tax rate for the six months ended September 30, 2016 is lower compared to the prior year primarily due to acquisition related expenses. The Company's effective tax rate is lower than statutory rates in the U.S. due primarily to its mix of earnings in foreign jurisdictions with lower tax rates as well as numerous tax holidays it receives related to its Thailand manufacturing operations 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 effected tax rate. The remaining material components of foreign income taxed at a rate lower than the U.S. are earnings accrued in Ireland and earnings accrued by the Company's offshore technology company which is resident in the Cayman Islands. The following tables summarize the activity related to the Company's gross unrecognized tax benefits for the six months ended September 30, 2016 and the year ended March 31, 2016 (amounts in thousands): Six Months Ended September 30, 2016 Balance at March 31, 2016 $ 220,669 Increases related to acquisitions 194,018 Decreases related to settlements with tax authorities (7,654 ) Decreases related to statute of limitation expirations (1,338 ) Increases related to current year tax positions 15,796 Decreases related to prior year tax positions (134 ) Balance at September 30, 2016 $ 421,357 Year Ended March 31, 2016 Balance at March 31, 2015 $ 170,654 Increases related to acquisitions 46,245 Decreases related to settlements with tax authorities (7,954 ) Decreases related to statute of limitation expirations (4,591 ) Increases related to current year tax positions 16,315 Balance at March 31, 2016 $ 220,669 As of September 30, 2016 and March 31, 2016, the Company had accrued approximately $ 15.9 million and $2.4 million , respectively, related to the potential payment of interest on the Company's uncertain tax positions with the increase being primarily composed of a $ 9.3 million increase related to acquisitions. As of September 30, 2016 and March 31, 2016, the Company had accrued for approximately $ 60.7 million and $27.6 million respectively, in penalties related to its uncertain tax positions with the increase being primarily composed of a $ 25.6 million increase related to acquisitions. The Company's practice is to recognize interest and/or penalties related to income tax matters in income tax expense. 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 2005 and later tax years remain effectively open for examination by tax authorities. The U.S. Internal Revenue Service (IRS) is currently auditing the Company'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 2007. 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 laws 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 would 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 it is reasonably possible that the unrecognized tax benefits would materially change in the next 12 months.

1.625% Senior Subordinated Conv

1.625% Senior Subordinated Convertible Debentures (Notes)	6 Months Ended
	Sep. 30, 2016
Senior Subordinated Convertible Debenture Due 2025
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 15.3437 shares of common stock per $ 1,000 of principal amount of debentures, representing a base conversion price of approximately $ 65.17 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 7.6718 shares of common stock per $ 1,000 principal amount of debentures. However, in no event will the conversion rate exceed 20.3915 (adjusted to 21.4811 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 debt component of the debt issuance costs is recorded as a direct deduction from the carrying value of the debentures 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 September 30, 2016 and March 31, 2016 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 debt discount is being amortized to interest expense at the effective interest rate of 5.9% over the contractual term of the note. The unamortized debt discount was $ 468.7 million at September 30, 2016 and $ 490.3 million at March 31, 2016 . The remaining period over which the unamortized debt discount will be recognized as non-cash interest expense is 8.38 years. In the three and six months ended September 30, 2016 , the Company recognized $ 10.8 million and $ 21.5 million , respectively, in non-cash interest expense related to the amortization of the debt discount, compared to $10.6 million and $21.1 million in the three and six months ended September 30, 2015 , respectively. The Company recognized $7.0 million and $14.0 million of interest expense related to the 1.625% coupon on the debentures in each of the three and six month periods ended September 30, 2016 , and 2015, respectively.

2.125% Junior subordinated conv

2.125% Junior subordinated convertible debentures (Notes)	6 Months Ended
	Sep. 30, 2016
Junior Subordinated Convertible Debentures Due 2037
Debt Instrument [Line Items]
Junior subordinated convertible debentures	2.125% Junior Subordinated Convertible Debentures 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 September 30, 2016 , the holders of the debentures had the right to convert their debentures between October 1, 2016 and December 31, 2016 because for at least 20 trading days during the 30 consecutive trading day period ending on September 30, 2016 , the Company's common stock had a last reported sale price greater than 130% of the conversion price. As of September 30, 2016 , the Company has classified the junior subordinated convertible debentures as long-term on its consolidated balance sheets as the Company has the intent and ability to refinance the obligation on a long-term basis. As of September 30, 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 41.6895 shares of common stock per $ 1,000 of principal amount of debentures, representing a conversion price of approximately $ 23.99 per share of common stock. The if-converted value of the debentures exceeded the principal amount by $ 914.6 million at September 30, 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 September 30, 2016 and at March 31, 2016 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 debt discount is being amortized to interest expense at the effective interest rate of 9.1% over the contractual term of the note. The unamortized debt discount was $ 375.4 million at September 30, 2016 and $ 378.3 million at March 31, 2016 . The remaining period over which the unamortized debt discount will be recognized as non-cash interest expense is 21.21 years. In the three and six months ended September 30, 2016 , the Company recognized $1.5 million and $2.9 million , respectively, in non-cash interest expense related to the amortization of the debt discount compared to $1.3 million and $2.6 million for the three and six months ended September 30, 2015 , respectively. The Company recognized $3.1 million and $6.2 million of interest expense related to the 2.125% coupon on the debentures in the three and six month periods ended September 30, 2016 , compared to $3.1 million and $6.1 million for the three and six month periods ended September 30, 2015 , respectively.

Credit facility (Notes)

Credit facility (Notes)	6 Months Ended
	Sep. 30, 2016
Line of 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 September 30, 2016 , $ 1.678 billion of revolving credit facility borrowings were outstanding under the credit agreement compared to $ 1.052 billion at March 31, 2016 . The carrying values reflected in the Company's condensed consolidated balance sheets as of September 30, 2016 and March 31, 2016 have been reduced by debt issuance costs of $ 7.7 million and $ 8.8 million , respectively. 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 September 30, 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 (as defined in that agreement) 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 Company elected to use this feature in conjunction with its acquisition of Atmel during the quarter ended June 30, 2016. 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 $ 12.0 million and $23.6 million in the three and six months ended September 30, 2016 , respectively, and $ 4.9 million and $8.5 million for the three and six months ended September 30, 2015 , respectively. 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 borrowings outstanding at September 30, 2016 related to the credit agreement was 2.55% . 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 September 30, 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.

Pension Plans (Notes)

Pension Plans (Notes)	6 Months Ended
	Sep. 30, 2016
Compensation and Retirement Disclosure [Abstract]
Pension and Other Postretirement Benefits Disclosure	Pension Plans In connection with its acquisition of Atmel, the Company assumed unfunded defined benefit pension plans that cover certain French and German employees. Plan benefits are provided in accordance with local statutory requirements. Benefits are based on years of service and employee compensation levels. Pension liabilities and charges are based upon various assumptions, updated annually, including discount rates, future salary increases, employee turnover, and mortality rates. The Company’s French pension plan provides for termination benefits paid to covered French employees only at retirement, and consists of approximately one to five months of salary. The Company's German pension plan provides for defined benefit payouts for covered German employees following retirement. The aggregate net pension expense relating to these two plans are as follows (amounts in thousands): September 30, 2016 Three Months Ended Six Months Ended Service costs $ 363 $ 727 Interest costs 241 484 Amortization of actuarial loss 64 129 Settlements — 231 Net pension period cost $ 668 $ 1,571 The change in projected benefit obligation and the accumulated benefit obligation, were as follows (amounts in thousands): Projected benefit obligation at April 4, 2016 $ 40,313 Service cost 727 Interest cost 484 Settlements 231 Actuarial losses (gains) 12,060 Benefits paid (216 ) Foreign currency exchange rate changes (55 ) Projected benefit obligation at September 30, 2016 $ 53,544 Accumulated benefit obligation at September 30, 2016 48,130 As the defined benefit plans are unfunded, the liability recognized on the condensed consolidated balance sheets as of September 30, 2016 was $53.5 million of which $ 0.6 million is included in accrued liabilities and $ 52.9 million is included in other long-term liabilities. Actuarial assumptions used to determine benefit obligations for the plans were as follows at September 30, 2016 : Assumed discount rate 0.77% - 1.14% Assumed compensation rate of increase 3.00% The discount rate is based on the quarterly average yield for Euros treasuries with a duration of 30 years, plus a supplement for corporate bonds (Euros, AA rating). Future estimated expected benefit payments for the remainder of fiscal 2017 through 2026 are as follows (amounts in thousands): Fiscal Year Ending March 31, Expected Benefit Payments 2017 $ 483 2018 792 2019 985 2020 913 2021 1,198 2022 through 2026 9,185 Total $ 13,556 The Company's pension liability represents the present value of estimated future benefits to be paid. Actuarial losses (gains) for the three and six months ended September 30, 2016 is comprised of a $2.3 million loss and a $12.8 million loss, respectively, recognized due to declines in the discount rates used to calculate the present value of pension obligation and a $ 0.7 million settlement gain for the six months ended September 30, 2016 . Net actuarial losses (gains) will be recognized as a component of net periodic pension cost during fiscal 2018, which is included in accumulated other comprehensive loss in the condensed consolidated balance sheets as of September 30, 2016 . The Company's net periodic pension cost for fiscal 2017 is expected to be approximately $ 2.9 million . Cash funding for benefits paid was $0.1 million and $ 0.2 million for the three and six months ended September 30, 2016 , respectively. The Company expects total contributions to these plans to be approximately $ 0.5 million in fiscal 2017.

Contingencies (Notes)

Contingencies (Notes)	6 Months Ended
	Sep. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Contingencies	Contingencies In the ordinary course of the Company's business, it is exposed to various liabilities as a result of contracts, product liability, customer claims and other matters. Additionally, 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, or from customers requesting reimbursement for various costs. With respect to pending legal actions to which the Company is a party and other claims, although the outcomes are generally not determinable, the Company believes that the ultimate resolution of these matters will not have a material adverse effect on its financial position, cash flows or results of operations. Litigation and disputes relating to the semiconductor industry are not uncommon, and the Company is, from time to time, subject to such litigation and disputes. As a result, no assurances can be given with respect to the extent or outcome of any such litigation or disputes in the future. The Company accrues for claims and contingencies when losses become probable and reasonably estimable. As of the end of each applicable reporting period, the Company reviews each of its matters and, where it is probable that a liability has been or will be incurred, the Company accrues for all probable and reasonably estimable losses. Where the Company can reasonably estimate a range of losses it may incur regarding such a matter, the Company records an accrual for the amount within the range that constitutes its best estimate. If the Company can reasonably estimate a range but no amount within the range appears to be a better estimate than any other, the Company uses the amount that is the low end of such range. As of September 30, 2016 , the Company's estimate of the aggregate potential liability that is possible but not probable is approximately $ 100 million in excess of amounts accrued. 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 $ 147 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 September 30, 2016 .

Derivative Instruments (Notes)

Derivative Instruments (Notes)	6 Months Ended
	Sep. 30, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	Derivative Instruments Foreign Currency Exchange Rate Risk The Company has international operations and is thus subject to foreign currency rate fluctuations. Approximately 98% of the Company's sales are U.S. dollar denominated. However, a significant amount of the Company's expenses and liabilities are denominated in foreign currencies and 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. Net losses due to foreign exchange rate fluctuations after the effects of hedging activity were $2.9 million and $2.2 million during the three and six month periods ended September 30, 2016, respectively, compared to net losses of $1.6 million and $1.2 million during the three and six-month periods ended September 30, 2015, respectively. As of September 30, 2016 and March 31, 2016 , 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 each of the three and six months ended September 30, 2016 and 2015 . 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) on the condensed consolidated statements of operations. The Company does not apply hedge accounting to its foreign currency derivative instruments.

Comprehensive Income (Loss) (No

Comprehensive Income (Loss) (Notes)	6 Months Ended
	Sep. 30, 2016
Equity [Abstract]
Comprehensive Income	Comprehensive Income (Loss) The following table presents the changes in the components of accumulated other comprehensive income (loss) (AOCI), net of tax, for the six months ended September 30, 2016 (amounts in thousands): Unrealized holding gains (losses) available-for-sale securities Defined benefit pension plans Foreign Currency Total Accumulated other comprehensive income (loss) at March 31, 2016 $ 348 $ 44 $ (3,749 ) $ (3,357 ) Other comprehensive loss before reclassifications (1,729 ) (8,330 ) (2,569 ) (12,628 ) Amounts reclassified from accumulated other comprehensive loss 89 — — 89 Net other comprehensive loss (1,640 ) (8,330 ) (2,569 ) (12,539 ) Accumulated other comprehensive loss at September 30, 2016 $ (1,292 ) $ (8,286 ) $ (6,318 ) $ (15,896 ) The table below details where reclassifications of realized transactions out of AOCI are recorded on the condensed consolidated statements of operations (amounts in thousands): Three Months Ended Six Months Ended September 30, September 30, Description of AOCI Component 2016 2015 2016 2015 Related Statement of Income Line Unrealized (losses) gains on available-for-sale securities $ (7 ) $ 6 $ (89 ) $ 13,965 Other income

Share-Based Compensation (Notes

Share-Based Compensation (Notes)	6 Months Ended
	Sep. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation	Share-Based Compensation The following table presents the details of the Company's share-based compensation expense (amounts in thousands): Three Months Ended Six Months Ended September 30, September 30, 2016 2015 2016 2015 Cost of sales $ 4,100 (1) $ 2,398 (1) $ 11,997 (1) $ 4,055 (1) Research and development 10,171 8,670 27,688 15,768 Selling, general and administrative 10,119 11,958 44,284 17,315 Pre-tax effect of share-based compensation 24,390 23,026 83,969 37,138 Income tax benefit 8,358 8,574 29,246 12,106 Net income effect of share-based compensation $ 16,032 $ 14,452 $ 54,723 $ 25,032 (1) During the three and six months ended September 30, 2016 , $2.7 million and $5.5 million , respectively, of share-based compensation expense was capitalized to inventory. The amount of share-based compensation included in cost of sales during the three months ended September 30, 2016 included $4.1 million of previously capitalized share-based compensation expense in inventory that was sold. The amount of share-based compensation included in cost of sales during the six months ended September 30, 2016 included $7.8 million of previously capitalized share-based compensation expense in inventory that was sold and $4.2 million of share-based compensation expense related to the Company's acquisition of Atmel that was not previously capitalized to inventory. During the three and six months ended September 30, 2015 , $1.8 million and $3.6 million , respectively, of share-based compensation expense was capitalized to inventory and $2.4 million and $4.1 million , respectively, of previously capitalized share-based compensation expense in inventory was sold. Atmel Acquisition-related Equity Awards In connection with its acquisition of Atmel, the Company assumed certain restricted stock units (RSUs) granted by Atmel. The assumed awards were measured at the acquisition date based on the estimated fair value, which was a total of $ 95.9 million . A portion of that fair value, $ 7.5 million , which represented the pre-acquisition vested service provided by employees to Atmel, was included in the total consideration transferred as part of the acquisition. As of the acquisition date, the remaining portion of the fair value of those awards was $ 88.4 million , representing post-acquisition share-based compensation expense that will be recognized as these employees provide service over the remaining vesting periods. During the three months ended September 30, 2016, the Company recognized $ 6.2 million of share-based compensation expense in connection with the acquisition of Atmel. During the six months ended September 30, 2016, the Company recognized $ 49.4 million of share-based compensation expense in connection with the acquisition of Atmel, of which $ 37.2 million was due to the accelerated vesting of outstanding equity awards upon termination of certain Atmel employees.

Net Income (Loss) Per Common Sh

Net Income (Loss) Per Common Share From Continuing Operations Attributable to Microchip Technology Stockholders (Notes)	6 Months Ended
	Sep. 30, 2016
Earnings Per Share [Abstract]
Net Income (Loss) Per Common Share From Continuing Operations Attributable to Microchip Technology Stockholders	Net Income (Loss) Per Common Share From Continuing Operations Attributable to Microchip Technology Stockholders The following table sets forth the computation of basic and diluted net income (loss) per common share from continuing operations attributable to Microchip Technology stockholders (in thousands, except per share amounts): Three Months Ended Six Months Ended September 30, September 30, 2016 2015 2016 2015 Net income (loss) from continuing operations attributable to Microchip Technology $ 35,574 $ 64,899 $ (73,651 ) $ 195,566 Weighted average common shares outstanding 215,524 204,275 214,935 203,254 Dilutive effect of stock options and RSUs 4,465 3,065 — 3,228 Dilutive effect of 2037 junior subordinated convertible debentures 13,971 9,759 — 10,451 Weighted average common and potential common shares outstanding 233,960 217,099 214,935 216,933 Basic net income (loss) per common share from continuing operations attributable to Microchip Technology stockholders $ 0.17 $ 0.32 $ (0.34 ) $ 0.96 Diluted net income (loss) per common share from continuing operations attributable to Microchip Technology stockholders $ 0.15 $ 0.30 $ (0.34 ) $ 0.90 The Company computed basic net income (loss) per common share from continuing operations attributable to its stockholders using net income (loss) from continuing operations available to common stockholders and the weighted average number of common shares outstanding during the period. The Company computed diluted net income (loss) per common share from continuing operations attributable to its stockholders using net income (loss) from continuing operations available to common 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. For the six months ended September 30, 2016 , the calculation of diluted net loss per common share excluded 4,312,066 common shares from employee equity incentive plans as the related impact would have been anti-dilutive as the Company generated a net loss. Weighted average common shares exclude the effect of option shares which are not dilutive. There were no anti-dilutive option shares for the three months ended September 30, 2016 . For the three and six months ended September 30, 2015, the number of option shares that were antidilutive was 182,848 and 47,296 , respectively. Diluted net income per common share attributable to stockholders for the three months ended September 30, 2016 , includes 13,971,278 shares issuable upon the exchange of the Company's 2.125% junior subordinated convertible debentures due December 15, 2037 (see Note 16). For the six months ended September 30, 2016 , the calculations of diluted net loss per common share excluded 13,068,545 shares issuable upon the exchange of the Company's 2.125% junior subordinated convertible debentures as the related impact would have been anti-dilutive as the Company generated a loss. Diluted net income per common share from continuing operations attributable to stockholders for the three and six months ended September 30, 2015 includes 9,759,393 shares and 10,451,083 shares, respectively, issuable upon the exchange of the Company's 2.125% junior subordinated convertible debentures. 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 the three and six -month periods ended September 30, 2016 was $24.07 and $24.15 , respectively. The weighted average conversion price per share used in calculating the dilutive effect of the convertible debt for the three and six months ended September 30, 2015 was $24.87 and $24.94 , 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 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 the three and six -month periods ended September 30, 2016 was $65.38 and $65.60 , respectively. The weighted average conversion price per share used in calculating the dilutive effect of the convertible debt for the three and six -month periods ended September 30, 2015 was $67.55 and $67.75 , respectively.

Stock Repurchase (Notes)

Stock Repurchase (Notes)	6 Months Ended
	Sep. 30, 2016
Equity [Abstract]
Stock Repurchase	Stock Repurchase 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 purchased 8.6 million shares of its common stock for a total of $ 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 were no repurchases of common stock during the three and six months ended September 30, 2016 . There is no expiration date associated with this repurchase program. As of September 30, 2016 , approximately 21.5 million shares remained as treasury shares with the balance of the shares being used to fund share issuance requirements under the Company's equity incentive plans.

Dividends (Notes)

Dividends (Notes)	6 Months Ended
	Sep. 30, 2016
Dividends [Abstract]
Dividends	Dividends A quarterly cash dividend of $ 0.3600 per share was paid on September 6, 2016 in the aggregate amount of $ 77.7 million . Through the first six months of fiscal 2017, cash dividends of $0.7195 per share have been paid in the aggregate amount of $154.9 million . A quarterly cash dividend of $ 0.3605 per share was declared on November 7, 2016 and will be paid on December 5, 2016 to stockholders of record as of November 21, 2016 . The Company expects the December payment of its quarterly cash dividend to be approximately $ 80.0 million .

Subsequent Event (Notes)

Subsequent Event (Notes)	6 Months Ended
	Sep. 30, 2016
Subsequent Events [Abstract]
Subsequent Event	Subsequent Event The Company announced on November 1, 2016, that it had entered into an agreement to sell certain mobile touch business assets to Solomon Systech (International) Limited ("Solomon Systech"), a Hong Kong based semiconductor company. The transaction included the sale of certain semiconductor products, equipment and patents; and a license to certain other intellectual property and patents related to the Company's mobile touch product line. The Company also agreed to provide certain transition services to Solomon Systech. This transaction is expected to close in mid November 2016 upon the satisfaction of certain customary closing conditions. The business which is being sold to Solomon Systech was reflected as discontinued operations and assets held for sale on the Company's condensed financial statements for the three and six months ended September 30, 2016.

Recently Issued Accounting Pr35

Recently Issued Accounting Pronouncements (Tables)	6 Months Ended
	Sep. 30, 2016
Accounting Changes and Error Corrections [Abstract]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block]	Related prior period information included on the Company's condensed consolidated balance sheets has been retrospectively adjusted as follows (amounts in thousands). As of March 31, 2016 As Reported Adjustments As Adjusted Other assets $ 109,025 $ (29,632 ) $ 79,393 Total assets $ 5,567,515 $ (29,632 ) $ 5,537,883 Senior convertible debentures $ 1,234,733 $ (18,420 ) $ 1,216,313 Junior convertible debentures $ 196,304 $ (2,368 ) $ 193,936 Long-term line of credit $ 1,052,000 $ (8,844 ) $ 1,043,156 Total liabilities and stockholder's equity $ 5,567,515 $ (29,632 ) $ 5,537,883

Business Acquisitions (Tables)

Business Acquisitions (Tables)	6 Months Ended
	Sep. 30, 2016
Atmel Corporation
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 previously reported figures at June 30, 2016, 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). Assets acquired Previously Reported June 30, 2016 Adjustments September 30, 2016 Cash and cash equivalents $ 230,266 $ — $ 230,266 Accounts receivable 135,427 135,427 Inventories 333,208 1,955 335,163 Prepaid expenses and other current assets 28,360 — 28,360 Assets held for sale 24,394 24,394 Property, plant and equipment 129,587 — 129,587 Goodwill 1,378,317 (6,215 ) 1,372,102 Purchased intangible assets 1,880,245 (2,300 ) 1,877,945 Long-term deferred tax assets 49,466 (106 ) 49,360 Other assets 5,948 1,587 7,535 Total assets acquired 4,195,218 (5,079 ) 4,190,139 Liabilities assumed Accounts payable (55,686 ) (55,686 ) Other current liabilities (119,152 ) (317 ) (119,469 ) Long-term line of credit (192,000 ) (192,000 ) Deferred tax liabilities (74,334 ) (551 ) (74,885 ) Long-term income tax payable (174,380 ) 5,947 (168,433 ) Other long-term liabilities (106,688 ) (106,688 ) Total liabilities assumed (722,240 ) 5,079 (717,161 ) Purchase price allocated $ 3,472,978 $ — $ 3,472,978
Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination	Purchased Intangible Assets Weighted Average Useful Life April 4, 2016 (in years) (in thousands) Core/developed technology 11 $ 1,076,540 In-process technology — 140,700 Customer-related 6 630,600 Backlog 1 28,300 Other 5 1,805 Total purchased intangible assets $ 1,877,945
Business Acquisition, Pro Forma Information	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, 2015 or of results that may occur in the future (amounts in thousands except per share data): Three Months Ended Six Months Ended September 30, September 30, 2016 2015 2016 2015 Net sales $ 872,034 $ 827,924 $ 1,709,152 $ 1,624,716 Net income (loss) from continuing operations $ 82,332 $ (78,526 ) $ 82,102 $ (150,366 ) Basic net income (loss) per common share $ 0.38 $ (0.37 ) $ 0.38 $ (0.70 ) Diluted net income (loss) per common share $ 0.35 $ (0.37 ) $ 0.35 $ (0.70 )
Micrel Incorporated
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 August 3, 2015, 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, 2016 (amounts in thousands): Assets acquired Final Cash and cash equivalents $ 99,196 Accounts receivable, net 14,096 Inventories 73,468 Prepaid expenses and other current assets 10,652 Property, plant and equipment, net 38,491 Goodwill 440,978 Purchased intangible assets 273,500 Other assets 4,268 Total assets acquired 954,649 Liabilities assumed Accounts payable (11,068 ) Other current liabilities (31,552 ) Deferred tax liabilities (88,035 ) Long-term income tax payable (7,637 ) Other long-term liabilities (127 ) Total liabilities assumed (138,419 ) Purchase price allocated $ 816,230
Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination	Purchased Intangible Assets Weighted Average Useful Life August 3, 2015 (in years) (in thousands) Core/developed technology 10 $ 175,800 In-process technology — 21,000 Customer-related 5 71,100 Backlog 1 5,600 Total purchased intangible assets $ 273,500

Discontinued Operations and A37

Discontinued Operations and Assets Held for Sale (Tables)	6 Months Ended
	Sep. 30, 2016
Discontinued Operations and Disposal Groups [Abstract]
Disposal Groups, Including Discontinued Operations	The results of discontinued operations for the three and six months ended September 30, 2016 are as follows (amounts in thousands): September 30, 2016 Three Months Ended Six Months Ended Net sales $ 8,035 $ 17,411 Cost of sales 6,939 15,363 Operating expenses 2,946 9,371 Income tax benefit (195 ) (1,530 ) Net loss from discontinued operations $ (1,655 ) $ (5,793 ) As of September 30, 2016 , assets held for sale are comprised of the following (amounts in thousands): Assets Held for Sale Inventories $ 6,580 Intangible assets 7,500 Total assets held for sale $ 14,080

Segment Information (Tables)

Segment Information (Tables)	6 Months Ended
	Sep. 30, 2016
Segment Reporting [Abstract]
Net sales and gross profit for each segment	The following table represents net sales and gross profit for each segment for the three and six months ended September 30, 2016 (amounts in thousands): Three Months Ended Six Months Ended September 30, 2016 September 30, 2016 Net Sales Gross Profit Net Sales Gross Profit Semiconductor products $ 847,694 $ 386,951 $ 1,626,517 $ 714,853 Technology licensing 23,670 23,670 44,258 44,258 Total $ 871,364 $ 410,621 $ 1,670,775 $ 759,111 The following table represents net sales and gross profit for each segment for the three and six months ended September 30, 2015 (amounts in thousands): Three Months Ended Six Months Ended September 30, 2015 September 30, 2015 Net Sales Gross Profit Net Sales Gross Profit Semiconductor products $ 518,216 $ 277,775 $ 1,028,905 $ 563,529 Technology licensing 23,175 23,175 46,438 46,438 Total $ 541,391 $ 300,950 $ 1,075,343 $ 609,967

Investments (Tables)

Investments (Tables)	6 Months Ended
	Sep. 30, 2016
Investments [Abstract]
Summary of available-for-sale securities	The following is a summary of available-for-sale securities at September 30, 2016 (amounts in thousands): Available-for-sale Securities Adjusted Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Marketable equity securities $ 2,140 $ — $ (1,292 ) $ 848 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 $ 471,485 $ 447 $ (99 ) $ 471,833
Summary of available-for-sale securities in a continuous unrealized loss position	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 the length of time that the individual securities have been in a continuous unrealized loss position (amounts in thousands): September 30, 2016 Less than 12 Months 12 Months or Greater Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss Marketable equity securities $ 848 $ (1,292 ) $ — $ — $ 848 $ (1,292 ) 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 — $ 148,562 $ (99 ) $ 1,000 $ — $ 149,562 $ (99 )

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Sep. 30, 2016
Fair Value, Assets, Liabilities and Stockholders' Equity Measured on Recurring Basis [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	Assets measured at fair value on a recurring basis at September 30, 2016 are as follows (amounts in thousands): Quoted Prices in Active Markets for Identical Instruments (Level 1) Significant Other Observable Inputs (Level 2) Total Balance Assets Cash and cash equivalents: Money market mutual funds $ 41,494 $ — $ 41,494 Deposit accounts — 448,494 448,494 Short-term investments: Marketable equity securities 848 — 848 Total assets measured at fair value $ 42,342 $ 448,494 $ 490,836 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) 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

Fair Value of Financial Instr41

Fair Value of Financial Instruments (Tables)	6 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Carrying Amounts and Fair Values of Subordinated Convertible Debentures [Table Text Block]	The following table shows the carrying amounts and fair values of the Company’s senior and junior subordinated convertible debentures as of September 30, 2016 and March 31, 2016 (amounts in thousands). As of September 30, 2016 , the carrying amounts of the Company's senior and junior subordinated convertible debentures have been reduced by debt issuance costs of $ 17.5 million and $ 2.3 million , respectively. As of March 31, 2016 , the carrying amounts of the Company's senior and junior subordinated convertible debentures have been reduced by debt issuance costs of $ 18.4 million and $ 2.4 million , respectively. September 30, 2016 March 31, 2016 Carrying Amount Fair Value Carrying Amount Fair Value 1.625% Senior Subordinated Convertible Debentures $ 1,238,731 $ 2,216,539 $ 1,216,313 $ 1,762,088 2.125% Junior Subordinated Convertible Debentures $ 196,868 $ 1,484,805 $ 193,936 $ 1,143,117

Accounts Receivable (Tables)

Accounts Receivable (Tables)	6 Months Ended
	Sep. 30, 2016
Accounts Receivable, Net [Abstract]
Accounts Receivable Schedule	Accounts receivable consists of the following (amounts in thousands): September 30, 2016 March 31, 2016 Trade accounts receivable $ 449,495 $ 289,013 Other 3,931 3,710 Total accounts receivable, gross 453,426 292,723 Less allowance for doubtful accounts 2,384 2,540 Total accounts receivable, net $ 451,042 $ 290,183

Inventories (Tables)

Inventories (Tables)	6 Months Ended
	Sep. 30, 2016
Inventory Disclosure [Abstract]
Components of inventories	The components of inventories consist of the following (amounts in thousands): September 30, 2016 March 31, 2016 Raw materials $ 15,227 $ 12,179 Work in process 292,536 208,283 Finished goods 116,927 86,353 Total inventories $ 424,690 $ 306,815

Property, Plant and Equipment44

Property, Plant and Equipment (Tables)	6 Months Ended
	Sep. 30, 2016
Property, Plant and Equipment [Abstract]
Schedule of Property, Plant and Equipment	Property, plant and equipment consists of the following (amounts in thousands): September 30, 2016 March 31, 2016 Land $ 73,692 $ 63,907 Building and building improvements 500,462 458,379 Machinery and equipment 1,750,646 1,645,617 Projects in process 107,801 99,370 Total property, plant and equipment, gross 2,432,601 2,267,273 Less accumulated depreciation and amortization 1,715,603 1,657,877 Total property, plant and equipment, net $ 716,998 $ 609,396

Intangible Assets and Goodwil45

Intangible Assets and Goodwill (Tables)	6 Months Ended
	Sep. 30, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	Intangible assets consist of the following (amounts in thousands): September 30, 2016 Gross Amount Accumulated Amortization Net Amount Core and developed technology $ 1,813,689 $ (347,137 ) $ 1,466,552 Customer-related 909,141 (258,151 ) 650,990 Trademarks and trade names 11,700 (8,604 ) 3,096 Backlog 28,300 (14,150 ) 14,150 In-process technology 186,067 — 186,067 Distribution rights 5,580 (5,324 ) 256 Other 1,805 (210 ) 1,595 Total $ 2,956,282 $ (633,576 ) $ 2,322,706 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
Projected Amortization Expense	The following is an expected amortization schedule for the intangible assets for the remainder of fiscal 2017 through fiscal 2021, absent any future acquisitions or impairment charges (amounts in thousands): Year ending March 31, Projected Amortization Expense 2017 $170,507 2018 492,584 2019 364,138 2020 314,558 2021 257,223
Goodwill Activity	Goodwill activity for the six months ended September 30, 2016 was as follows (amounts in thousands): Semiconductor Products Reporting Unit Technology Licensing Reporting Unit Balance at March 31, 2016 $ 993,452 $ 19,200 Additions due to the acquisition of Atmel 1,372,102 — Adjustments due to the acquisition of Micrel (14 ) — Balance at September 30, 2016 $ 2,365,540 $ 19,200

Income Taxes (Tables)

Income Taxes (Tables)	6 Months Ended
	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Schedule of Unrecognized Tax Benefits	The following tables summarize the activity related to the Company's gross unrecognized tax benefits for the six months ended September 30, 2016 and the year ended March 31, 2016 (amounts in thousands): Six Months Ended September 30, 2016 Balance at March 31, 2016 $ 220,669 Increases related to acquisitions 194,018 Decreases related to settlements with tax authorities (7,654 ) Decreases related to statute of limitation expirations (1,338 ) Increases related to current year tax positions 15,796 Decreases related to prior year tax positions (134 ) Balance at September 30, 2016 $ 421,357 Year Ended March 31, 2016 Balance at March 31, 2015 $ 170,654 Increases related to acquisitions 46,245 Decreases related to settlements with tax authorities (7,954 ) Decreases related to statute of limitation expirations (4,591 ) Increases related to current year tax positions 16,315 Balance at March 31, 2016 $ 220,669

Pension Plans (Tables)

Pension Plans (Tables)	6 Months Ended
	Sep. 30, 2016
Compensation and Retirement Disclosure [Abstract]
Schedule of Net Benefit Costs	The aggregate net pension expense relating to these two plans are as follows (amounts in thousands): September 30, 2016 Three Months Ended Six Months Ended Service costs $ 363 $ 727 Interest costs 241 484 Amortization of actuarial loss 64 129 Settlements — 231 Net pension period cost $ 668 $ 1,571
Schedule of Changes in Projected Benefit Obligations	The change in projected benefit obligation and the accumulated benefit obligation, were as follows (amounts in thousands): Projected benefit obligation at April 4, 2016 $ 40,313 Service cost 727 Interest cost 484 Settlements 231 Actuarial losses (gains) 12,060 Benefits paid (216 ) Foreign currency exchange rate changes (55 ) Projected benefit obligation at September 30, 2016 $ 53,544 Accumulated benefit obligation at September 30, 2016 48,130
Schedule of Assumptions Used	Actuarial assumptions used to determine benefit obligations for the plans were as follows at September 30, 2016 : Assumed discount rate 0.77% - 1.14% Assumed compensation rate of increase 3.00%
Schedule of Expected Benefit Payments	Future estimated expected benefit payments for the remainder of fiscal 2017 through 2026 are as follows (amounts in thousands): Fiscal Year Ending March 31, Expected Benefit Payments 2017 $ 483 2018 792 2019 985 2020 913 2021 1,198 2022 through 2026 9,185 Total $ 13,556

Comprehensive Income (Loss) (Ta

Comprehensive Income (Loss) (Tables)	6 Months Ended
	Sep. 30, 2016
Equity [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	The following table presents the changes in the components of accumulated other comprehensive income (loss) (AOCI), net of tax, for the six months ended September 30, 2016 (amounts in thousands): Unrealized holding gains (losses) available-for-sale securities Defined benefit pension plans Foreign Currency Total Accumulated other comprehensive income (loss) at March 31, 2016 $ 348 $ 44 $ (3,749 ) $ (3,357 ) Other comprehensive loss before reclassifications (1,729 ) (8,330 ) (2,569 ) (12,628 ) Amounts reclassified from accumulated other comprehensive loss 89 — — 89 Net other comprehensive loss (1,640 ) (8,330 ) (2,569 ) (12,539 ) Accumulated other comprehensive loss at September 30, 2016 $ (1,292 ) $ (8,286 ) $ (6,318 ) $ (15,896 )
Reclassification out of Accumulated Other Comprehensive Income	The table below details where reclassifications of realized transactions out of AOCI are recorded on the condensed consolidated statements of operations (amounts in thousands): Three Months Ended Six Months Ended September 30, September 30, Description of AOCI Component 2016 2015 2016 2015 Related Statement of Income Line Unrealized (losses) gains on available-for-sale securities $ (7 ) $ 6 $ (89 ) $ 13,965 Other income

Share-Based Compensation (Table

Share-Based Compensation (Tables)	6 Months Ended
	Sep. 30, 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): Three Months Ended Six Months Ended September 30, September 30, 2016 2015 2016 2015 Cost of sales $ 4,100 (1) $ 2,398 (1) $ 11,997 (1) $ 4,055 (1) Research and development 10,171 8,670 27,688 15,768 Selling, general and administrative 10,119 11,958 44,284 17,315 Pre-tax effect of share-based compensation 24,390 23,026 83,969 37,138 Income tax benefit 8,358 8,574 29,246 12,106 Net income effect of share-based compensation $ 16,032 $ 14,452 $ 54,723 $ 25,032 (1) During the three and six months ended September 30, 2016 , $2.7 million and $5.5 million , respectively, of share-based compensation expense was capitalized to inventory. The amount of share-based compensation included in cost of sales during the three months ended September 30, 2016 included $4.1 million of previously capitalized share-based compensation expense in inventory that was sold. The amount of share-based compensation included in cost of sales during the six months ended September 30, 2016 included $7.8 million of previously capitalized share-based compensation expense in inventory that was sold and $4.2 million of share-based compensation expense related to the Company's acquisition of Atmel that was not previously capitalized to inventory. During the three and six months ended September 30, 2015 , $1.8 million and $3.6 million , respectively, of share-based compensation expense was capitalized to inventory and $2.4 million and $4.1 million , respectively, of previously capitalized share-based compensation expense in inventory was sold.

Net Income (Loss) Per Common 50

Net Income (Loss) Per Common Share From Continuing Operations Attributable to Microchip Technology Stockholders (Tables)	6 Months Ended
	Sep. 30, 2016
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	The following table sets forth the computation of basic and diluted net income (loss) per common share from continuing operations attributable to Microchip Technology stockholders (in thousands, except per share amounts): Three Months Ended Six Months Ended September 30, September 30, 2016 2015 2016 2015 Net income (loss) from continuing operations attributable to Microchip Technology $ 35,574 $ 64,899 $ (73,651 ) $ 195,566 Weighted average common shares outstanding 215,524 204,275 214,935 203,254 Dilutive effect of stock options and RSUs 4,465 3,065 — 3,228 Dilutive effect of 2037 junior subordinated convertible debentures 13,971 9,759 — 10,451 Weighted average common and potential common shares outstanding 233,960 217,099 214,935 216,933 Basic net income (loss) per common share from continuing operations attributable to Microchip Technology stockholders $ 0.17 $ 0.32 $ (0.34 ) $ 0.96 Diluted net income (loss) per common share from continuing operations attributable to Microchip Technology stockholders $ 0.15 $ 0.30 $ (0.34 ) $ 0.90

Recently Issued Accounting Pr51

Recently Issued Accounting Pronouncements (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Mar. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other assets	$ 90,394	$ 79,393
Total assets	7,074,396	5,537,883
Senior convertible debentures	1,238,731	1,216,313
Junior convertible debentures	196,868	193,936
Long-term line of credit	1,669,834	1,043,156
Total liabilities and stockholder's equity	$ 7,074,396	5,537,883
As Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other assets		109,025
Total assets		5,567,515
Senior convertible debentures		1,234,733
Junior convertible debentures		196,304
Long-term line of credit		1,052,000
Total liabilities and stockholder's equity		5,567,515
Adjustments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other assets		(29,632)
Total assets		(29,632)
Senior convertible debentures		(18,420)
Junior convertible debentures		(2,368)
Long-term line of credit		(8,844)
Total liabilities and stockholder's equity		(29,632)
As Adjusted
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other assets		79,393
Total assets		5,537,883
Senior convertible debentures		1,216,313
Junior convertible debentures		193,936
Long-term line of credit		1,043,156
Total liabilities and stockholder's equity		5,537,883
Accounting Standards Update 2016-09, Forfeiture Rate Component | Additional Paid-in Capital | New Accounting Pronouncement, Early Adoption, Effect
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of new accounting principle in period of adoption		(2,000)
Accounting Standards Update 2016-09, Forfeiture Rate Component | Retained Earnings | New Accounting Pronouncement, Early Adoption, Effect
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of new accounting principle in period of adoption		2,000
Accounting Standards Update 2016-09, Forfeiture Rate Component, Share-based Payment Award Component | New Accounting Pronouncement, Early Adoption, Effect
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred income tax assets, net		2,300
Accounting Standards Update 2016-09, Forfeiture Rate Component, Share-based Payment Award Component | Retained Earnings | New Accounting Pronouncement, Early Adoption, Effect
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of new accounting principle in period of adoption		2,300
Accounting Standards Update 2016-09, Excess Tax Benefit Component | New Accounting Pronouncement, Early Adoption, Effect
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred income tax assets, net		47,200
Accounting Standards Update 2016-09, Excess Tax Benefit Component | Retained Earnings | New Accounting Pronouncement, Early Adoption, Effect
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of new accounting principle in period of adoption		$ 47,200

Business Acquisitions (Narrativ

Business Acquisitions (Narrative) (Details) - USD ($) $ in Thousands, shares in Millions	Apr. 04, 2016	Aug. 03, 2015	Sep. 30, 2016	Sep. 30, 2016	Jun. 30, 2016
Atmel Corporation
Business Acquisition [Line Items]
Cash paid for shares	$ 2,980,000
Shares issued as part of acquisition	10.1
Value of shares issued as part of acquisition	$ 486,100
Transaction and other fees incurred in transaction	14,900
Non cash consideration of certain share-based payment awards	7,500
Total consideration transferred	3,470,000
Payments to acquire businesses portion funded by foreign subsidiaries cash balances	2,040,000
Payments to acquire businesses portion funded by additional lIne of credit borrowings	940,000
Net deferred tax liability for future amortization expense of acquired intangible assets	$ 159,600
Revenue of acquiree included in statement of income since the acquisition date			$ 274,100	$ 493,100
Net loss of acquiree included in statements of income since the acquisition date			95,800	259,400
Net deferred tax assets acquired in a business combination			$ 49,360	$ 49,360	$ 49,466
Micrel Incorporated
Business Acquisition [Line Items]
Cash paid for shares		$ 430,000
Shares issued as part of acquisition		8.6
Non cash consideration of certain share-based payment awards		$ 4,100
Total consideration transferred		816,200
Net deferred tax liability for future amortization expense of acquired intangible assets		99,700
Consideration transferred. cash paid for vested employee stock awards		13,100
Net deferred tax assets acquired in a business combination		$ 11,400

Business Acquisitions (Schedule

Business Acquisitions (Schedule of Purchase Price Allocation) (Details) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Aug. 03, 2015
Business Acquisition [Line Items]
Goodwill	$ 2,384,740		$ 1,012,652
Atmel Corporation
Business Acquisition [Line Items]
Cash and cash equivalents	230,266	$ 230,266
Accounts receivable	135,427	135,427
Inventories	335,163	333,208
Prepaid expenses and other current assets	28,360	28,360
Assets held for sale	24,394	24,394
Property, plant and equipment, net	129,587	129,587
Goodwill	1,372,102	1,378,317
Purchased intangible assets	1,877,945	1,880,245
Long-term deferred tax assets	49,360	49,466
Other assets	7,535	5,948
Total assets acquired	4,190,139	4,195,218
Accounts payable	(55,686)	(55,686)
Other current liabilities	(119,469)	(119,152)
Long-term line of credit	(192,000)	(192,000)
Deferred tax liabilities	(74,885)	(74,334)
Long-term income tax payable	(168,433)	(174,380)
Other long-term liabilities	(106,688)	(106,688)
Total liabilities assumed	(717,161)	(722,240)
Purchase price allocated	3,472,978	3,472,978
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustments [Abstract]
Inventories	1,955
Goodwill	(6,215)
Purchased intangible assets	(2,300)
Long-term deferred tax asset	(106)
Other assets	1,587
Total assets acquired	(5,079)
Other current liabilities	(317)
Deferred tax liabilities	(551)
Long-term income tax payable	5,947
Total liabilities assumed	$ 5,079
Micrel Incorporated
Business Acquisition [Line Items]
Cash and cash equivalents		99,196
Accounts receivable		14,096
Inventories		73,468
Prepaid expenses and other current assets		10,652
Property, plant and equipment, net		38,491
Goodwill		440,978
Purchased intangible assets		273,500
Long-term deferred tax assets				$ 11,400
Other assets		4,268
Total assets acquired		954,649
Accounts payable		(11,068)
Other current liabilities		(31,552)
Deferred tax liabilities		(88,035)
Long-term income tax payable		(7,637)
Other long-term liabilities		(127)
Total liabilities assumed		(138,419)
Purchase price allocated		$ 816,230

Business Acquisitions (Schedu54

Business Acquisitions (Schedule of Purchased Intangible Assets) (Details) - USD ($) $ in Thousands	Apr. 04, 2016	Aug. 03, 2015	Sep. 30, 2016
Atmel Corporation
Business Acquisition [Line Items]
Useful Life	9 years
Purchased Intangible Assets	$ 1,877,945
Atmel Corporation | Core/developed technology
Business Acquisition [Line Items]
Useful Life	11 years		11 years
Purchased Intangible Assets	$ 1,076,540		$ 1,076,500
Atmel Corporation | In-process technology
Business Acquisition [Line Items]
Purchased Intangible Assets	$ 140,700		$ 140,700
Atmel Corporation | Customer-related
Business Acquisition [Line Items]
Useful Life	6 years		6 years
Purchased Intangible Assets	$ 630,600		$ 630,600
Atmel Corporation | Backlog
Business Acquisition [Line Items]
Useful Life	1 year		1 year
Purchased Intangible Assets	$ 28,300		$ 28,300
Atmel Corporation | Other
Business Acquisition [Line Items]
Useful Life	5 years		5 years
Purchased Intangible Assets	$ 1,805		$ 1,800
Micrel Incorporated
Business Acquisition [Line Items]
Purchased Intangible Assets		$ 273,500
Micrel Incorporated | Core/developed technology
Business Acquisition [Line Items]
Useful Life		10 years
Purchased Intangible Assets		$ 175,800
Micrel Incorporated | In-process technology
Business Acquisition [Line Items]
Purchased Intangible Assets		$ 21,000
Micrel Incorporated | Customer-related
Business Acquisition [Line Items]
Useful Life		5 years
Purchased Intangible Assets		$ 71,100
Micrel Incorporated | Backlog
Business Acquisition [Line Items]
Useful Life		1 year
Purchased Intangible Assets		$ 5,600

Business Acquisitions (Schedu55

Business Acquisitions (Schedule of Proforma Results) (Details) - Atmel Corporation - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Business Acquisition [Line Items]
Net sales	$ 872,034	$ 827,924	$ 1,709,152	$ 1,624,716
Net income (loss) from continuing operations	$ 82,332	$ (78,526)	$ 82,102	$ (150,366)
Basic net income (loss) per common share (in USD per share)	$ 0.38	$ (0.37)	$ 0.38	$ (0.70)
Diluted net income (loss) per common share (in USD per share)	$ 0.35	$ (0.37)	$ 0.35	$ (0.70)

DIscontinued Operations and A56

DIscontinued Operations and Assets Held for Sale (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Mar. 31, 2016
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Net sales	$ 8,035		$ 17,411
Cost of sales	6,939		15,363
Operating expenses	2,946		9,371
Income tax benefit	(195)	$ 0	(1,530)	$ 0
Net loss from discontinued operations	(1,655)	$ 0	(5,793)	$ 0
Disposal Group, Including Discontinued Operation, Classified Balance Sheet Disclosures [Abstract]
Inventories	6,580		6,580
Intangible assets	7,500		7,500
Assets held for sale	$ 14,080		$ 14,080		$ 0

Special Charges (Details)

Special Charges (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Unusual or Infrequent Item [Line Items]
Cash payment for special charges			$ 25.6
Unusual or Infrequent Item
Unusual or Infrequent Item [Line Items]
Other nonrecurring expense	$ 9.5	$ 6.6	$ 31.6	$ 8.2

Segment Information (Details)

Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment reporting information [Line Items]
Net Sales	$ 871,364	$ 541,391	$ 1,670,775	$ 1,075,343
Gross Profit	410,621	300,950	759,111	609,967
Semiconductor products
Segment reporting information [Line Items]
Net Sales	847,694	518,216	1,626,517	1,028,905
Gross Profit	386,951	277,775	714,853	563,529
Technology licensing
Segment reporting information [Line Items]
Net Sales	23,670	23,175	44,258	46,438
Gross Profit	$ 23,670	$ 23,175	$ 44,258	$ 46,438

Investments Summary of Availabl

Investments Summary of Available for Sale (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Mar. 31, 2016
Summary of available-for-sale securities [Line Items]
Available-for-sale, adjusted cost		$ 471,485
Available-for-sale, gross unrealized gain		447
Available-for-sale, gross unrealized loss		(99)
Available-for-sale, estimated fair value		471,833
Government agency bonds
Summary of available-for-sale securities [Line Items]
Available-for-sale, adjusted cost		468,290
Available-for-sale, gross unrealized gain		439
Available-for-sale, gross unrealized loss		(99)
Available-for-sale, estimated fair value		468,630
Corporate bonds and debt
Summary of available-for-sale securities [Line Items]
Available-for-sale, adjusted cost		1,000
Available-for-sale, gross unrealized gain		0
Available-for-sale, gross unrealized loss		0
Available-for-sale, estimated fair value		1,000
Marketable equity securities
Summary of available-for-sale securities [Line Items]
Available-for-sale, adjusted cost	$ 2,140	2,195
Available-for-sale, gross unrealized gain	0	8
Available-for-sale, gross unrealized loss	(1,292)	0
Available-for-sale, estimated fair value	$ 848	$ 2,203

Investments AFS (Details)

Investments AFS (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Mar. 31, 2016
Investments [Abstract]
Short-term Investments		$ 848		$ 353,284
Long-term investments		0		$ 118,549
Available-for-sale securities, gross realized gains (losses), sale proceeds	$ 46,700	$ 470,600	$ 135,800
Available-for-sale securities, gross realized gains			$ 14,000

Investments AFS, Continuous Unr

Investments AFS, Continuous Unrealized Loss Position (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Mar. 31, 2016
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
Accumulated loss, available-for-sale securities in a continuous unrealized loss position, less than twelve months		(99)
Fair value of available-for-sale securities in a continuous unrealized loss position, greater than twelve months		1,000
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		149,562
Accumulated loss, available-for-sale securities in a continuous unrealized loss position		(99)
Marketable equity securities
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	$ 848
Accumulated loss, available-for-sale securities in a continuous unrealized loss position, less than twelve months	(1,292)
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	848
Accumulated loss, available-for-sale securities in a continuous unrealized loss position	$ (1,292)
Government agency bonds
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
Accumulated loss, available-for-sale securities in a continuous unrealized loss position, less than twelve months		(99)
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		148,562
Accumulated loss, available-for-sale securities in a continuous unrealized loss position		(99)
Corporate bonds and debt
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
Accumulated loss, available-for-sale securities in a continuous unrealized loss position, less than twelve months		0
Fair value of available-for-sale securities in a continuous unrealized loss position, greater than twelve months		1,000
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		1,000
Accumulated loss, available-for-sale securities in a continuous unrealized loss position		$ 0

Fair Value Measurements, Measur

Fair Value Measurements, Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Mar. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale, estimated fair value		$ 471,833
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value	$ 490,836	2,564,584
Marketable equity securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale, estimated fair value	848	2,203
Corporate bonds and debt
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale, estimated fair value		1,000
Government agency bonds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale, estimated fair value		468,630
Fair Value, Inputs, Level 1 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value	42,342	1,789,649
Fair Value, Inputs, Level 2 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total assets measured at fair value	448,494	774,935
Cash Equivalents | Money market mutual funds | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash and cash equivalents	41,494	1,787,446
Cash Equivalents | Deposit accounts | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash and cash equivalents	448,494	305,305
Cash Equivalents | Fair Value, Inputs, Level 1 | Money market mutual funds | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash and cash equivalents	41,494	1,787,446
Cash Equivalents | Fair Value, Inputs, Level 1 | Deposit accounts | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash and cash equivalents	0	0
Cash Equivalents | Fair Value, Inputs, Level 2 | Money market mutual funds | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash and cash equivalents	0	0
Cash Equivalents | Fair Value, Inputs, Level 2 | Deposit accounts | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Cash and cash equivalents	448,494	305,305
Short-term Investments | Marketable equity securities | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale, estimated fair value	848	2,203
Short-term Investments | Corporate bonds and debt | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale, estimated fair value		1,000
Short-term Investments | Government agency bonds | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale, estimated fair value		350,081
Short-term Investments | Fair Value, Inputs, Level 1 | Marketable equity securities | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale, estimated fair value	848	2,203
Short-term Investments | Fair Value, Inputs, Level 1 | Corporate bonds and debt | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale, estimated fair value		0
Short-term Investments | Fair Value, Inputs, Level 1 | Government agency bonds | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale, estimated fair value		0
Short-term Investments | Fair Value, Inputs, Level 2 | Marketable equity securities | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale, estimated fair value	$ 0	0
Short-term Investments | Fair Value, Inputs, Level 2 | Corporate bonds and debt | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale, estimated fair value		1,000
Short-term Investments | Fair Value, Inputs, Level 2 | Government agency bonds | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale, estimated fair value		350,081
Other Long-term Investments | Government agency bonds | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale, estimated fair value		118,549
Other Long-term Investments | Fair Value, Inputs, Level 1 | Government agency bonds | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale, estimated fair value		0
Other Long-term Investments | Fair Value, Inputs, Level 2 | Government agency bonds | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available-for-sale, estimated fair value		$ 118,549

Fair Value of Financial Instr63

Fair Value of Financial Instruments (Narrative details) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Mar. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Issuance Costs	$ 7.7	$ 8.8
Senior Subordinated Convertible Debenture Due 2025
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Issuance Costs	17.5	18.4
Junior Subordinated Convertible Debentures Due 2037
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt Issuance Costs	$ 2.3	$ 2.4

Fair Value of Financial Instr64

Fair Value of Financial Instruments (Schedule of carrying amounts and fair values) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Mar. 31, 2016
Carrying Value | Senior Subordinated Convertible Debenture Due 2025
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Disclosure for Subordinated Convertible Debentures	$ 1,238,731	$ 1,216,313
Carrying Value | Junior Subordinated Convertible Debentures Due 2037
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Disclosure for Subordinated Convertible Debentures	196,868	193,936
Estimate of Fair Value Measurement | Senior Subordinated Convertible Debenture Due 2025 | Fair Value, Inputs, Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Disclosure for Subordinated Convertible Debentures	2,216,539	1,762,088
Estimate of Fair Value Measurement | Junior Subordinated Convertible Debentures Due 2037 | Fair Value, Inputs, Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Disclosure for Subordinated Convertible Debentures	$ 1,484,805	$ 1,143,117

Accounts Receivable (Details)

Accounts Receivable (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Mar. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivable amounts	$ 453,426	$ 292,723
Less allowance for doubtful accounts	2,384	2,540
Accounts receivable, net	451,042	290,183
Trade Accounts Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivable amounts	449,495	289,013
Other Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivable amounts	$ 3,931	$ 3,710

Inventories (Details)

Inventories (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Mar. 31, 2016
Inventory [Line Items]
Raw materials	$ 15,227	$ 12,179
Work in process	292,536	208,283
Finished goods	116,927	86,353
Inventory, Net	$ 424,690	$ 306,815

Property, Plant and Equipment67

Property, Plant and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Mar. 31, 2016
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	$ 2,432,601		$ 2,432,601		$ 2,267,273
Less accumulated depreciation and amortization	1,715,603		1,715,603		1,657,877
Property, plant and equipment, net	716,998		716,998		609,396
Depreciation expense	30,000	$ 26,200	61,000	$ 50,900
Land
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	73,692		73,692		63,907
Buildings and building improvements
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	500,462		500,462		458,379
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	1,750,646		1,750,646		1,645,617
Projects in progress
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	$ 107,801		$ 107,801		$ 99,370

Intangible Assets, by Major Cla

Intangible Assets, by Major Class (Details) - USD ($) $ in Thousands	Apr. 04, 2016	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Mar. 31, 2016
Finite-Lived Intangible Assets, Net [Abstract]
Gross Amount		$ 2,956,282		$ 2,956,282		$ 1,075,013
Accumulated Amortization		(633,576)		(633,576)		(468,664)
Net Amount		2,322,706		2,322,706		606,349
In-process technology reaching technological feasibility and reclassified				8,900
Amortization of Intangible Assets		82,800	$ 44,900	165,300	$ 80,600
Impairment of Intangible Assets		0	500	1,984	530
Projected Amortization Expense
Future Amortization Expense, Remainder of Fiscal Year		170,507		170,507
Future Amortization Expense, Year Two		492,584		492,584
Future Amortization Expense, Year Three		364,138		364,138
Future Amortization Expense, Year Four		314,558		314,558
Future Amortization Expense, Year Five		257,223		257,223
Core and developed technology
Finite-Lived Intangible Assets, Net [Abstract]
Gross Amount		1,813,689		1,813,689		724,883
Accumulated Amortization		(347,137)		(347,137)		(255,460)
Net Amount		1,466,552		1,466,552		469,423
Customer-related
Finite-Lived Intangible Assets, Net [Abstract]
Gross Amount		909,141		909,141		278,542
Accumulated Amortization		(258,151)		(258,151)		(200,331)
Net Amount		650,990		650,990		78,211
Trademarks and trade names
Finite-Lived Intangible Assets, Net [Abstract]
Gross Amount		11,700		11,700		11,700
Accumulated Amortization		(8,604)		(8,604)		(7,571)
Net Amount		3,096		3,096		4,129
Backlog
Finite-Lived Intangible Assets, Net [Abstract]
Gross Amount		28,300		28,300
Accumulated Amortization		(14,150)		(14,150)
Net Amount		14,150		14,150
In-process technology
Finite-Lived Intangible Assets, Net [Abstract]
Gross Amount		186,067		186,067		54,308
Accumulated Amortization		0		0		0
Net Amount		186,067		186,067		54,308
Distribution rights
Finite-Lived Intangible Assets, Net [Abstract]
Gross Amount		5,580		5,580		5,580
Accumulated Amortization		(5,324)		(5,324)		(5,302)
Net Amount		256		256		$ 278
Other
Finite-Lived Intangible Assets, Net [Abstract]
Gross Amount		1,805		1,805
Accumulated Amortization		(210)		(210)
Net Amount		1,595		$ 1,595
Minimum
Finite-Lived Intangible Assets, Net [Abstract]
Useful Life				1 year
Minimum expected useful life of finite lived intangible assets (in years)				1 year
Maximum
Finite-Lived Intangible Assets, Net [Abstract]
Useful Life				15 years
Minimum expected useful life of finite lived intangible assets (in years)				15 years
Atmel Corporation
Finite-Lived Intangible Assets, Net [Abstract]
Useful Life	9 years
Purchased Intangible Assets	$ 1,877,945
Minimum expected useful life of finite lived intangible assets (in years)	9 years
Atmel Corporation | Core and developed technology
Finite-Lived Intangible Assets, Net [Abstract]
Useful Life	11 years			11 years
Purchased Intangible Assets	$ 1,076,540			$ 1,076,500
Minimum expected useful life of finite lived intangible assets (in years)	11 years			11 years
Atmel Corporation | Customer-related
Finite-Lived Intangible Assets, Net [Abstract]
Useful Life	6 years			6 years
Purchased Intangible Assets	$ 630,600			$ 630,600
Minimum expected useful life of finite lived intangible assets (in years)	6 years			6 years
Atmel Corporation | Backlog
Finite-Lived Intangible Assets, Net [Abstract]
Useful Life	1 year			1 year
Purchased Intangible Assets	$ 28,300			$ 28,300
Minimum expected useful life of finite lived intangible assets (in years)	1 year			1 year
Atmel Corporation | In-process technology
Finite-Lived Intangible Assets, Net [Abstract]
Purchased Intangible Assets	$ 140,700			$ 140,700
Atmel Corporation | Other
Finite-Lived Intangible Assets, Net [Abstract]
Useful Life	5 years			5 years
Purchased Intangible Assets	$ 1,805			$ 1,800
Minimum expected useful life of finite lived intangible assets (in years)	5 years			5 years
Cost of Sales
Finite-Lived Intangible Assets, Net [Abstract]
Amortization of Intangible Assets		1,000	900	$ 1,900	1,700
Operating Expense
Finite-Lived Intangible Assets, Net [Abstract]
Amortization of Intangible Assets		$ 81,800	$ 44,000	$ 163,400	$ 78,900

Goodwill by Reporting Segment (

Goodwill by Reporting Segment (Details) $ in Thousands	6 Months Ended
	Sep. 30, 2016USD ($)
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 1,012,652
Goodwill, ending balance	2,384,740
Atmel Corporation
Goodwill [Roll Forward]
Goodwill, ending balance	1,372,102
Semiconductor products
Goodwill [Roll Forward]
Goodwill, beginning balance	993,452
Goodwill, ending balance	2,365,540
Semiconductor products | Atmel Corporation
Goodwill [Roll Forward]
Additions due to business combination	1,372,102
Semiconductor products | Micrel Incorporated
Goodwill [Roll Forward]
Adjustments due to purchase accounting adjustments	(14)
Technology licensing
Goodwill [Roll Forward]
Goodwill, beginning balance	19,200
Goodwill, ending balance	19,200
Technology licensing | Atmel Corporation
Goodwill [Roll Forward]
Additions due to business combination	0
Technology licensing | Micrel Incorporated
Goodwill [Roll Forward]
Adjustments due to purchase accounting adjustments	$ 0

Income Tax (Narrative) (Details

Income Tax (Narrative) (Details) - USD ($) $ in Millions	6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Mar. 31, 2016
Income Tax Disclosure [Abstract]
Effective income tax rate (benefit)	(12.40%)	(12.60%)
Unrecognized tax benefits, related to deficiency interest on positions	$ 15.9		$ 2.4
Increase in potential payment of interest on uncertain tax positions due to acquisitions	9.3
Unrecognized tax benefits, income tax penalties accrued	60.7		$ 27.6
The increase in accrued penalties related to uncertain tax positions due to acquisitions	$ 25.6

Income Taxes (Schedule of Unrec

Income Taxes (Schedule of Unrecognized Tax Benefits) (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Sep. 30, 2016	Mar. 31, 2016
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits, Beginning Balance	$ 220,669	$ 170,654
Increases related to acquisitions	194,018	46,245
Decreases related to settlements with tax authorities	(7,654)	(7,954)
Decreases related to statute of limitation expirations	(1,338)	(4,591)
Increases related to current year tax positions	15,796	16,315
Decreases related to prior year tax positions	(134)
Unrecognized Tax Benefits, Ending Balance	$ 421,357	$ 220,669

1.625% Senior Subordinated Co72

1.625% Senior Subordinated Convertible Debentures (Details)	3 Months Ended		6 Months Ended
	Sep. 30, 2016USD ($)$ / shares	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)$ / shares	Sep. 30, 2015USD ($)	Mar. 31, 2016USD ($)	Feb. 28, 2015USD ($)
Debt Instrument [Line Items]
Amortization of debt discount on convertible debentures			$ 24,413,000	$ 23,746,000
Senior Subordinated Convertible Debenture Due 2025
Debt Instrument [Line Items]
Principal amount of senior subordinated convertible debentures						$ 1,725,000,000
Interest rate of senior subordinated convertible debentures	1.625%		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		$ 68.66
Debt instrument, convertible, conversion ratio			1534.37%
Debt instrument, convertible, conversion price | $ / shares	$ 65.17		$ 65.17
Debt instrument, convertible, conversion ratio increase option, initial ratio at issuance			7.2827
Debt instrument, convertible, conversion ratio increase option, adjusted for dividends			7.6718
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			21.4811
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		$ 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		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		564,900,000
Amount of unamortized debt discount of debentures	468,700,000		$ 468,700,000		$ 490,300,000
Remaining period, in years, over which unamortized debt discount will be recognized as non-cash interest expense (in years)			8 years 4 months 18 days
Amortization of debt discount on convertible debentures	10,800,000	$ 10,600,000	$ 21,500,000	21,100,000
Recognized amount of interest expense related to coupon on senior subordinated convertible debentures	$ 7,000,000	$ 7,000,000	$ 14,000,000	$ 14,000,000
Effective interest rate of senior convertible debentures			5.90%

2.125% Junior subordinated co73

2.125% Junior subordinated convertible debentures (Details)	3 Months Ended		6 Months Ended
	Sep. 30, 2016USD ($)$ / shares	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)day$ / shares	Sep. 30, 2015USD ($)	Mar. 31, 2016USD ($)
Debt Instrument [Line Items]
Amortization of debt discount on convertible debentures			$ 24,413,000	$ 23,746,000
Junior Subordinated Convertible Debentures Due 2037
Debt Instrument [Line Items]
Principal amount of junior subordinated convertible debentures	$ 575,000,000		$ 575,000,000
Interest rate of junior subordinated convertible debentures	2.125%		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		$ 34.16
Debt instrument, convertible, threshold trading days | day			20
Debt instrument, convertible, threshold consecutive trading days			30 days
Debt instrument, convertible, threshold percentage of stock price trigger			130.00%
Debt instrument, convertible, conversion ratio			41.6895
Debt instrument, convertible, conversion price | $ / shares	$ 23.99		$ 23.99
Debt instrument, convertible, if-converted value in excess of principal			$ 914,600,000
Long-term debt, contingent payment of interest, percentage			0.50%
Carrying value of equity component of the debentures that were bifurcated into a liability and equity component	$ 411,200,000		$ 411,200,000		$ 411,200,000
Estimated fair value of liability component of debentures at issuance date	163,800,000		163,800,000
Debt discount of estimated fair value of liability component of debentures	411,200,000		411,200,000
Amount of unamortized debt discount of debentures	375,400,000		$ 375,400,000		$ 378,300,000
Remaining period, in years, over which unamortized debt discount will be recognized as non-cash interest expense (in years)			21 years 2 months 15 days
Amortization of debt discount on convertible debentures	1,500,000	$ 1,300,000	$ 2,900,000	2,600,000
Recognized amount of interest expense related to debentures	$ 3,100,000	$ 3,100,000	$ 6,200,000	$ 6,100,000
Effective interest rate of junior subordinated convertible debentures			9.10%
Junior Subordinated Convertible Debentures Due 2037 | Minimum
Debt Instrument [Line Items]
Long-term debt, contingent payment of interest, percentage			0.25%
Debt instrument, convertible, trading price | $ / shares	$ 400		$ 400
Junior Subordinated Convertible Debentures Due 2037 | Maximum
Debt Instrument [Line Items]
Long-term debt, contingent payment of interest, percentage			0.50%
Debt instrument, convertible, trading price | $ / shares	$ 1,500		$ 1,500

Credit facility (Details)

Credit facility (Details)	3 Months Ended		6 Months Ended
	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Mar. 31, 2016USD ($)	Feb. 04, 2015USD ($)	Jun. 27, 2013USD ($)
Line of Credit Facility [Line Items]
Debt Issuance Costs	$ 7,700,000		$ 7,700,000		$ 8,800,000
Interest expense	35,126,000	$ 25,644,000	69,542,000	$ 49,696,000
Credit Agreement Maturity June 27, 2018 [Member]
Line of Credit Facility [Line Items]
Credit agreement maximum borrowing amount							$ 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]
Credit agreement maximum borrowing amount						$ 2,555,000,000
Increase option amount						$ 249,400,000	$ 300,000,000
Interest expense	$ 12,000,000	$ 4,900,000	$ 23,600,000	$ 8,500,000
Short-term Debt, Weighted Average Interest Rate	2.55%		2.55%
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]
Amount of credit agreement borrowings outstanding	$ 1,678,000,000		$ 1,678,000,000		$ 1,052,000,000
Period for leverage ratio to determine interest rate spread			preceding four fiscal quarters
Interest rate spread on overdue principal in event of default (percentage)						2.00%
Interest rate spread on overdue amounts in event of default (percentage)						2.00%
February 2015 Amended Credit Facility with Maturity Dates of June 2018 and February 2020 [Member] | Revolving credit facility [Member] | Debt Instrument Interest Rate Option1 [Member]
Line of Credit Facility [Line Items]
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%
February 2015 Amended Credit Facility with Maturity Dates of June 2018 and February 2020 [Member] | Revolving credit facility [Member] | Debt Instrument Interest Rate Option1 [Member] | Minimum
Line of Credit Facility [Line Items]
Spread on variable rate (percentage)			0.25%
February 2015 Amended Credit Facility with Maturity Dates of June 2018 and February 2020 [Member] | Revolving credit facility [Member] | Debt Instrument Interest Rate Option1 [Member] | Maximum
Line of Credit Facility [Line Items]
Spread on variable rate (percentage)			1.25%
February 2015 Amended Credit Facility with Maturity Dates of June 2018 and February 2020 [Member] | Revolving credit facility [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] | Revolving credit facility [Member] | Debt Instrument Interest Rate Option 2 [Member] | Minimum
Line of Credit Facility [Line Items]
Spread on variable rate (percentage)			1.25%
February 2015 Amended Credit Facility with Maturity Dates of June 2018 and February 2020 [Member] | Revolving credit facility [Member] | Debt Instrument Interest Rate Option 2 [Member] | Maximum
Line of Credit Facility [Line Items]
Spread on variable rate (percentage)			2.25%
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]
Credit agreement maximum borrowing amount						$ 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]
Credit agreement maximum borrowing amount						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]
Credit agreement maximum borrowing amount						$ 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]
Credit agreement maximum borrowing amount	2,774,000,000		$ 2,774,000,000
Increase option amount	219,000,000		219,000,000
Remaining Increase Option Amount	$ 30,400,000		$ 30,400,000
Credit Agreement, Total Leverage Ratio, Temporary Maximum Allowed, First Four Quarters	5		5
Credit Agreement, Total Leverage Ratio, Temporary Maximum Allowed, Next Three Quarters	4.75		4.75
Credit Agreement, Total Leverage Ratio, Maximum	4.50		4.50

Pension Plans (Schedule of Net

Pension Plans (Schedule of Net Pension Expense) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Sep. 30, 2016	Sep. 30, 2016	Sep. 30, 2016
Compensation and Retirement Disclosure [Abstract]
Service costs	$ 363	$ 727	$ 727
Interest costs	241	$ 484	484
Amortization of actuarial loss	64		129
Settlements	0		231
Net pension period cost	$ 668		$ 1,571

Pension Plans (Schedule of Chan

Pension Plans (Schedule of Change in Projected Benefit Obligation) (Details) $ in Thousands	3 Months Ended	6 Months Ended
	Sep. 30, 2016USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2016USD ($)
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Projected benefit obligation at April 4, 2016		$ 40,313
Service costs	$ 363	727	$ 727
Interest costs	241	484	484
Settlements		231
Actuarial losses (gains)		12,060
Benefits paid	(100)	(216)	(200)
Foreign currency exchange rate changes		(55)
Projected benefit obligation at September 30, 2016	53,544	53,544	53,544
Accumulated benefit obligation at September 30, 2016	$ 48,130	$ 48,130	$ 48,130

Pension Plans (Schedule of Actu

Pension Plans (Schedule of Actuarial Assumptions) (Details)	6 Months Ended
	Sep. 30, 2016
Defined Benefit Plan Disclosure [Line Items]
Assumed compensation rate of increase	3.00%
Minimum
Defined Benefit Plan Disclosure [Line Items]
Assumed discount rate	0.77%
Maximum
Defined Benefit Plan Disclosure [Line Items]
Assumed discount rate	1.14%

Pension Plans (Schedule of Esti

Pension Plans (Schedule of Estimated Expected Benefit Payments) (Details) $ in Thousands	Sep. 30, 2016USD ($)
Compensation and Retirement Disclosure [Abstract]
2,017	$ 483
2,018	792
2,019	985
2,020	913
2,021	1,198
2022 through 2026	9,185
Total	$ 13,556

Pension Plans (Narrative) (Deta

Pension Plans (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Sep. 30, 2016	Sep. 30, 2016
Compensation and Retirement Disclosure [Abstract]
Defined benefit pension plan, liabilities	$ 53,500		$ 53,500	$ 53,500
Defined benefit pension plan liabilities, current	600		600	600
Defined benefit pension plan, liabilities, noncurrent	52,900		52,900	52,900
Actuarial losses due to decline in discount rates	2,300			12,800
Actuarial gain due to settlements		$ 700
Expected periodic pension cost in current fiscal year				2,900
Benefits paid	$ 100		$ 216	200
Defined benefit plan expected contributions in current fiscal year				$ 500

Contingencies (Details)

Contingencies (Details) $ in Millions	Sep. 30, 2016USD ($)
Loss Contingencies [Line Items]
Loss contingencies, estimate of possible loss	$ 100
Indemnification Agreement
Loss Contingencies [Line Items]
Loss contingencies, estimate of possible loss	$ 147

Derivative Instruments Foreign

Derivative Instruments Foreign Currency Exchange Rate Risk (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Percentage of company sales denominated in US dollars			98.00%
Loss on foreign currency derivatives recorded in earnings, net	$ 2.9	$ 1.6	$ 2.2	$ 1.2

Comprehensive Income (Loss) (Sc

Comprehensive Income (Loss) (Schedule of Changes in the Components of AOCI) (Details) $ in Thousands	6 Months Ended
	Sep. 30, 2016USD ($)
Changes in the components of AOCI
Accumulated other comprehensive income (loss) at March 31, 2016	$ 2,150,919
Accumulated other comprehensive loss at September 30, 2016	2,519,512
AOCI Attributable to Parent [Member]
Changes in the components of AOCI
Accumulated other comprehensive income (loss) at March 31, 2016	(3,357)
Other comprehensive loss before reclassifications	(12,628)
Amounts reclassified from accumulated other comprehensive loss	89
Other comprehensive loss attributable to Microchip Technology	(12,539)
Accumulated other comprehensive loss at September 30, 2016	(15,896)
Minimum pension liability
Changes in the components of AOCI
Accumulated other comprehensive income (loss) at March 31, 2016	44
Other comprehensive loss before reclassifications	(8,330)
Amounts reclassified from accumulated other comprehensive loss	0
Other comprehensive loss attributable to Microchip Technology	(8,330)
Accumulated other comprehensive loss at September 30, 2016	(8,286)
Foreign Currency
Changes in the components of AOCI
Accumulated other comprehensive income (loss) at March 31, 2016	(3,749)
Other comprehensive loss before reclassifications	(2,569)
Amounts reclassified from accumulated other comprehensive loss	0
Other comprehensive loss attributable to Microchip Technology	(2,569)
Accumulated other comprehensive loss at September 30, 2016	(6,318)
Unrealized holding gains (losses) on available-for-sale securities
Changes in the components of AOCI
Accumulated other comprehensive income (loss) at March 31, 2016	348
Other comprehensive loss before reclassifications	(1,729)
Amounts reclassified from accumulated other comprehensive loss	89
Other comprehensive loss attributable to Microchip Technology	(1,640)
Accumulated other comprehensive loss at September 30, 2016	$ (1,292)

Comprehensive Income (Loss) (83

Comprehensive Income (Loss) (Schedule of Reclassifications of Recognized Transactions out of AOCI) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other income	$ (2,789)	$ (1,696)	$ (779)	$ 15,251
Unrealized holding gains (losses) on available-for-sale securities | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other income	$ (7)	$ 6	$ (89)	$ 13,965

Share-Based Compensation (Detai

Share-Based Compensation (Details) - USD ($) $ in Thousands		Apr. 04, 2016	Sep. 30, 2016		Sep. 30, 2015	Sep. 30, 2016		Sep. 30, 2015
Stock-based compensation expense [Line Items]
Allocated share-based compensation expense			$ 24,390		$ 23,026	$ 83,969		$ 37,138
Income tax benefit			8,358		8,574	29,246		12,106
Net income effect of share-based compensation			16,032		14,452	54,723		25,032
Share-based compensation expense previously capitalized	[1]		4,100
Inventory
Stock-based compensation expense [Line Items]
Amount of share-based compensation expense capitalized to inventory			2,700		1,800	5,500		3,600
Share-based compensation expense previously capitalized	[1]					7,800
Cost of Sales
Stock-based compensation expense [Line Items]
Allocated share-based compensation expense			4,100	[1]	2,398	11,997	[1]	4,055	[1]
Research and development
Stock-based compensation expense [Line Items]
Allocated share-based compensation expense			10,171		8,670	27,688		15,768
Selling, General and Administrative
Stock-based compensation expense [Line Items]
Allocated share-based compensation expense			10,119		$ 11,958	44,284		$ 17,315
Atmel Corporation
Stock-based compensation expense [Line Items]
Allocated share-based compensation expense	[1]		$ 6,200			49,400
Share-based compensation expense previously capitalized	[1]					4,200
Business combination fair value of assumed awards at acquisition date		$ 95,900
Non cash consideration of certain share-based payment awards		7,500
Nonvested awards, compensation cost not yet recognized		$ 88,400
Accelerated compensation cost						$ 37,200
[1]	During the three and six months ended September 30, 2016, $2.7 million and $5.5 million, respectively, of share-based compensation expense was capitalized to inventory. The amount of share-based compensation included in cost of sales during the three months ended September 30, 2016 included $4.1 million of previously capitalized share-based compensation expense in inventory that was sold. The amount of share-based compensation included in cost of sales during the six months ended September 30, 2016 included $7.8 million of previously capitalized share-based compensation expense in inventory that was sold and $4.2 million of share-based compensation expense related to the Company's acquisition of Atmel that was not previously capitalized to inventory. During the three and six months ended September 30, 2015, $1.8 million and $3.6 million, respectively, of share-based compensation expense was capitalized to inventory and $2.4 million and $4.1 million, respectively, of previously capitalized share-based compensation expense in inventory was sold.

Net Income (Loss) Per Common 85

Net Income (Loss) Per Common Share From Continuing Operations Attributable to Microchip Technology Stockholders (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net income (loss) from continuing operations attributable to Microchip Technology	$ 35,574	$ 64,899	$ (73,651)	$ 195,566
Weighted average common shares outstanding	215,524,000	204,275,000	214,935,000	203,254,000
Dilutive effect of stock options and RSUs	4,465,000	3,065,000	0	3,228,000
Dilutive effect of 2037 junior subordinated convertible debentures	13,971,278	9,759,393	0	10,451,083
Weighted average common and potential common shares outstanding	233,960,000	217,099,000	214,935,000	216,933,000
Income (loss) from continuing operations, per basic share (in USD per share)	$ 0.17	$ 0.32	$ (0.34)	$ 0.96
Income (loss) from continuing operations, per diluted share (in USD per share)	$ 0.15	$ 0.30	$ (0.34)	$ 0.90
Number of antidilutive option shares		182,848		47,296
Junior Subordinated Convertible Debentures Due 2037
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of antidilutive option shares			13,068,545
Interest rate of subordinated convertible debentures	2.125%		2.125%
Weighted average conversion price per share used in calculating dilutive effect of convertible debt (amount per share)	$ 24.07	$ 24.87	$ 24.15	$ 24.94
Senior Subordinated Convertible Debenture Due 2025
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Interest rate of subordinated convertible debentures	1.625%		1.625%
Weighted average conversion price per share used in calculating dilutive effect of convertible debt (amount per share)	$ 65.38	$ 67.55	$ 65.60	$ 67.75
Employee Stock Option
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of antidilutive option shares			4,312,066

Stock Repurchase (Details)

Stock Repurchase (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended	12 Months Ended	88 Months Ended
	Sep. 30, 2016	Sep. 30, 2016	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
Stock repurchase program, remaining number of shares authorized to be repurchased						11,400,000	2,500,000
Repurchase of common stock (in shares)	0	0	8,600,000	7,500,000
Value of shares repurchased			$ 363.8	$ 234.7
Treasury stock, number of shares held	21,500,000	21,500,000

Dividends (Details)

Dividends (Details) - USD ($) $ / shares in Units, $ in Millions	Dec. 05, 2016	Nov. 07, 2016	Sep. 06, 2016	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Subsequent Event [Line Items]
Dividends declared per common share (in USD per share)				$ 0.3600	$ 0.3580	$ 0.7195	$ 0.7155
Total amount of dividend payment			$ 77.7			$ 154.9
Dividend per share paid during period			$ 0.3600			$ 0.7195
Subsequent Event
Subsequent Event [Line Items]
Dividends declared per common share (in USD per share)		$ 0.3605
Total amount of dividend payment	$ 80