Finisar (FNSR) 10-K 19 Jun 15 2015 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
In Billions, except Share data, unless otherwise specified	3-May-15	Jun. 12, 2015	Oct. 26, 2014
Document and Entity Information [Abstract]
Entity Registrant Name	FINISAR CORP
Entity Central Index Key	1094739
Current Fiscal Year End Date	2
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	3-May-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	FY
Amendment Flag	FALSE
Entity Common Stock, Shares Outstanding		104,151,047
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$1.60

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	3-May-15	Apr. 27, 2014
In Thousands, unless otherwise specified
Current assets:
Cash and cash equivalents	$197,443	$303,101
Short-term investments	292,748	209,922
Accounts receivable, net of allowance for doubtful accounts of $1,136 at May 3, 2015 and $929 at April 27, 2014	213,234	225,020
Accounts receivable, other	40,650	33,749
Inventories	283,670	259,759
Prepaid expenses and other current assets	36,518	33,022
Total current assets	1,064,263	1,064,573
Property, equipment and improvements, net	315,777	273,328
Purchased intangible assets, net	27,188	34,140
Goodwill	106,736	106,114
Minority investments	2,847	2,117
Other assets	35,071	17,274
Total assets	1,551,882	1,497,546
Current liabilities:
Accounts payable	131,510	119,439
Accrued compensation	24,918	38,541
Other current liabilities	39,239	31,776
Deferred revenue	9,850	16,659
Current portion of convertible debt	0	40,015
Total current liabilities	205,517	246,430
Long-term liabilities:
Convertible debt, net of current portion	221,406	212,253
Other non-current liabilities	21,166	22,804
Total liabilities	448,089	481,487
Commitments and contingencies
Stockholders’ equity:
Preferred stock, $0.001 par value, 5,000,000 shares authorized, no shares issued and outstanding at May 3, 2015 and April 27, 2014	0	0
Common stock, $0.001 par value, 750,000,000 shares authorized, 104,131,817 shares issued and outstanding at May 3, 2015 and 97,281,665 shares issued and outstanding at April 27, 2014	104	97
Additional paid-in capital	2,551,114	2,456,110
Accumulated other comprehensive income	861	20,025
Accumulated deficit	-1,448,286	-1,460,173
Total stockholders' equity	1,103,793	1,016,059
Total liabilities and stockholders’ equity	$1,551,882	$1,497,546

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS (Parentheticals) (USD $)	3-May-15	Apr. 27, 2014
In Thousands, except Share data, unless otherwise specified
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$1,136	$929
Preferred stock, par value	$0.00	$0.00
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	$0.00	$0.00
Common stock, shares authorized	750,000,000	750,000,000
Common stock, shares issued	104,131,817	97,281,665
Common stock, shares outstanding	104,131,817	97,281,665

CONSOLIDATED_STATEMENTS_OF_OPE

CONSOLIDATED STATEMENTS OF OPERATIONS (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	3-May-15	Apr. 27, 2014	Apr. 28, 2013
Income Statement [Abstract]
Revenues	$1,250,944	$1,156,833	$934,335
Cost of revenues	888,573	754,773	662,094
Amortization of acquired developed technology	5,739	5,061	7,044
Impairment of long-lived assets	5,722	0	8,156
Gross profit	350,910	396,999	257,041
Operating expenses:
Research and development	202,089	183,355	158,784
Sales and marketing	46,178	46,547	42,347
General and administrative	72,856	53,214	45,337
Amortization of purchased intangibles	2,948	2,468	3,640
Impairment of long-lived assets	45	0	12,488
Total operating expenses	324,116	285,584	262,596
Income (loss) from operations	26,794	111,415	-5,555
Interest income	1,811	1,319	755
Interest expense	-12,022	-5,547	-2,589
Other income (expense), net	4,099	7,234	-449
Income (loss) before income taxes and non-controlling interest	20,682	114,421	-7,838
Provision for income taxes	8,795	2,884	227
Consolidated net income (loss)	11,887	111,537	-8,065
Adjust for net loss attributable to non-controlling interest	0	250	2,611
Net income (loss) attributable to Finisar Corporation	$11,887	$111,787	($5,454)
Net income (loss) per share attributable to Finisar Corporation common stockholders:
Basic (in usd)	$0.12	$1.16	($0.06)
Diluted (in usd)	$0.11	$1.09	($0.06)
Shares used in computing net income (loss) per share:
Basic (in shares)	101,408	95,979	92,860
Diluted (in shares)	104,970	104,112	92,860

CONSOLIDATED_STATEMENTS_OF_COM

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	3-May-15	Apr. 27, 2014	Apr. 28, 2013
Statement of Comprehensive Income [Abstract]
Consolidated net income (loss)	$11,887	$111,537	($8,065)
Other comprehensive loss, net of tax:
Change in cumulative foreign currency translation adjustment	-19,164	-8,500	-195
Total other comprehensive loss, net of tax	-19,164	-8,500	-195
Total comprehensive income (loss)	-7,277	103,037	-8,260
Adjust for comprehensive loss attributable to non-controlling interest, net of tax	0	250	2,611
Comprehensive income (loss) attributable to Finisar Corporation	($7,277)	$103,287	($5,649)

CONSOLIDATED_STATEMENT_OF_STOC

CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY (USD $)	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Total Finisar Stockholders' Equity	Non-controlling Interest
In Thousands, except Share data, unless otherwise specified
Beginning balance at Apr. 30, 2012	$779,845	$91	$2,309,219	$28,720	($1,566,506)	$771,524	$8,321
Beginning balance (in shares) at Apr. 30, 2012		91,451,615
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	-8,065				-5,454	-5,454	-2,611
Other comprehensive loss, net	-195			-195		-195
Issuance of shares pursuant to equity plans, net of tax withholdings (in shares)		1,591,907
Issuance of shares pursuant to equity plans, net of tax withholdings	391	2	389			391
Issuance of shares pursuant to employee stock purchase plan (in shares)		577,136
Issuance of shares pursuant to employee stock purchase plan	6,641	1	6,640			6,641
Issuance of shares for exercise of warrants (in shares)		37,582
Issuance of shares for exercise of warrants	30		30			30
Share-based compensation expense	31,961		31,961			31,961
Employer contribution in defined contribution retirement plan (in shares)		120,380
Employer contribution to defined contribution retirement plan	1,907		1,907			1,907
Issuance of shares upon conversion of convertible debt	0
Ending balance at Apr. 28, 2013	812,515	94	2,350,146	28,525	-1,571,960	806,805	5,710
Ending balance (in shares) at Apr. 28, 2013		93,778,620
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	111,537				111,787	111,787	-250
Other comprehensive loss, net	-8,500			-8,500		-8,500
Issuance of shares pursuant to equity plans, net of tax withholdings (in shares)		2,805,276
Issuance of shares pursuant to equity plans, net of tax withholdings	9,293	3	9,290			9,293
Issuance of shares pursuant to employee stock purchase plan (in shares)		608,946
Issuance of shares pursuant to employee stock purchase plan	7,563	0	7,563			7,563
Share-based compensation expense	37,966		37,966			37,966
Employer contribution in defined contribution retirement plan (in shares)		88,823
Employer contribution to defined contribution retirement plan	2,228		2,228			2,228
Equity component of senior convertible notes, net of allocated issuance costs	48,917		48,917			48,917
Sale of controlling interest	-5,460						-5,460
Issuance of shares upon conversion of convertible debt	0
Ending balance at Apr. 27, 2014	1,016,059	97	2,456,110	20,025	-1,460,173	1,016,059	0
Ending balance (in shares) at Apr. 27, 2014		97,281,665
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	11,887				11,887	11,887	0
Other comprehensive loss, net	-19,164			-19,164		-19,164
Issuance of shares pursuant to equity plans, net of tax withholdings (in shares)		2,453,668
Issuance of shares pursuant to equity plans, net of tax withholdings	-751	3	-754			-751
Issuance of shares pursuant to employee stock purchase plan (in shares)		525,032
Issuance of shares pursuant to employee stock purchase plan	8,584	0	8,584			8,584
Share-based compensation expense	44,600		44,600			44,600
Employer contribution in defined contribution retirement plan (in shares)	122,979	122,979
Employer contribution to defined contribution retirement plan	2,563		2,563			2,563
Issuance of shares upon conversion of convertible debt (in shares)		3,748,473
Issuance of shares upon conversion of convertible debt	40,015	4	40,011			40,015
Ending balance at May. 03, 2015	$1,103,793	$104	$2,551,114	$861	($1,448,286)	$1,103,793	$0
Ending balance (in shares) at May. 03, 2015		104,131,817

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	12 Months Ended
In Thousands, unless otherwise specified	3-May-15	Apr. 27, 2014	Apr. 28, 2013
Operating activities
Net income (loss) attributable to Finisar Corporation	$11,887	$111,787	($5,454)
Adjust for net loss attributable to non-controlling interest	0	-250	-2,611
Consolidated net income (loss)	11,887	111,537	-8,065
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation	82,699	62,013	52,804
Amortization	9,374	8,136	11,336
Stock-based compensation expense	46,613	39,955	33,594
Equity in earnings of equity method investment	-730	-585	0
Gain on sale or retirement of assets and asset disposal groups	-1,955	-8,313	-1,350
Impairment of long-lived assets	5,767	0	20,643
Gain on fair value remeasurement of contingent consideration related to acquisition	0	0	-7,130
Amortization of discount on 0.50% Convertible Senior Notes due 2033	9,153	3,151	0
Changes in operating assets and liabilities:
Accounts receivable	12,238	-74,238	21,971
Inventories	-37,542	-62,864	19,362
Other assets	-17,098	-33,436	1,848
Accounts payable	12,024	33,965	3,015
Accrued compensation	-17,505	4,580	2,390
Deferred revenue	-5,816	5,505	-1,760
Other liabilities	4,488	9,709	-368
Net cash provided by operating activities	113,597	99,115	148,290
Investing activities
Additions to property, equipment and improvements	-149,193	-130,191	-90,622
Proceeds from sale of property and equipment and asset disposal groups	2,477	1,483	2,698
Purchases of short-term investments	-462,935	-209,922	0
Maturities of short-term investments	380,276	0	0
Acquisitions, net of cash acquired	-2,728	-21,155	-21,525
Proceeds from sale of minority investments	1,470	0	10,495
Purchase of intangible assets	0	0	-221
Net cash used in investing activities	-230,633	-359,785	-99,175
Financing activities
Proceeds from term loans	0	4,230	0
Repayments of term loans	-337	-3,676	-3,150
Proceeds from issuance of 0.50% Convertible Senior Notes due 2033, net of issuance costs	0	255,000	0
Proceeds from issuance of shares under equity plans and employee stock purchase plan	11,715	19,141	8,567
Net cash provided by financing activities	11,378	274,695	5,417
Net (decrease) increase in cash and cash equivalents	-105,658	14,025	54,532
Cash and cash equivalents at beginning of year	303,101	289,076	234,544
Cash and cash equivalents at end of year	197,443	303,101	289,076
Supplemental disclosure of cash flow information
Cash paid for interest	2,340	2,067	2,011
Cash paid for taxes	4,984	3,660	2,073
Supplemental disclosure of non-cash transactions
Issuance of common stock upon conversion of 5.0% Convertible Senior Notes due 2029	$40,015	$0	$0

CONSOLIDATED_STATEMENTS_OF_CAS1

CONSOLIDATED STATEMENTS OF CASH FLOWS CONSOLIDATED STATEMENTS OF CASH FLOWS (Parentheticals) (0.5% Convertible Senior Notes Due 2033)	3-May-15	Apr. 27, 2014	Dec. 31, 2013
0.5% Convertible Senior Notes Due 2033
Interest rate	0.50%	0.50%	0.50%

Description_of_Business_and_Ba

Description of Business and Basis of Presentation	12 Months Ended
	3-May-15
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business and Basis of Presentation	Description of Business and Basis of Presentation
	Description of Business
	Finisar Corporation (the “Company”) was incorporated in California in April 1987 and reincorporated in Delaware in November 1999. The Company is a leading provider of optical subsystems and components that are used in data-communication and telecommunication applications. The Company's optical subsystems consist primarily of transmitters, receivers, transceivers, transponders and active optical cables which provide the fundamental optical-electrical or optoelectronic, interface for interconnecting the electronic equipment used in building these networks, including the switches, routers and servers used in wireline networks as well as the antennas and base stations for wireless networks. These products rely on the use of digital and analog RF semiconductor lasers in conjunction with integrated circuits and novel optoelectronic packaging to provide a cost-effective means for transmitting and receiving digital signals over fiber optic cable at speeds ranging from less than 1 gigabit per second, or Gbps, to more than 100 Gbps, over distances of less than 10 meters to more than 2,000 kilometers, using a wide range of network protocols and physical configurations. The Company supplies optical transceivers and transponders that allow point-to-point communications on a fiber using a single specified wavelength or, bundled with multiplexing technologies, can be used to supply multi-terabit per second, or Tbps, bandwidth over several wavelengths on the same fiber. The Company also provides products known as wavelength selective switches, or WSS. In long-haul and metro networks, each fiber may carry 50 to more than100 different high-speed optical channels, each with its own specific optical wavelength. WSS are switches that are used to dynamically switch network traffic from one optical fiber to multiple other fibers without first converting the optical signal to an electronic signal. The wavelength selective feature means that WSS enable any wavelength or combination of wavelengths to be switched from the input fiber to the output fibers. WSS products are sometimes combined with other components and sold as linecards that plug into a system chassis referred to as a reconfigurable optical add/drop multiplexer, or ROADM. The Company's line of optical components consists primarily of packaged lasers and photodetectors for data communication and telecommunication applications. Demand for the Company's products is largely driven by the continually growing need for additional network bandwidth created by the ongoing proliferation of data and video traffic driven by video downloads, Internet protocol TV, social networking, on-line gaming, file sharing, enterprise IP/Internet traffic, cloud computing, and data center virtualization that must be handled by both wireline and wireless networks. Mobile traffic is increasing as a result of proliferation of smartphones, tablet computers, and other mobile devices.
	The Company's manufacturing operations are vertically integrated and include internal production, assembly and test capabilities for the Company's optical subsystem products, as well as key components used in those subsystems. The Company produces many of the key components used in making its products including lasers, photodetectors and integrated circuits, or ICs, designed by its internal IC engineering teams. The Company also has internal assembly and test capabilities that make use of internally designed equipment for the automated testing of the optical subsystems and components.
	The Company sells its products primarily to manufacturers of storage systems, networking equipment and telecommunication equipment such as Alcatel-Lucent, Brocade, Ciena, Cisco Systems, Coriant, EMC, Ericsson, Fujitsu, Hewlett-Packard Company, Huawei, IBM, Juniper, Nokia and QLogic, as well as their contract manufacturers. These customers in turn sell their systems to businesses and to wireline and wireless telecommunication service providers and cable TV operators, collectively referred to as carriers.
	Basis of Presentation
	The consolidated financial statements include the accounts of Finisar Corporation and its controlled subsidiaries (collectively “Finisar” or the “Company”). Non-controlling interest represents the minority shareholders' proportionate share of the net assets and results of operations of the Company's majority-owned subsidiary, Finisar Korea, prior to its sale in the fourth quarter of fiscal 2014. Intercompany accounts and transactions have been eliminated in consolidation.
	Fiscal Periods
	On March 6, 2013, the Company's Board of Directors determined to change the fiscal year of the Company from a year ending on April 30 of each year to a year ending on the Sunday closest to the last day of April in each year. This change was effective with the fiscal year ended April 28, 2013. Fiscal 2015 had 53 weeks, fiscal 2014 had 52 weeks, and fiscal 2016 will have 52 weeks. Prior to this change, the Company maintained its financial records on the basis of a fiscal year ending on April 30, with fiscal quarters ending on the Sunday closest to the end of the period (thirteen-week periods). The first three quarters of fiscal 2015 ended on July 27, 2014, October 26, 2014 and January 25, 2015, respectively. The first three quarters of fiscal 2014 ended on July 28, 2013, October 27, 2013 and January 26, 2014, respectively. The first three quarters of fiscal 2013 ended on July 29, 2012, October 28, 2012 and January 27, 2013, respectively.
	Use of Estimates
	The preparation of financial statements in conformity with U.S. generally accepted accounting principles (U.S. GAAP) requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from these estimates.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	3-May-15
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies
	Revenue Recognition
	The Company’s revenue transactions consist predominately of sales of products to customers. Product revenues are generally recognized in the period in which persuasive evidence of an arrangement exists, title and risk of loss have passed to the customer, generally upon shipment, the price is fixed or determinable, and collectability is reasonably assured.
	At the time revenue is recognized, the Company establishes an accrual for estimated warranty expenses associated with sales, recorded as a component of cost of revenues. The Company’s customers and distributors generally do not have return rights. However, the Company has established an allowance for estimated customer returns, based on historical experience, which is netted against revenue.
	Sales to certain distributors are made under agreements providing distributor price adjustments and rights of return under certain circumstances. Revenue and costs relating to sales to distributors with price protection and rights of return are deferred until products are sold by the distributors to end customers. Revenue recognition depends on notification from the distributor that product has been sold to the end customer. Also reported by the distributor are product resale price, quantity and end customer shipment information, as well as inventory on hand. Deferred revenue on shipments to distributors reflects the effects of distributor price adjustments and the amount of gross margin expected to be realized when distributors sell-through products purchased from us. Accounts receivable from distributors are recognized and inventory is relieved when title to inventories transfers, typically upon shipment from us at which point we have a legally enforceable right to collection under normal payment terms.
	Segment Reporting
	The Financial Accounting Standards Board's (FASB) authoritative guidance regarding segment reporting establishes standards for the way that public business enterprises report information about operating segments in annual financial statements and requires that those enterprises report selected information about operating segments in interim financial reports. It also establishes standards for related disclosures about products and services, geographic areas and major customers. The Company has determined that it operates in one reportable segment comprising optical subsystems and components. Optical subsystems consist primarily of transceivers sold to manufacturers of storage and networking equipment for data communication and telecommunication applications. Optical subsystems also include multiplexers, de-multiplexers and optical add/drop modules for use in telecommunication applications. Optical components consist primarily of packaged lasers and photo-detectors which are incorporated in transceivers for data communication and telecommunication applications.
	Concentrations of Risk
	Financial instruments which potentially subject the Company to concentrations of credit risk include cash and cash equivalents, short-term investment and accounts receivable. The Company invests only in high-quality credit instruments and maintains its cash, cash equivalents and short-term investments with several high-quality credit financial institutions. Deposits held with banks, including those held in foreign branches of global banks, may exceed the amount of insurance provided on such deposits.
	Concentrations of credit risk, with respect to accounts receivable, exist to the extent of amounts presented in the financial statements. Generally, the Company does not require collateral or other security to support customer receivables. The Company performs periodic credit evaluations of its customers and maintains an allowance for potential credit losses based on historical experience and other information available to management. Losses to date have not been material. The Company’s ten largest customers represented 46% and 55% of total accounts receivable at May 3, 2015 and April 27, 2014, respectively. No customers accounted for over 10% of total accounts receivable as of May 3, 2015. Two customers accounted for 12% and 11%, respectively, of total accounts receivable as of April 27, 2014.
	Sales to the Company’s ten largest customers represented 55%, 58% and 54% of total revenues during fiscal 2015, 2014 and 2013, respectively. One customer, Cisco Systems, represented 14%, 17% and 17% of total revenues during fiscal 2015, 2014 and 2013, respectively.
	The Company relies on single and limited suppliers for a number of key components. The Company relies primarily on a limited number of significant independent contract manufacturers for the production of certain key components and subassemblies, including lasers, modulators, and printed circuit boards.
	Included in the Company’s consolidated balance sheet at May 3, 2015 are the net assets of the Company’s operations located at its overseas facilities totaling approximately $470.8 million.
	Foreign Currency Translation
	The functional currency of the Company's foreign subsidiaries is the local currency. Assets and liabilities denominated in foreign currencies are translated using the exchange rate on the balance sheet date. Revenues and expenses are translated using average exchange rates prevailing during the year. Any translation adjustments resulting from this process are shown separately as a component of accumulated other comprehensive income (loss). Foreign currency transaction gains and losses are included in the determination of net income (loss). Included in the determination of net income (loss) for fiscal 2015, 2014 and 2013 were $479,000, $2.5 million and $861,000, respectively, of losses on foreign currency transactions.
	Research and Development
	Research and development expenditures are charged to operations as incurred.
	Shipping and Handling Costs
	The Company records costs related to shipping and handling in cost of sales for all periods presented.
	Cash and Cash Equivalents
	Finisar’s cash equivalents consist of money market funds and highly liquid short-term investments with qualified financial institutions. Finisar considers all highly liquid investments with an original maturity from the date of purchase of three months or less to be cash equivalents.
	Minority Investments
	The Company uses the cost method of accounting for investments in companies that do not have a readily determinable fair value in which it holds an interest of less than 20% and over which it does not have the ability to exercise significant influence. For entities in which the Company holds an interest of greater than 20% or in which the Company does have the ability to exercise significant influence, the Company uses the equity method. Under the equity method of accounting, investments are stated at initial cost and are adjusted for subsequent additional investments and the Company's proportionate share of earnings or losses and distributions. In determining if and when a decline in the market value of these investments below their carrying value is other-than-temporary, the Company evaluates the market conditions, offering prices, trends of earnings and cash flows, price multiples, prospects for liquidity and other key measures of performance. The Company’s policy is to recognize an impairment in the value of its minority equity investments when clear evidence of an impairment exists. Factors considered in this assessment include (a) the completion of a new equity financing that may indicate a new value for the investment, (b) the failure to complete a new equity financing arrangement after seeking to raise additional funds or (c) the commencement of proceedings under which the assets of the business may be placed in receivership or liquidated to satisfy the claims of debt and equity stakeholders. The Company’s minority investments in private companies are generally made in exchange for preferred stock with a liquidation preference that is intended to help protect the underlying value of its investment.
	Fair Value Accounting
	The FASB authoritative guidance regarding fair valuation defines fair value and establishes a framework for measuring fair value and expands the related disclosure requirements. The guidance requires or permits fair value measurements with certain exclusions. It provides that a fair value measurement assumes that the transaction to sell an asset or transfer a liability occurs in the principal market for the asset or liability or, in the absence of a principal market, the most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The guidance establishes a valuation hierarchy for disclosure of the inputs to valuation used to measure fair value. Valuation techniques used to measure fair value under this guidance must maximize the use of observable inputs and minimize the use of unobservable inputs. It describes a fair value hierarchy based on three levels of inputs, of which the first two are considered observable and the last unobservable, that may be used to measure fair value which are the following:
	Level 1 inputs are unadjusted quoted prices in active markets for identical assets or liabilities;
	Level 2 inputs are quoted prices for similar assets and liabilities in active markets or inputs that are observable for the asset or liability, either directly or indirectly through market corroboration, for substantially the full term of the financial instrument; and
	Level 3 inputs are unobservable inputs based on the Company's own assumptions used to measure assets and liabilities at fair value. A financial asset or liability’s classification within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement.
	The Company’s Level 1 assets include instruments valued based on quoted market prices in active markets, which generally include money market funds. The Company classifies items in Level 2 if the investments are valued using observable inputs to quoted market prices, benchmark yields, reported trades, broker/dealer quotes or alternative pricing sources with reasonable levels of price transparency. These investments include commercial papers and certificates of deposit. See Note 11 for additional details regarding the fair value of the Company’s investments.
	Allowance for Doubtful Accounts
	The Company evaluates the collectability of its accounts receivable based on a combination of factors. In circumstances where, subsequent to delivery, the Company becomes aware of a customer’s potential inability to meet its obligations, it records a specific allowance for the doubtful account to reduce the net recognized receivable to the amount the Company reasonably believes will be collected. For all other customers, the Company recognizes an allowance for doubtful accounts based on the length of time the receivables are past due and historical actual bad debt history. A material adverse change in a major customer’s ability to meet its financial obligations to the Company could result in a material reduction in the estimated amount of accounts receivable that can ultimately be collected and an increase in the Company’s general and administrative expenses for the shortfall. Accounts receivable are charged against the allowance for doubtful accounts when identified as fully uncollectable.
	Inventories
	Inventories are stated at the lower of cost (determined on a first-in, first-out basis) or market.
	The Company permanently writes down to its estimated net realizable value the cost of inventory that the Company specifically identifies and considers obsolete or excessive to fulfill future sales estimates. The Company defines obsolete inventory as inventory that will no longer be used in the manufacturing process. Excess inventory is generally defined as inventory in excess of projected usage and is determined using management’s best estimate of future demand, based upon information then available to the Company. The Company also considers: (1) parts and subassemblies that can be used in alternative finished products, (2) parts and subassemblies that are unlikely to be engineered out of the Company’s products, and (3) known design changes which would reduce the Company’s ability to use the inventory as planned. Inventory on hand that is in excess of future demand is written down to its estimated net realizable value. Obligations to purchase inventory acquired by subcontractors based on forecasts provided by the Company are recognized at the time such obligations arise.
	Property, Equipment and Improvements
	Property, equipment and improvements are stated at cost, net of accumulated depreciation and amortization. Property, equipment and improvements are depreciated on a straight-line basis over the estimated useful lives of the assets, generally three years to seven years, except for buildings which are depreciated over 25 years. Land is carried at acquisition cost and not depreciated. Leased land is depreciated over the life of the lease.
	Goodwill and Other Intangible Assets
	Goodwill, purchased technology and other intangible assets resulting from acquisitions are accounted for under the acquisition method. Intangible assets with finite lives are amortized over their estimated useful lives. Amortization of purchased technology and other intangibles has been recorded on a straight-line basis over periods ranging from three to 15 years. Goodwill is assessed for impairment annually or more frequently when an event occurs or circumstances change between annual impairment tests that would more likely than not reduce the fair value of the reporting unit holding the goodwill below its carrying value.
	Accounting for the Impairment of Long-Lived Assets
	The Company periodically evaluates whether changes have occurred to long-lived assets that would require revision of the remaining estimated useful life of the property, improvements and finite-lived intangible assets or render them not recoverable. If such circumstances arise, the Company uses an estimate of the undiscounted value of expected future operating cash flows to determine whether the long-lived assets are impaired. If the aggregate undiscounted cash flows are less than the carrying amount of the assets, the resulting impairment charge to be recorded is calculated based on the excess of the carrying value of the assets over the fair value of such assets, with the fair value determined based on an estimate of discounted future cash flows.
	Restructuring Costs
	The Company recognizes liability for exit and disposal activities when the liability is incurred. Facilities consolidation charges are calculated using estimates and are based upon the remaining future lease commitments for vacated facilities from the date of facility consolidation, net of estimated future sublease income. The estimated costs of vacating these leased facilities are based on market information and trend analysis, including information obtained from third party real estate sources.
	Stock-Based Compensation Expense
	The Company measures and recognizes compensation expense for all stock-based payment awards made to employees and directors including employee stock options, restricted stock units and employee stock purchases under the Company’s Employee Stock Purchase Plan based on estimated fair values. The Company uses the grant-date fair value of its common stock to determine the fair value of restricted stock units. The Company uses the Black-Scholes option pricing model to determine the fair value of stock options and employee stock purchases. The fair value of the portion of the awards that is ultimately expected to vest is recognized as expense in the consolidated statements of operations under the single-option approach on a straight-line basis over the requisite service periods.
	Income Taxes
	The Company uses the liability method to account for income taxes. Under this method, income tax expense is recognized for the amount of taxes payable or refundable for the current year. Deferred tax assets and liabilities are recognized using enacted tax rates for the effect of temporary differences between the book and tax basis of recorded assets and liabilities and their reported amounts, along with net operating loss carryforwards and credit carryforwards. This method also requires that deferred tax assets be reduced by a valuation allowance if it is more likely than not that a portion of the deferred tax asset will not be realized.
	The Company provides for income taxes based upon the geographic composition of worldwide earnings and tax regulations governing each region. The calculation of tax liabilities involves significant judgment in estimating the impact of uncertainties in the application of complex tax laws. Also, the Company’s current effective tax rate assumes that United States income taxes are not provided for the undistributed earnings of non-United States subsidiaries. The Company intends to indefinitely reinvest the earnings of all foreign corporate subsidiaries for past and subsequent accumulated earnings.
	Recent and Pending Adoption of New Accounting Standards
	In May 2014, the FASB, jointly with the International Accounting Standards Board, issued a comprehensive new standard on revenue recognition from contracts with customers. The standard's core principle is that a reporting entity will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In applying this new guidance to contracts within its scope, an entity will: (1) identify the contract(s) with a customer, (2) identify the performance obligation in the contract, (3) determine the transaction price, (4) allocate the transaction price to the performance obligations in the contract, and (5) recognize revenue when (or as) the entity satisfies a performance obligation. Additionally, this new guidance would require significantly expanded disclosures about revenue recognition. Provisions of this new standard are effective for annual reporting periods (including interim reporting periods within those annual periods) beginning after December 15, 2016. In April 2015, the FASB proposed a deferral of this standard's effective date by one year. The proposed deferral allows early adoption at the original effective date. Entities have the option of using either a full retrospective or a modified retrospective approach to adopt this new guidance. The Company is currently evaluating the potential effect on its consolidated financial position, results of operations and cash flows from adoption of this standard.
	From time to time, new accounting pronouncements are issued by the FASB or other standards setting bodies that are adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes the impact of recently issued standards that are not yet effective will not have a material impact on its consolidated financial position, results of operations and cash flows upon adoption.

Net_Income_Loss_Per_Share

Net Income (Loss) Per Share	12 Months Ended
	3-May-15
Earnings Per Share [Abstract]
Net Income (Loss) Per Share	Net Income (Loss) Per Share
	Basic net income (loss) per share has been computed using the weighted-average number of shares of common stock outstanding during the period. Diluted net income (loss) per share has been computed using the weighted-average number of shares of common stock and dilutive potential common shares from stock options and restricted stock units (under the treasury stock method), 5.0% Convertible Senior Notes due 2029 (on an as-if-converted basis), and 0.50% Convertible Senior Notes due 2033 (under the treasury stock method) outstanding during the period.
	The following table presents the calculation of basic and diluted net income (loss) per share:
		Fiscal Years Ended
	(in thousands, except per share amounts)	May 3, 2015			April 27, 2014			April 28, 2013
	Numerator:
	Net income (loss) attributable to Finisar Corporation	$	11,887		$	111,787		$	(5,454	)
	Numerator for basic income (loss) per share	$	11,887		$	111,787		$	(5,454	)
	Effect of dilutive securities:
	Interest expense on 5.0% Convertible Senior Notes due 2029	—			2,157			—
	Numerator for diluted income (loss) per share	$	11,887		$	113,944		$	(5,454	)
	Denominator:
	Denominator for basic income (loss) per share - weighted average shares	101,408			95,979			92,860
	Effect of dilutive securities:
	Stock options and restricted stock units	3,562			4,385			—
	5.0% Convertible Senior Notes due 2029	—			3,748			—
	Dilutive potential common shares	3,562			8,133			—
	Denominator for diluted income (loss) per share	104,970			104,112			92,860
	Net income (loss) per share attributable to Finisar Corporation common stockholders:
	Basic	$	0.12		$	1.16		$	(0.06	)
	Diluted	$	0.11		$	1.09		$	(0.06	)
	The following table presents common shares related to potentially dilutive securities excluded from the calculation of diluted net income (loss) per share as their effect would have been anti-dilutive:
		Fiscal Years Ended
	(in thousands)	May 3, 2015		April 27, 2014			April 28, 2013
	Stock options and restricted stock units	880		1,057			4,599
	Conversion of 5.0% Convertible Senior Notes due 2029	—		—			3,748
	Conversion of 0.50% Convertible Senior Notes due 2033 (1)	—		—			n/a
		880		1,057			8,347
	(1) 0.50% Convertible Senior Notes due 2033 were excluded from the calculation of diluted earnings per share under the treasury stock method since the conversion price exceeded the average market price for the Company's common stock.

Intangible_Assets_Including_Go

Intangible Assets Including Goodwill	12 Months Ended
	3-May-15
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets Including Goodwill	Intangible Assets Including Goodwill
	The following tables reflect intangible assets as of May 3, 2015 and April 27, 2014:
		May 3, 2015
	(in thousands)	Gross Carrying Amount			Accumulated			Net Carrying Amount
					Amortization
	Purchased technology	$	103,859		$	(90,746	)	$	13,113
	Purchased trade name	1,172			(1,172		)	—
	Purchased customer relationships	21,344			(13,648		)	7,696
	Purchased internal use software and backlog	2,816			(1,991		)	825
	Purchased patents	2,620			(966		)	1,654
	Total intangible assets subject to amortization	131,811			(108,523		)	23,288
	In-process research and development	3,900			—			3,900
	Total	$	135,711		$	(108,523	)	$	27,188
		April 27, 2014
	(in thousands)	Gross Carrying Amount			Accumulated			Net Carrying Amount
					Amortization
	Purchased technology	$	102,124		$	(85,007	)	$	17,117
	Purchased trade name	1,172			(1,172		)	—
	Purchased customer relationships	21,344			(11,344		)	10,000
	Purchased internal use software and backlog	2,816			(1,666		)	1,150
	Purchased patents	2,620			(647		)	1,973
	Total intangible assets subject to amortization	130,076			(99,836		)	30,240
	In-process research and development	3,900			—			3,900
	Total	$	133,976		$	(99,836	)	$	34,140
	The amortization expense on intangible assets was $8.7 million, $7.5 million and $10.9 million for fiscal 2015, 2014 and 2013, respectively.
	Estimated amortization expense for each of the next five fiscal years and thereafter as of May 3, 2015 is as follows:
	Year	Amount (in thousands)
	2016	$	8,413
	2017	6,328
	2018	4,218
	2019	2,729
	2020	1,251
	2021 and beyond	349
	Total	$	23,288
	The following table reflects the changes to the carrying amount of goodwill (in thousands):
	Balance at April 28, 2013	$	90,986
	Addition related to an acquisition	15,252
	Goodwill allocated to asset disposal groups	(124		)
	Balance at April 27, 2014	106,114
	Addition related to an acquisition	622
	Balance at May 3, 2015	$	106,736

Investments

Investments	12 Months Ended
	3-May-15
Investments, Debt and Equity Securities [Abstract]
Investments	Investments
	Fixed Income Securities
	The Company's portfolio of fixed income securities consists of commercial paper notes and term bank certificates of deposit. All of the Company's investments in fixed income securities have original maturity (maturity at the purchase date) of less than 12 months. Investments with original maturities of three months or less are classified as cash equivalents. All of the Company's investments in fixed income securities are classified as held-to-maturity since the Company has the positive intent and ability to hold these investments until maturity. These investments are carried at amortized cost.
	The Company's investments in fixed income securities as of May 3, 2015 and April 27, 2014 were as follows:
		May 3, 2015								27-Apr-14
				Gross Unrealized								Gross Unrealized
	(in thousands)	Amortized Cost		Gains		Losses		Fair Value		Amortized Cost		Gains		Losses		Fair Value
	Commercial paper	$	—	$	—	$	—	$	—	$	89,922	$	—	$	—	$	89,922
	Certificates of deposit	292,748		—		—		292,748		120,000		—		—		120,000
	Total	$	292,748	$	—	$	—	$	292,748	$	209,922	$	—	$	—	$	209,922
	Reported as:
	Short-term investments	$	292,748	$	—	$	—	$	292,748	$	209,922	$	—	$	—	$	209,922
	The Company monitors its investment portfolio for impairment on a periodic basis. In order to determine whether a decline in fair value is other-than-temporary, the Company evaluates, among other factors: the duration and extent to which the fair value has been less than the carrying value; the Company's financial condition and business outlook, including key operational and cash flow metrics, current market conditions and future trends in its industry; the Company's relative competitive position within the industry; and the Company's intent and ability to retain the investment for a period of time sufficient to allow for any anticipated recovery in fair value. A decline in the fair value of the security below amortized cost that is deemed other-than-temporary is charged to earnings, resulting in the establishment of a new cost basis for the affected securities. During fiscal 2015, 2014 and 2013 there were no realized gains or losses, and the Company did not recognize any other-than-temporary impairments.
	Minority Investments
	Included in minority investments at both May 3, 2015 and April 27, 2014 was $884,000 representing the carrying value of the Company's minority investment in one privately held company accounted for under the cost method. Additionally, included in minority investments is $2.0 million and $1.2 million at May 3, 2015 and April 27, 2014, respectively, representing the carrying value of the Company's minority investment in one privately held company accounted for under the equity method. At May 3, 2015, the Company had a 19.9% ownership interest in this company. For the year ended May 3, 2015, the Company recorded income of $730,000 representing its share of the net income of this minority investee, which was included in other income (expense), net in the consolidated statements of operations.
	The Company’s investments in these early stage companies were primarily motivated by its desire to gain early access to new technology. The Company’s investments are passive in nature in that the Company generally does not obtain representation on the board of directors of the companies in which it invests.

Inventories

Inventories	12 Months Ended
	3-May-15
Inventory Disclosure [Abstract]
Inventories	Inventories
	Inventories consist of the following (in thousands):	As of
		May 3, 2015		April 27, 2014
	Raw materials	$	57,757	$	52,594
	Work-in-process	146,773		126,181
	Finished goods	79,140		80,984
	Total inventories	$	283,670	$	259,759
	Including: inventory consigned to others	$	34,240	$	31,998

Property_Equipment_and_Improve

Property, Equipment and Improvements	12 Months Ended
	3-May-15
Property, Plant and Equipment [Abstract]
Property, Equipment and Improvements	Property, Equipment and Improvements
	Property, equipment and improvements consist of the following (in thousands):	As of
		May 3, 2015			April 27, 2014
	Land and buildings	$	68,286		$	49,995
	Computer equipment	62,857			55,611
	Office equipment, furniture and fixtures	5,251			5,213
	Machinery and equipment	493,224			435,262
	Leasehold property and improvements	42,099			37,353
	Total	671,717			583,434
	Accumulated depreciation and amortization	(355,940		)	(310,106		)
	Property, equipment and improvements (net)	$	315,777		$	273,328
	During the third quarter of fiscal 2015, the Company recorded a $5.8 million charge for the impairment of long-lived assets (primarily machinery and equipment) due to the projected cash flows associated with these assets not supporting the carrying values of these assets. In accordance with the guidance for the impairment of long-lived assets, these assets were written down to their estimated fair value of zero, which was determined based on an income approach using the discounted cash flow method.

Other_Current_Liabilities

Other Current Liabilities	12 Months Ended
	3-May-15
Other Liabilities Disclosure [Abstract]
Other Current Liabilities	Other Current Liabilities
	Other current liabilities consist of the following (in thousands):	As of
		May 3, 2015		April 27, 2014
	Warranty accrual (Note 18)	$	6,451	$	5,744
	Other liabilities	32,788		26,032
	Total	$	39,239	$	31,776

Debt

Debt	12 Months Ended
	3-May-15
Debt Disclosure [Abstract]
Debt	Debt
	The Company’s convertible debt as of May 3, 2015 and April 27, 2014 is summarized as follows (in thousands):
			Carrying		Interest	Due in
	Description		amount		rate	fiscal year
	As of May 3, 2015
	Convertible Senior Notes due December 2033		221,406		0.50%	2034
	Total		$	221,406
	As of April 27, 2014
	Convertible Senior Notes due October 2029		$	40,015	5.00%	2030
	Convertible Senior Notes due December 2033		$	212,253	0.50%	2034
	Total		$	252,268
	0.50% Convertible Senior Notes Due 2033
	In December 2013, the Company issued and sold $258.8 million in aggregate principal amount of 0.50% Convertible Senior Notes due 2033 (the "2033 Notes") at par. The terms of the 2033 Notes are governed by an indenture by and between the Company and Wells Fargo Bank, National Association, as Trustee. The 2033 Notes will mature on December 15, 2033, unless earlier repurchased, redeemed or converted. The 2033 Notes are senior unsecured and unsubordinated obligations of the Company, and are effectively subordinated to the Company's secured indebtedness and the indebtedness and other liabilities of the Company's subsidiaries. The 2033 Notes bear interest at a rate of 0.5% per year, payable semi-annually in arrears on June 15 and December 15 each year.
	Holders of the 2033 Notes may convert their 2033 Notes at their option prior to the close of business on the business day immediately preceding June 15, 2033 only under the following circumstances: (1) during any fiscal quarter commencing after the fiscal quarter ending on January 26, 2014 (and only during such fiscal quarter), if the last reported sale price of the Company's common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on the last trading day of the immediately preceding fiscal quarter is greater than or equal to 130% of the applicable conversion price on each applicable trading day; (2) during the five business day period after any five consecutive trading day period ("measurement period"), in which the trading price per $1,000 principal amount of the 2033 Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of the Company's common stock and the applicable conversion rate on each such trading day; or (3) upon the occurrence of specified corporate events. On or after June 15, 2033 until the close of business on the second scheduled trading day immediately preceding the maturity date, holders may convert their 2033 Notes at any time, regardless of whether any of the foregoing circumstances have occurred. The conversion rate will initially equal 33.1301 shares of common stock per $1,000 principal amount of the 2033 Notes (which is equivalent to an initial conversion price of approximately $30.18 per share of common stock), subject to adjustment. Upon conversion of a note, the Company will pay or deliver, as the case may be, either cash, shares of its common stock or a combination of cash and shares of its common stock, at the Company's election, as provided in the indenture. If holders elect to convert their 2033 Notes in connection with a "fundamental change" (as defined in the indenture) that occurs on or before December 22, 2018, the Company will, to the extent provided in the indenture, increase the conversion rate applicable to such 2033 Notes ("make-whole feature").
	In the event of a fundamental change, holders will have the option to require the Company to redeem for cash any 2033 Notes held by them at a purchase price equal to 100% of the principal amount of the 2033 Notes plus accrued and unpaid interest to, but excluding, the redemption date. Holders also have the option to require the Company to redeem for cash any 2033 Notes held by them on December 15, 2018, December 15, 2023 and December 15, 2028 at a redemption price equal to 100% of the principal amount of the 2033 Notes plus accrued and unpaid interest to, but excluding, the redemption date. The Company may redeem the 2033 Notes in whole or in part at any time on or after December 22, 2018 at 100% of the principal amount, plus accrued and unpaid interest to, but excluding, the redemption date.
	The Company considered the features embedded in the 2033 Notes, that is, the conversion feature, the holders' put feature, the Company's call feature, and the make-whole feature, and concluded that they are not required to be bifurcated and accounted for separately from the host debt instrument.
	Because of its option to settle conversion of the 2033 Notes in cash, the Company separated the liability and equity components of the 2033 Notes. The carrying amount of the liability component at issuance date of $209.1 million was calculated by estimating the fair value of similar liabilities without a conversion feature. The residual principal amount of the 2033 Notes of $49.6 million was allocated to the equity component. The resulting debt discount is amortized as interest expense. As of May 3, 2015, the remaining debt discount amortization period was 43 months.
	The 2033 Notes consisted of the following:
		As of
	(in thousands)	May 3, 2015
	Liability component:
	Principal	$	258,750
	Unamortized debt discount	(37,344		)
	Net carrying amount of the liability component	$	221,406
	Carrying amount of the equity component	$	49,648
	The Company incurred approximately $3.8 million in transaction costs in connection with the issuance of the 2033 Notes. These costs were allocated to the liability and equity components in proportion to the allocation of proceeds. Transaction costs of $3.1 million, allocated to the liability component, were recognized as a non-current asset and are amortized. Transaction costs of $725,000, allocated to the equity component, were recognized as a reduction of additional paid-in capital.
	The following table sets forth interest expense information for the year ended May 3, 2015 related to the 2033 Notes:
	(in thousands, except percentages)
	Contractual interest expense	$	1,294
	Amortization of the debt discount	9,153
	Amortization of issuance costs	616
	Total interest cost	$	11,063
	Effective interest rate on the liability component	4.87		%
	The Company applies the treasury stock method to determine the potential dilutive effect of the 2033 Notes on net income per share as a result of the Company's intent and stated policy to settle the principal amount of the 2033 Notes in cash.
	5.0% Convertible Senior Notes Due 2029
	In October , 2009, the Company issued and sold $100 million in aggregate principal amount of 5.0% Convertible Senior Notes due 2029 (the "2029 Notes"). The terms of the 2029 Notes were governed by an indenture by and between the Company and Wells Fargo Bank, National Association, as Trustee. The 2029 Notes were scheduled to mature on October 15, 2029, unless earlier repurchased, redeemed or converted. Interest on the 2029 Notes is payable semi-annually in arrears at a rate of 5.0% per annum on each April 15 and October 15, beginning on April 15, 2010. The 2029 Notes were senior unsecured and unsubordinated obligations of the Company, and ranked equally in right of payment with the Company’s other unsecured and unsubordinated indebtedness, but were effectively subordinated to the Company’s secured indebtedness and liabilities to the extent of the value of the collateral securing those obligations, and structurally subordinated to the indebtedness and other liabilities of the Company’s subsidiaries. Holders had the right to convert the 2029 Notes into shares of the Company’s common stock, at their option, at any time prior to the close of business on the trading day before the stated maturity date. The initial conversion rate was 93.6768 shares of Common Stock per $1,000 principal amount of the 2029 Notes (equivalent to an initial conversion price of approximately $10.68 per share of common stock), subject to adjustment upon the occurrence of certain events. Upon conversion of the 2029 Notes, holders were to receive shares of common stock unless the Company obtained consent from a majority of the holders to deliver cash or a combination of cash and shares of common stock in satisfaction of its conversion obligation.
	Holders had the right to require the Company to redeem, for cash, all or part of their 2029 Notes upon a “fundamental change” at a redemption price equal to 100% of the principal amount of the 2029 Notes being redeemed plus accrued and unpaid interest up to, but excluding, the redemption date. Holders also had the right to require the Company to redeem, for cash, any of their 2029 Notes on October 15, 2014, October 15, 2016, October 15, 2019 and October 15, 2024 at a redemption price equal to 100% of the principal amount of the 2029 Notes being redeemed plus accrued and unpaid interest up to, but excluding, the redemption date.
	The Company had the right to redeem the 2029 Notes in whole or in part at a redemption price equal to 100% of the principal amount of the 2029 Notes being redeemed, plus accrued and unpaid interest to, but excluding, the redemption date, at any time on or after October 22, 2014 if the last reported sale price per share of the Company’s common stock exceeds 130% of the conversion price for at least 20 trading days within a period of 30 consecutive trading days ending within five trading days of the date on which the Company provides the notice of redemption.
	The Company considered the embedded derivative in the 2029 Notes, that is, the conversion feature, and concluded that it was indexed to the Company’s common stock and would be classified as equity, were it to be accounted for separately and thus was not required to be bifurcated and accounted for separately from the debt.
	The Company also considered the Company’s call feature and the holders’ put feature in the event of a change in control under the provisions of FASB authoritative guidance, and concluded that they need not be accounted for separately from the debt.
	In fiscal 2011, the Company entered into privately-negotiated agreements with existing holders of the 2029 Notes to exchange an aggregate of approximately $60.0 million principal amount of the 2029 Notes. Following these exchanges, $40.0 million principal amount of the 2029 Notes remained outstanding.
	As explained above, the terms of the 2029 Notes included a provision that allowed the holders to require the Company to redeem any of their notes on October 15, 2014. Accordingly, all $40.0 million of the principal amount of the 2029 Notes outstanding as of April 27, 2014 was classified as a current liability as of that date.
	During October 2014, all holders of the 2029 Notes exercised their rights to exchange their 2029 Notes for 3,748,473 shares of the Company's common stock. All conversions were in accordance with the original terms of the 2029 Notes and no gain or loss was recognized as a result of conversion.

Commitments

Commitments	12 Months Ended
	3-May-15
Commitments and Contingencies Disclosure [Abstract]
Commitments	Commitments
	The Company’s future commitments at May 3, 2015 included minimum payments under non-cancelable operating lease agreements, including operating lease obligations that have been accrued as restructuring charges, as follows (in thousands):
				Payments Due by Period
		Total		Less Than 1 Year		1-3 Years		4-5 Years		After 5 Years
	Operating leases	$	51,695	$	10,573	$	19,426	$	14,390	$	7,306
	Rent expense under the non-cancelable operating leases was approximately $10.7 million, $10.0 million and $9.7 million for the years ended May 3, 2015, April 27, 2014 and April 28, 2013, respectively. The Company subleases a portion of its facilities that it considers to be in excess of its requirements. Sublease income was $218,000, $266,000 and $250,000 for the years ended May 3, 2015, April 27, 2014 and April 28, 2013, respectively. Certain leases have scheduled rent increases which have been included in the above table. Other leases contain provisions to adjust rental rates for inflation during their terms, most of which are based on to-be-published indices. Rents subject to these adjustments are included in the above table based on current rates.

Fair_Value_of_Financial_Instru

Fair Value of Financial Instruments	12 Months Ended
	3-May-15
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments
	The Company's financial instruments measured at fair value on a recurring basis as of May 3, 2015 and April 27, 2014 were as follows:
		May 3, 2015										April 27, 2014
		Carrying		Fair Value								Carrying		Fair Value
	(in thousands)	Amount		Level 1		Level 2		Level 3		Total		Amount		Level 1		Level 2		Level 3		Total
	Money market funds	$	196	$	196	$	—	$	—	$	196	$	30,169	$	30,169	$	—	$	—	$	30,169
	Commercial paper	—		—		—		—		—		89,922		—		89,922		—		89,922
	Certificates of deposit	292,748		—		292,748		—		292,748		120,000		—		120,000		—		120,000
	Total	$	292,944	$	196	$	292,748	$	—	$	292,944	$	240,091	$	30,169	$	209,922	$	—	$	240,091
	The Company's Level 2 financial instruments in the table above are valued using quoted market prices for similar instruments or non-binding market prices that are corroborated by observable market data.
	The Company has not estimated the fair value of its minority investments in two privately held companies as it is not practicable to estimate the fair value of these investments because of the lack of quoted market prices and the inability to estimate fair value without incurring excessive costs. As of May 3, 2015, the carrying value of the Company's minority investments in these privately held companies was $2.8 million, which management believes is not impaired.
	The Company's financial instruments not measured at fair value on a recurring basis as of May 3, 2015 and April 27, 2014 were as follows:
		May 3, 2015										April 27, 2014
		Carrying		Fair Value								Carrying		Fair Value
	(in thousands)	Amount		Level 1		Level 2		Level 3		Total		Amount		Level 1		Level 2		Level 3		Total
	2029 Notes	$	—	$	—	$	—	$	—	$	—	$	40,015	$	104,105	$	—	$	—	$	104,105
	2033 Notes	221,406		264,364		—		—		264,364		212,253		305,325		—		—		305,307
	Total	$	221,406	$	264,364	$	—	$	—	$	264,364	$	252,268	$	409,430	$	—	$	—	$	409,412
	The fair values of the 2029 Notes and 2033 Notes are based on the price in the open market as of or close to the respective balance sheet dates. The difference between the carrying value and the fair value is primarily due to the spread between the conversion price and the market value of the shares underlying the conversion as of each respective balance sheet date.

Stockholders_Equity

Stockholders' Equity	12 Months Ended
	3-May-15
Equity [Abstract]
Stockholders' Equity	Stockholders’ Equity
	Accumulated Other Comprehensive Income
	Cumulative foreign currency translation adjustment was the only component of the accumulated other comprehensive income as of May 3, 2015 and April 28, 2014.
	Common Stock and Preferred Stock
	As of May 3, 2015, Finisar is authorized to issue 750,000,000 shares of $0.001 par value common stock and 5,000,000 shares of $0.001 par value preferred stock. The holder of each share of common stock has the right to one vote and is entitled to receive dividends when and as declared by the Company’s Board of Directors. The Company has never declared or paid dividends on its common stock. The Company has authority to issue up to 5,000,000 shares of preferred stock, $0.001 par value. The preferred stock may be issued in one or more series having such rights, preferences and privileges as may be designated by the Company’s board of directors.
	Common stock subject to future issuance as of May 3, 2015 is as follows:
	Exercise of outstanding stock options	2,283,162
	Vesting of restricted stock awards	6,611,614
	Available for grant under employee stock incentive plan	13,023,873
	Available for grant under employee stock purchase plan	4,249,965
	Total	26,168,614
	Employee Stock Purchase Plan
	In September 2009, the Company’s board of directors adopted the 2009 Employee Stock Purchase Plan (the "ESPP"), which was approved by the stockholders in November 2009. An amended and restated version of ESPP was approved by the Company's board of directors in June 2014 and by the stockholders in September 2014. Under the restated ESPP, 7,000,000 shares of the Company’s common stock have been reserved for issuance, and the term of the ESPP is scheduled to expire on September 1, 2024. The ESPP permits eligible employees to purchase Finisar common stock through payroll deductions, which may not exceed 20% of the employee’s total compensation. Stock may be purchased under the plan at a price equal to 85% of the fair market value of Finisar common stock on either the first or the last day of the offering period, whichever is lower.
	Employee Stock Plans
	In September 1999, Finisar’s 1999 Stock Option Plan was adopted by the board of directors and approved by the stockholders. An amendment and restatement of the 1999 Stock Option Plan, including renaming it the 2005 Stock Incentive Plan (the “2005 Plan”), was approved by the board of directors in September 2005 and by the stockholders in October 2005. An amended and restated version of the 2005 Plan was approved by the Company's board of directors in June 2014 and by the stockholders in September 2014. Under the restated 2005 Plan, a total of 22,500,000 shares of common stock have been reserved for issuance, and the term of the 2005 Plan is scheduled to expire on September 1, 2024. The types of stock-based awards available under the 2005 Plan includes stock options, stock appreciation rights, restricted stock units (“RSUs”) and other stock-based awards which vest upon the attainment of designated performance goals or the satisfaction of specified service requirements or, in the case of certain RSUs or other stock-based awards, become payable upon the expiration of a designated time period following such vesting events. Options generally vest over five years and have a maximum term of 10 years. RSUs generally vest over four years. As of May 3, 2015 and April 27, 2014, no shares were subject to repurchase.
	Stock Options
		Number of Shares			Weighted-Average Exercise Price
	Stock options outstanding as of April 27, 2014	2,621,844			$	14.28
	Stock options exercised	(299,517	)		$	10.27
	Stock options canceled	(39,165	)		$	23.61
	Stock options outstanding as of May 3, 2015	2,283,162			$	14.64
	The total intrinsic value of stock options exercised during fiscal 2015, 2014 and 2013 was $3.4 million, $14.2 million and $4.4 million, respectively. All stock options outstanding as of May 3, 2015 are fully vested and exercisable. The aggregate intrinsic value of stock options outstanding as of May 3, 2015 was $19.5 million. The weighted-average remaining contractual life of stock options outstanding as of May 3, 2015 was 2.7 years.
	Restricted Stock Units
		Number of Shares			Weighted-Average Grant-Date Fair Value
	RSUs unvested as of April 27, 2014	6,516,317			$	15.44
	RSUs granted	2,831,517			$	19.55
	RSUs vested	(2,350,245	)		$	15.42
	RSUs forfeited	(385,975	)		$	17.04
	RSUs unvested as of May 3, 2015	6,611,614			$	17.12
	The weighted-average grant-date fair value of RSUs granted during fiscal 2014 and 2013 was $16.91 and $13.03, respectively. The aggregate intrinsic value of RSUs outstanding as of May 3, 2015 was $138.5 million. The total grant-date fair value of RSUs vested during fiscal 2015, 2014 and 2013 was $36.3 million, $30.4 million and $17.7 million, respectively.
	As of May 3, 2015, the Company had $74.2 million of unrecognized compensation expense, net of estimated forfeitures, related to RSUs grants. These expenses are expected to be recognized over a weighted-average period of 27 months.
	Share-Based Compensation Cost
	The following table sets forth the detailed allocation of the share-based compensation expense for the fiscal years ended May 3, 2015, April 27, 2014 and April 28, 2013 which was reflected in the Company’s operating results (in thousands):
		Fiscal Years Ended
	Share-based compensation expense by caption:	May 3, 2015				April 27, 2014			April 28, 2013
	Cost of revenues	$	9,908			$	8,261		$	6,915
	Research and development	17,764				14,660			10,970
	Sales and marketing	6,251				5,083			3,743
	General and administrative	10,677				9,962			10,333
	Total	$	44,600			$	37,966		$	31,961
		Fiscal Years Ended
	Share-based compensation expense by type of award:	May 3, 2015				April 27, 2014			April 28, 2013
	Stock options	$	—			$	693		$	1,892
	RSUs	41,729				34,506			26,794
	Employee stock purchase rights under ESPP	2,871				2,767			3,275
	Total	$	44,600			$	37,966		$	31,961
	Total share-based compensation cost capitalized as part of inventory was $2.3 million and $1.7 million as of May 3, 2015 and April 27, 2014, respectively.
	The fair value of employee stock purchase rights granted under the ESPP in fiscal 2015, 2014 and 2013 was estimated at the date of grant using the Black-Scholes option-pricing model with the following weighted-average assumptions:
			Fiscal Years Ended
			May 3, 2015			April 27, 2014		April 28, 2013
	Expected term (in years)		0.75			0.75		0.75
	Volatility		34% - 53%			40% - 47%		50% - 53%
	Risk-free interest rate		0.07 - 0.21%			0.01 - 0.13%		0.10 - 0.15%
	Dividend yield		—	%		—	%	—	%
	The expected term of employee stock purchase rights is the average of the remaining purchase periods under each offering period.
	The Company calculated the volatility factor based on the Company’s historical stock prices.
	The Company bases the risk-free interest rate used in the Black-Scholes option-pricing model on constant maturity bonds from the Federal Reserve in which the maturity approximates the expected term.
	The Black-Scholes option-pricing model calls for a single expected dividend yield as an input. The Company has not issued and does not expect to issue any dividends.
	As share-based compensation expense recognized in the consolidated statement of operations for fiscal 2015, 2014 and 2013 is based on awards ultimately expected to vest, it has been reduced for estimated forfeitures. Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. Forfeitures were estimated based on historical experience.
	The weighted-average estimated per share fair value of purchase rights granted under the ESPP in fiscal 2015, 2014 and 2013 was $3.06, $3.69 and $2.81, respectively.
	The Black-Scholes option-pricing model requires the input of highly subjective assumptions, including the expected life of the stock-based award and the stock price volatility. The assumptions listed above represent management’s best estimates, but these estimates involve inherent uncertainties and the application of management judgment. As a result, if other assumptions had been used, recorded share-based compensation expense could have been materially different from that depicted above. In addition, the Company is required to estimate the expected forfeiture rate and only recognize expense for those shares expected to vest. If the actual forfeiture rate is materially different from this estimate, the share-based compensation expense could be materially different.

Employee_Benefit_Plan

Employee Benefit Plan	12 Months Ended
	3-May-15
Compensation and Retirement Disclosure [Abstract]
Employee Benefit Plan	Employee Benefit Plan
	The Company maintains a defined contribution retirement plan under the provisions of Section 401(k) of the Internal Revenue Code which covers all eligible employees. Employees are eligible to participate in the plan on the first day of the calendar year quarter immediately following completion of eligibility requirements as required by the plan.
	Under the plan, each participant may contribute up to 20% of his or her pre-tax gross compensation up to a statutory limit, which is $18,000, $17,500 and $17,500 for calendar year 2015, 2014 and 2013, respectively. All amounts contributed by participants and earnings on participant contributions are fully vested at all times. The Company may contribute an amount equal to one-half of the first 6% of each participant’s contribution. The Company may make the matching contribution in shares of Finisar common stock in lieu of cash. Contributions made in shares will be allocated to each participant’s account using the share price on the date the Company matching contribution is made to the plan.
	The Company made a discretionary matching contribution of 122,979 shares for a total contribution of $2.4 million during the year ended May 3, 2015. The Company’s expenses related to this plan were $2.6 million, $2.2 million and $1.9 million for the fiscal years ended May 3, 2015, April 27, 2014 and April 28, 2013, respectively.

Income_Taxes

Income Taxes	12 Months Ended
	3-May-15
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes
	The components of income tax expense (benefit) consist of the following (in thousands):
		Fiscal Years Ended
		May 3, 2015				April 27, 2014				April 28, 2013
	Current:
	Federal	$	—			$	(385	)		$	—
	State	209				523				(45		)
	Foreign	8,814				5,691				3,896
		9,023				5,829				3,851
	Deferred:
	Federal	(607		)		—				—
	State	(14		)		—				—
	Foreign	393				(2,945		)		(3,624		)
		(228		)		(2,945		)		(3,624		)
	Provision for income taxes	$	8,795			$	2,884			$	227
	Income (loss) before income taxes and non-controlling interest consists of the following (in thousands):
		Fiscal Years Ended
		May 3, 2015				April 27, 2014				April 28, 2013
	U.S.	$	(29,300	)		$	46,314			$	(21,863	)
	Foreign	49,982				68,107				14,025
		$	20,682			$	114,421			$	(7,838	)
	A reconciliation of the income tax provision at the federal statutory rate and the effective rate is as follows:
		Fiscal Years Ended
		May 3, 2015			April 27, 2014			April 28, 2013
	Expected income tax provision (benefit) at U.S. federal statutory rate	35	%		35	%		35	%
	Foreign rate differential	(46.9	)		(18.3	)		38.3
	Share-based compensation expense	29.6			2.5			(45.2	)
	Non-deductible transaction costs	0.5			0.4			(5.8	)
	Non-recurring acquisition-related gain	—			—			31.1
	Valuation allowance	49.1			(21.4	)		(101.0	)
	Intangibles impairment	—			—			36.8
	Research and development credits	(15.0	)		(1.8	)		18.7
	Non-deductible acquisition-related charge	—			—			(6.2	)
	Other	(9.8	)		6.1			(4.6	)
		42.5	%		2.5	%		(2.9	)%
	The components of deferred taxes consist of the following (in thousands):
		Fiscal Years Ended
		May 3, 2015				April 27, 2014				April 28, 2013
	Deferred tax assets:
	Inventory adjustments	$	10,024			$	8,905			$	9,170
	Accruals and reserves	13,081				18,673				14,194
	Tax credits	27,836				24,259				21,869
	Net operating loss carryforwards	101,850				95,952				155,281
	Gain/loss on investments under equity or cost method	8,367				8,843				8,931
	Depreciation and amortization	4,509				2,817				1,915
	Purchase accounting for intangible assets	4,438				5,651				190
	Capital loss carryforward	172				229				563
	Acquired intangibles	8,208				10,142				18,356
	Stock compensation	9,302				8,372				7,917
	Total deferred tax assets	187,787				183,843				238,386
	Valuation allowance	(161,358		)		(153,657		)		(227,889		)
	Net deferred tax assets	26,429				30,186				10,497
	Deferred tax liabilities:
	Acquired intangibles	(5,597		)		(7,252		)		(5,128		)
	Debt discount	(13,862		)		(16,873		)		(1,592		)
	Inventory reserve	(513		)		(457		)		(1,791		)
	Depreciation and amortization	(7,068		)		(5,762		)		(774		)
	Total deferred tax liabilities	(27,040		)		(30,344		)		(9,285		)
	Total net deferred tax assets (liabilities)	$	(611	)		$	(158	)		$	1,212
	Realization of deferred tax assets is dependent upon future taxable earnings, the timing and amount of which are uncertain. Due to U.S. operating losses in previous years and continuing U.S. earnings volatility, management has established and maintained a full valuation allowance for the U.S. deferred tax assets, which comprise approximately 94% of total deferred tax assets, for which management believes it is not more likely than not to be realized in future periods. The Company's valuation allowance increased/(decreased) from the prior year by approximately $7.7 million, $(74.2) million and $5.0 million in fiscal 2015, 2014 and 2013, respectively.
	As of May 3, 2015, approximately $42.7 million of deferred tax assets, which is not included in the above table, was attributable to certain employee stock option deductions. When, and if, realized, the benefit of the tax deduction related to these options will be accounted for as a credit to stockholders' equity rather than as a reduction of the income tax provision.
	At May 3, 2015, the Company had federal, state and foreign net operating loss carryforwards of approximately $375.3 million, $50.1 million and $40.3 million, respectively, and federal and state credit carryforwards of approximately $27.0 million and $20.5 million, respectively. The net operating loss and tax credit carryforwards will expire at various dates beginning in fiscal 2016, if not utilized. Utilization of the Company's U.S. net operating loss and tax credit carryforwards may be subject to a substantial annual limitation due to the ownership change limitations set forth in Internal Revenue Code Section 382 and similar state provisions. Such an annual limitation could result in the expiration of the net operating loss and tax credit carryforwards before utilization.
	The Company's manufacturing operations in Malaysia operate under a tax holiday which will expire at the beginning of fiscal 2017. In fiscal 2015, the aggregate dollar and per share effect of the tax holiday was $5.6 million and $0.05 per share, respectively. As of May 3, 2015, there was no provision for U.S. income taxes for undistributed earnings of the Company's foreign subsidiaries as it is currently the Company's intention to reinvest these earnings indefinitely in operations outside the United States. The cumulative amount of foreign earnings to be permanently re-invested as of May 3, 2015 was approximately $190.6 million. The Company believes it is not practicable to determine the Company's tax liability that may arise in the event of a future repatriation. If repatriated, these earnings could result in a tax expense at the current U.S. federal statutory tax rate of 35%, subject to available net operating losses and other factors. Tax on undistributed earnings may also be reduced by foreign tax credits that may be generated in connection with the repatriation of earnings.
	A reconciliation of the beginning and ending amount of the gross unrecognized tax benefits is as follows (in thousands):
	Fiscal Years Ended
	May 3, 2015				April 27, 2014				April 28, 2013
Beginning balance	$	13,432			$	15,632			$	14,634
Additions for tax positions related to current year	975				712				241
Additions for tax positions related to prior years	246				—				757
Reductions for tax positions related to prior years (lapse of statute of limitations)	—				(2,912		)		—
Ending balance	$	14,653			$	13,432			$	15,632
Excluding the effects of recorded valuation allowances for deferred tax assets, $12.6 million of the unrecognized tax benefits would favorably impact the effective tax rate in future periods if recognized.
It is the Company's belief that no significant changes in the unrecognized tax benefit positions will occur within 12 months from May 3, 2015.
The Company records interest and penalties, if any, related to unrecognized tax benefits in income tax expense. At May 3, 2015, there was no accrued interest or penalties related to uncertain tax positions.
The Company and its subsidiaries are subject to taxation in various state jurisdictions as well as the U.S. The Company's U.S. federal and state income tax returns are generally not subject to examination by the tax authorities for tax years before fiscal 2009. For all federal and state net operating loss and credit carryovers, the statute of limitations does not begin until the carryover items are utilized. The taxing authorities can examine the validity of the carryover items and if necessary, adjustments may be made to the carryover items. The Company's Malaysia, Singapore, China, Australia, Israel and Sweden income tax returns are generally not subject to examination by the tax authorities for tax years before 2009, 2008, 2009, 2010, 2006 and 2009, respectively. The Company's Israel subsidiary received a tax assessment from Israel Tax Authority (ITA) for tax years ended 2005 to 2007. The Company has filed an appeal and anticipates no material tax liability.

Segments_and_Geography_Informa

Segments and Geography Information	12 Months Ended
	3-May-15
Segment Reporting [Abstract]
Segments and Geography Information	Segments and Geography Information
	The Company has one reportable segment consisting of optical subsystems and components. Optical subsystems consist primarily of transmitters, receivers, transceivers, transponders and active optical cables that provide the fundamental optical-electrical, or optoelectronic, interface for interconnecting the electronic equipment used in building communication networks, including the switches, routers and servers used in wireline networks as well as the antennas and base stations for wireless networks. Optical components consists primarily of packaged lasers, receivers and photodetectors for data communication and telecommunication applications and passive optical components used in telecommunication applications.
	The following is a summary of revenues from sales to unaffiliated customers within geographic areas based on the location of the entity purchasing the Company’s products:
		Fiscal Years Ended
	(in thousands)	May 3, 2015		April 27, 2014		April 28, 2013
	United States	$	425,066	$	339,423	$	269,071
	Malaysia	148,258		185,197		183,299
	China	242,916		229,231		171,016
	Rest of the world	434,704		402,982		310,949
	Totals	$	1,250,944	$	1,156,833	$	934,335
	Revenues generated in the United States are all from sales to customers located in the United States.
	The following is a summary of long-lived assets within geographic areas based on the location of the assets:
		As of
	(in thousands)	May 3, 2015		April 27, 2014
	United States	$	122,118	$	110,573
	Malaysia	54,480		56,007
	China	175,580		127,966
	Rest of the world	28,704		32,312
		$	380,882	$	326,858
	The increase in long-lived assets was primarily due to the additions of property and improvements to the Company's manufacturing facilities in China.

Litigation

Litigation	12 Months Ended
	3-May-15
Commitments and Contingencies Disclosure [Abstract]
Litigation	Litigation
	The Company accrues a liability for legal contingencies when it believes that it is both probable that a liability has been incurred and that it can reasonably estimate the amount of the loss. The Company reviews these accruals and adjusts them to reflect ongoing negotiations, settlements, rulings, advice of legal counsel and other relevant information. To the extent new information is obtained and the Company's views on the probable outcomes of claims, suits, assessments, investigations or legal proceedings change, changes in the Company's accrued liabilities would be recorded in the period in which such determination is made. For the matters referenced below, the amount of liability is not probable or the amount cannot be reasonably estimated and, therefore, accruals have not been made. In addition, in accordance with the relevant authoritative guidance, for matters which the likelihood of material loss is at least reasonably possible, the Company provides disclosure of the possible loss or range of loss; however, if a reasonable estimate cannot be made, the Company will provide disclosure to that effect.
	Due to the nature of the Company's business, it is subject to claims alleging infringement by various Company products and services. The Company believes that it has meritorious defenses to the allegations made in its pending cases and intends to vigorously defend these lawsuits; however, it is unable currently to determine the ultimate outcome of these or similar matters. In addition, the Company is a defendant in various litigation matters generally arising out of the normal course of business. Although it is difficult to predict the ultimate outcomes of these cases, the Company believes that it is not reasonably possible that the ultimate outcomes will materially and adversely affect its business, financial position, results of operations or cash flows.
	Class Action and Shareholder Derivative Litigation
	Several securities class action lawsuits related to the Company's March 8, 2011 earnings announcement alleging claims under Sections 10(b) and 20(a) of the Securities Exchange Act of 1934 have been filed in the United States District Court for the Northern District of California on behalf of a purported class of persons who purchased stock between December 1 or 2, 2010 through March 8, 2011. The named defendants are the Company and its Chairman of the Board, Chief Executive Officer and Chief Financial Officer. To date, no specific amount of damages have been alleged. The cases were consolidated, lead plaintiffs were appointed and a consolidated complaint was filed. The Company filed a motion to dismiss the case. On January 16, 2013, the District Court granted the Company's motion to dismiss and granted the lead plaintiffs leave to amend the consolidated complaint. An amended consolidated complaint was filed on February 6, 2013. Thereafter, the Company filed a renewed motion to dismiss the case. On September 30, 2013, the District Court granted the Company's motion and dismissed the case with prejudice. On October 25, 2013, the lead plaintiffs filed a notice of appeal of the District Court's dismissal ruling, and the appeal is pending.
	In addition, two purported shareholder derivative lawsuits related to the Company's March 8, 2011 earnings announcement have been filed in the California Superior Court for the County of Santa Clara, and a third derivative lawsuit has been filed in the United States District Court for the Northern District of California. The complaints assert claims for alleged breach of fiduciary duty, unjust enrichment, and waste on behalf of the Company. Named as defendants are the members of the Company's board of directors, including the Company's Chairman of the Board and Chief Executive Officer, and its Chief Financial Officer. No specific amount of damages has been alleged and, by the derivative nature of the lawsuits, no damages will be alleged, against the Company. The state court cases have been consolidated and a lead plaintiff has been appointed to file a consolidated complaint. The derivative cases were stayed pending a ruling in the federal class action case. Following the September 30 ruling dismissing the class action case, the derivative cases remain stayed, subject to the right of the parties to reinstate them.
	Thomas Swan Litigation
	On February 26, 2013, Thomas Swan & Co. Ltd. filed a complaint for patent infringement in the United States District Court for the Eastern District of Texas against the Company. The complaint alleges that Finisar's WSS products, ROADM line cards containing a Finisar WSS, and Waveshaper products infringe four related Thomas Swan patents. The Company's customer, Fujitsu Network Communications, was added as a co-defendant in this lawsuit. The Company has performed a review of the asserted patents and believes that the patent claims are not infringed and/or are invalid. In October 2014, the parties reached a confidential agreement to settle this lawsuit. The Company evaluated the transaction as a multiple-element arrangement and allocated the one-time payment of $11.0 million that the Company is obligated to make to the plaintiff in connection with the settlement to each identifiable element using its estimates of relative fair values of these elements. The Company determined that the primary benefits of the arrangement are avoided litigation cost and elimination of use of the Company's management and personnel resources, with no material value attributable to future use or benefit. Accordingly, the Company recorded an $11.0 million settlement charge as general and administrative expenses in the consolidated statements of operations for the quarter ended October 26, 2014.
	Mears Technologies Litigation
	On May 6, 2013, Mears Technologies, Inc. filed a complaint for patent infringement in the United States District Court for the Eastern District of Texas against the Company. The complaint alleges that Finisar's WSS products, ROADM line cards containing a Finisar WSS, and Waveshaper products infringe U.S. Patent No. 6,141,361. The Company has performed a review of the asserted patent and believes that the patent claims are not infringed and/or are invalid. On June 17, 2014, the district court issued a claim construction order favorable to the Company. On October 6, 2014, the court denied a motion of the plaintiff to amend its infringement contentions in light of the court’s claim construction ruling.  As a result, the plaintiff has conceded that it is unable to pursue its infringement claims against the Company.  On December 30, 2014, the court granted the Company’s motion for summary judgment of non-infringement.  The plaintiff has indicated that it intends to appeal the court’s claim construction ruling and the court’s denial of the plaintiff’s motion to amend its infringement contentions in light of the court’s claim construction ruling. The Company intends to oppose any such appeal vigorously.  However, if the plaintiff’s appeal is wholly or partially successful, the case would be revived in the United States District Court for the Eastern District of Texas.  If the appeal succeeds and the case resumes, the Company may be liable for substantial damages.  Even if the defense of any resumed case is successful, the Company may incur substantial legal fees and other costs in defending the lawsuit. Further, the lawsuit could divert the efforts and attention of the Company's management and technical personnel, which could harm its business.
	Other
	In the ordinary course of business, the Company is a party to litigation, claims and assessments in addition to those described above. Based on information currently available, management does not believe the impact of these other matters will have a material adverse effect on its business, financial condition, results of operations or cash flows of the Company.

Restructuring_Charges

Restructuring Charges	12 Months Ended
	3-May-15
Restructuring and Related Activities [Abstract]
Restructuring Charges	Restructuring Charges
	During the second quarter of fiscal 2010, the Company recorded restructuring charges of $4.2 million representing non-cancelable payment obligations under the facility lease relating to the abandoned and unused portion of its facility in Allen, Texas.
	The following table summarizes the activities of the restructuring accrual during fiscal 2015 (in thousands):
	Balance as of April 27, 2014	$	2,911
	Cash payments, net of sublease income	(351		)
	Balance as of May 3, 2015	$	2,560
	Of the $2.6 million of remaining accrual, $390,000 is expected to be paid in fiscal 2016 and $2.2 million is expected to be paid out from fiscal 2017 through fiscal 2020.

Warranty

Warranty	12 Months Ended
	3-May-15
Product Warranties Disclosures [Abstract]
Warranty	Warranty
	The Company generally offers a one-year limited warranty for its products. The specific terms and conditions of these warranties vary depending upon the product sold. The Company estimates the costs that may be incurred under its basic limited warranty and records a liability for the amount of such costs at the time revenue is recognized. Factors that affect the Company’s warranty liability include the historical and anticipated rates of warranty claims and cost to repair. The Company periodically assesses the adequacy of its recorded warranty liabilities and adjusts the amounts as necessary.
	Changes in the Company’s warranty liability during the following periods were as follows:
		As of
	(in thousands)	May 3, 2015			April 27, 2014
	Beginning balance	$	5,744		$	4,155
	Additions during the period based on product sold	6,171			5,653
	Additions during the period due to acquisitions	—			515
	Change in estimates	(1,388		)	(2,022		)
	Settlements and expirations	(4,076		)	(2,557		)
	Ending balance	$	6,451		$	5,744

Related_Parties

Related Parties	12 Months Ended
	3-May-15
Related Party Transactions [Abstract]
Related Parties	Related Parties
	During fiscal 2015, the Company paid $140,696 in cash compensation to a company owned by Guy Gertel, the brother of the Chief Executive Officer of the Company, for sales and marketing services. In addition, the Company granted to Mr. Gertel, for no additional consideration, 2,305 restricted stock units with a grant-date fair value of $45,132, which vest as follows: 25% on June 23, 2015 and an additional 25% on each of the next three anniversaries thereafter, to be fully vested on June 23, 2018, subject to him continuing to provide services to Finisar. During fiscal 2014, the Company paid $195,164 in cash compensation to Mr. Gertel's company and granted to Mr. Gertel, for no additional consideration, 4,164 restricted stock units with a grant-date fair value of $66,957, which vest as follows: 25% on June 24, 2014 and an additional 25% on each of the next three anniversaries thereafter, to be fully vested on June 24, 2017, subject to him continuing to provide services to Finisar. During fiscal 2013, the Company paid $216,723 in cash compensation to Mr. Gertel's company and granted to Mr. Gertel, for no additional consideration, 3,814 restricted stock units with a grant-date fair value of $49,086, which vest as follows: 25% on June 18, 2013 and an additional 25% on each of the next three anniversaries thereafter, to be fully vested on June 18, 2016, subject to him continuing to provide services to Finisar. Amounts paid to Mr. Gertel represented values considered by management to be fair and reasonable, reflective of an arm’s length transaction.

Guarantees_and_Indemnification

Guarantees and Indemnifications	12 Months Ended
	3-May-15
Guarantees [Abstract]
Guarantees and Indemnifications	Guarantees and Indemnifications
	Upon issuance of a guarantee, the guarantor must recognize a liability for the fair value of the obligations it assumes under that guarantee. As permitted under Delaware law and in accordance with the Company’s Bylaws, the Company indemnifies its officers and directors for certain events or occurrences, subject to certain limits, while the officer or director is or was serving at the Company’s request in such capacity. The term of the indemnification period is for the officer’s or director’s lifetime. The Company may terminate the indemnification agreements with its officers and directors upon 90 days written notice, but termination will not affect claims for indemnification relating to events occurring prior to the effective date of termination. The maximum amount of potential future indemnification is unlimited; however, the Company has a director and officer liability insurance policy that may enable it to recover a portion of any future amounts paid.
	The Company enters into indemnification obligations under its agreements with other companies in its ordinary course of business, including agreements with customers, business partners, and insurers. Under these provisions the Company generally indemnifies and holds harmless the indemnified party for losses suffered or incurred by the indemnified party as a result of the Company’s activities or the use of the Company’s products. These indemnification provisions generally survive termination of the underlying agreement. In some cases, the maximum potential amount of future payments the Company could be required to make under these indemnification provisions is unlimited.
	The Company believes the fair value of these indemnification agreements is minimal. Accordingly, the Company has not recorded any liabilities for these agreements as of May 3, 2015. To date, the Company has not incurred material costs to defend lawsuits or settle claims related to these indemnification agreements.

Financial_Information_by_Quart

Financial Information by Quarter (Unaudited)	12 Months Ended
	3-May-15
Quarterly Financial Information Disclosure [Abstract]
Financial Information by Quarter (Unaudited)	Financial Information by Quarter (Unaudited)
		Three Months Ended
		3-May-15		January 25, 2015 (1)		October 26, 2014 (2)			27-Jul-14		April 27, 2014 (3)		26-Jan-14		27-Oct-13		July 28, 2013 (4)
		(In thousands, except per share data)
	Revenues	$	320,042	$	306,283	$	296,981		$	327,638	$	306,025	$	294,018	$	290,722	$	266,068
	Gross profit	$	89,217	$	77,953	$	84,921		$	98,819	$	96,564	$	105,689	$	103,373	$	91,373
	Income (loss) from operations	$	10,284	$	3,401	$	(7,259	)	$	20,368	$	21,107	$	33,096	$	30,109	$	27,103
	Income (loss) before non-controlling interest	$	7,327	$	1,678	$	(11,361	)	$	14,243	$	28,683	$	27,068	$	29,951	$	25,835
	Net income (loss) attributable to Finisar Corporation	$	7,327	$	1,678	$	(11,361	)	$	14,243	$	28,750	$	27,061	$	29,965	$	26,011
	Net income (loss) per share attributable to Finisar Corporation common stockholders:
	Basic	$	0.07	$	0.02	$	(0.11	)	$	0.14	$	0.3	$	0.28	$	0.31	$	0.27
	Diluted	$	0.07	$	0.02	$	(0.11	)	$	0.14	$	0.28	$	0.26	$	0.29	$	0.26
	Shares used in computing net income (loss) per share:
	Basic	104,005		103,563		99,621			98,241		96,965		96,394		95,941		94,609
	Diluted	107,535		105,990		99,621			106,036		105,418		104,361		103,696		101,125
	(1) Net income in the third quarter of fiscal 2015 includes a $5.8 million impairment charge for long-lived assets.
	(2) Net loss in the second quarter of fiscal 2015 includes an $11.0 million charge related to the settlement of patent litigation.
	(3) Net income in the fourth quarter of fiscal 2014 includes an $8.2 million gain on divestiture of majority-owned subsidiary, Finisar Korea.
	(4) Net income in the first quarter of fiscal 2014 includes a $6.5 million gain related to the settlement of stock option litigation.

Schedule_II_Consolidated_Valua

Schedule II - Consolidated Valuation and Qualifying Accounts	12 Months Ended
	3-May-15
Valuation and Qualifying Accounts [Abstract]
Schedule II - Consolidated Valuation and Qualifying Accounts	Schedule II — Consolidated Valuation and Qualifying Accounts
		Balance at		Additions			Write-Offs			Balance at
		Beginning		Charged to (Recoveries Offset)						End of
		of Period		Costs and						Period
				Expenses, Net
		(in thousands)
	Allowance for doubtful accounts
	Balance at May 3, 2015	$	929	$	207		$	—		$	1,136
	Balance at April 27, 2014	$	958	$	101		$	(130	)	$	929
	Balance at April 28, 2013	$	1,311	$	(268	)	$	(85	)	$	958

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	3-May-15
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation
	The consolidated financial statements include the accounts of Finisar Corporation and its controlled subsidiaries (collectively “Finisar” or the “Company”). Non-controlling interest represents the minority shareholders' proportionate share of the net assets and results of operations of the Company's majority-owned subsidiary, Finisar Korea, prior to its sale in the fourth quarter of fiscal 2014. Intercompany accounts and transactions have been eliminated in consolidation.
Fiscal Periods	Fiscal Periods
	On March 6, 2013, the Company's Board of Directors determined to change the fiscal year of the Company from a year ending on April 30 of each year to a year ending on the Sunday closest to the last day of April in each year. This change was effective with the fiscal year ended April 28, 2013. Fiscal 2015 had 53 weeks, fiscal 2014 had 52 weeks, and fiscal 2016 will have 52 weeks. Prior to this change, the Company maintained its financial records on the basis of a fiscal year ending on April 30, with fiscal quarters ending on the Sunday closest to the end of the period (thirteen-week periods). The first three quarters of fiscal 2015 ended on July 27, 2014, October 26, 2014 and January 25, 2015, respectively. The first three quarters of fiscal 2014 ended on July 28, 2013, October 27, 2013 and January 26, 2014, respectively. The first three quarters of fiscal 2013 ended on July 29, 2012, October 28, 2012 and January 27, 2013, respectively.
Use of Estimates	Use of Estimates
	The preparation of financial statements in conformity with U.S. generally accepted accounting principles (U.S. GAAP) requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from these estimates.
Revenue Recognition	Revenue Recognition
	The Company’s revenue transactions consist predominately of sales of products to customers. Product revenues are generally recognized in the period in which persuasive evidence of an arrangement exists, title and risk of loss have passed to the customer, generally upon shipment, the price is fixed or determinable, and collectability is reasonably assured.
	At the time revenue is recognized, the Company establishes an accrual for estimated warranty expenses associated with sales, recorded as a component of cost of revenues. The Company’s customers and distributors generally do not have return rights. However, the Company has established an allowance for estimated customer returns, based on historical experience, which is netted against revenue.
	Sales to certain distributors are made under agreements providing distributor price adjustments and rights of return under certain circumstances. Revenue and costs relating to sales to distributors with price protection and rights of return are deferred until products are sold by the distributors to end customers. Revenue recognition depends on notification from the distributor that product has been sold to the end customer. Also reported by the distributor are product resale price, quantity and end customer shipment information, as well as inventory on hand. Deferred revenue on shipments to distributors reflects the effects of distributor price adjustments and the amount of gross margin expected to be realized when distributors sell-through products purchased from us. Accounts receivable from distributors are recognized and inventory is relieved when title to inventories transfers, typically upon shipment from us at which point we have a legally enforceable right to collection under normal payment terms.
Segment Reporting	Segment Reporting
	The Financial Accounting Standards Board's (FASB) authoritative guidance regarding segment reporting establishes standards for the way that public business enterprises report information about operating segments in annual financial statements and requires that those enterprises report selected information about operating segments in interim financial reports. It also establishes standards for related disclosures about products and services, geographic areas and major customers. The Company has determined that it operates in one reportable segment comprising optical subsystems and components. Optical subsystems consist primarily of transceivers sold to manufacturers of storage and networking equipment for data communication and telecommunication applications. Optical subsystems also include multiplexers, de-multiplexers and optical add/drop modules for use in telecommunication applications. Optical components consist primarily of packaged lasers and photo-detectors which are incorporated in transceivers for data communication and telecommunication applications.
Concentrations of Risk	Concentrations of Risk
	Financial instruments which potentially subject the Company to concentrations of credit risk include cash and cash equivalents, short-term investment and accounts receivable. The Company invests only in high-quality credit instruments and maintains its cash, cash equivalents and short-term investments with several high-quality credit financial institutions. Deposits held with banks, including those held in foreign branches of global banks, may exceed the amount of insurance provided on such deposits.
	Concentrations of credit risk, with respect to accounts receivable, exist to the extent of amounts presented in the financial statements. Generally, the Company does not require collateral or other security to support customer receivables. The Company performs periodic credit evaluations of its customers and maintains an allowance for potential credit losses based on historical experience and other information available to management. Losses to date have not been material. The Company’s ten largest customers represented 46% and 55% of total accounts receivable at May 3, 2015 and April 27, 2014, respectively. No customers accounted for over 10% of total accounts receivable as of May 3, 2015. Two customers accounted for 12% and 11%, respectively, of total accounts receivable as of April 27, 2014.
	Sales to the Company’s ten largest customers represented 55%, 58% and 54% of total revenues during fiscal 2015, 2014 and 2013, respectively. One customer, Cisco Systems, represented 14%, 17% and 17% of total revenues during fiscal 2015, 2014 and 2013, respectively.
	The Company relies on single and limited suppliers for a number of key components. The Company relies primarily on a limited number of significant independent contract manufacturers for the production of certain key components and subassemblies, including lasers, modulators, and printed circuit boards.
Foreign Currency Translation	Foreign Currency Translation
	The functional currency of the Company's foreign subsidiaries is the local currency. Assets and liabilities denominated in foreign currencies are translated using the exchange rate on the balance sheet date. Revenues and expenses are translated using average exchange rates prevailing during the year. Any translation adjustments resulting from this process are shown separately as a component of accumulated other comprehensive income (loss). Foreign currency transaction gains and losses are included in the determination of net income (loss).
Research and Development	Research and Development
	Research and development expenditures are charged to operations as incurred.
Shipping and Handling Costs	Shipping and Handling Costs
	The Company records costs related to shipping and handling in cost of sales for all periods presented.
Cash and Cash Equivalents	Cash and Cash Equivalents
	Finisar’s cash equivalents consist of money market funds and highly liquid short-term investments with qualified financial institutions. Finisar considers all highly liquid investments with an original maturity from the date of purchase of three months or less to be cash equivalents.
Minority Investments	Minority Investments
	The Company uses the cost method of accounting for investments in companies that do not have a readily determinable fair value in which it holds an interest of less than 20% and over which it does not have the ability to exercise significant influence. For entities in which the Company holds an interest of greater than 20% or in which the Company does have the ability to exercise significant influence, the Company uses the equity method. Under the equity method of accounting, investments are stated at initial cost and are adjusted for subsequent additional investments and the Company's proportionate share of earnings or losses and distributions. In determining if and when a decline in the market value of these investments below their carrying value is other-than-temporary, the Company evaluates the market conditions, offering prices, trends of earnings and cash flows, price multiples, prospects for liquidity and other key measures of performance. The Company’s policy is to recognize an impairment in the value of its minority equity investments when clear evidence of an impairment exists. Factors considered in this assessment include (a) the completion of a new equity financing that may indicate a new value for the investment, (b) the failure to complete a new equity financing arrangement after seeking to raise additional funds or (c) the commencement of proceedings under which the assets of the business may be placed in receivership or liquidated to satisfy the claims of debt and equity stakeholders. The Company’s minority investments in private companies are generally made in exchange for preferred stock with a liquidation preference that is intended to help protect the underlying value of its investment.
Fair Value Accounting	Fair Value Accounting
	The FASB authoritative guidance regarding fair valuation defines fair value and establishes a framework for measuring fair value and expands the related disclosure requirements. The guidance requires or permits fair value measurements with certain exclusions. It provides that a fair value measurement assumes that the transaction to sell an asset or transfer a liability occurs in the principal market for the asset or liability or, in the absence of a principal market, the most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The guidance establishes a valuation hierarchy for disclosure of the inputs to valuation used to measure fair value. Valuation techniques used to measure fair value under this guidance must maximize the use of observable inputs and minimize the use of unobservable inputs. It describes a fair value hierarchy based on three levels of inputs, of which the first two are considered observable and the last unobservable, that may be used to measure fair value which are the following:
	Level 1 inputs are unadjusted quoted prices in active markets for identical assets or liabilities;
	Level 2 inputs are quoted prices for similar assets and liabilities in active markets or inputs that are observable for the asset or liability, either directly or indirectly through market corroboration, for substantially the full term of the financial instrument; and
	Level 3 inputs are unobservable inputs based on the Company's own assumptions used to measure assets and liabilities at fair value. A financial asset or liability’s classification within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement.
	The Company’s Level 1 assets include instruments valued based on quoted market prices in active markets, which generally include money market funds. The Company classifies items in Level 2 if the investments are valued using observable inputs to quoted market prices, benchmark yields, reported trades, broker/dealer quotes or alternative pricing sources with reasonable levels of price transparency. These investments include commercial papers and certificates of deposit. See Note 11 for additional details regarding the fair value of the Company’s investments.
Allowance for Doubtful Accounts	Allowance for Doubtful Accounts
	The Company evaluates the collectability of its accounts receivable based on a combination of factors. In circumstances where, subsequent to delivery, the Company becomes aware of a customer’s potential inability to meet its obligations, it records a specific allowance for the doubtful account to reduce the net recognized receivable to the amount the Company reasonably believes will be collected. For all other customers, the Company recognizes an allowance for doubtful accounts based on the length of time the receivables are past due and historical actual bad debt history. A material adverse change in a major customer’s ability to meet its financial obligations to the Company could result in a material reduction in the estimated amount of accounts receivable that can ultimately be collected and an increase in the Company’s general and administrative expenses for the shortfall. Accounts receivable are charged against the allowance for doubtful accounts when identified as fully uncollectable.
Inventories	Inventories
	Inventories are stated at the lower of cost (determined on a first-in, first-out basis) or market.
	The Company permanently writes down to its estimated net realizable value the cost of inventory that the Company specifically identifies and considers obsolete or excessive to fulfill future sales estimates. The Company defines obsolete inventory as inventory that will no longer be used in the manufacturing process. Excess inventory is generally defined as inventory in excess of projected usage and is determined using management’s best estimate of future demand, based upon information then available to the Company. The Company also considers: (1) parts and subassemblies that can be used in alternative finished products, (2) parts and subassemblies that are unlikely to be engineered out of the Company’s products, and (3) known design changes which would reduce the Company’s ability to use the inventory as planned. Inventory on hand that is in excess of future demand is written down to its estimated net realizable value. Obligations to purchase inventory acquired by subcontractors based on forecasts provided by the Company are recognized at the time such obligations arise.
Property, Equipment and Improvements	Property, Equipment and Improvements
	Property, equipment and improvements are stated at cost, net of accumulated depreciation and amortization. Property, equipment and improvements are depreciated on a straight-line basis over the estimated useful lives of the assets, generally three years to seven years, except for buildings which are depreciated over 25 years. Land is carried at acquisition cost and not depreciated. Leased land is depreciated over the life of the lease.
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets
	Goodwill, purchased technology and other intangible assets resulting from acquisitions are accounted for under the acquisition method. Intangible assets with finite lives are amortized over their estimated useful lives. Amortization of purchased technology and other intangibles has been recorded on a straight-line basis over periods ranging from three to 15 years. Goodwill is assessed for impairment annually or more frequently when an event occurs or circumstances change between annual impairment tests that would more likely than not reduce the fair value of the reporting unit holding the goodwill below its carrying value.
Accounting for Impairment of Long-Lived Assets	Accounting for the Impairment of Long-Lived Assets
	The Company periodically evaluates whether changes have occurred to long-lived assets that would require revision of the remaining estimated useful life of the property, improvements and finite-lived intangible assets or render them not recoverable. If such circumstances arise, the Company uses an estimate of the undiscounted value of expected future operating cash flows to determine whether the long-lived assets are impaired. If the aggregate undiscounted cash flows are less than the carrying amount of the assets, the resulting impairment charge to be recorded is calculated based on the excess of the carrying value of the assets over the fair value of such assets, with the fair value determined based on an estimate of discounted future cash flows.
Restructuring Costs	Restructuring Costs
	The Company recognizes liability for exit and disposal activities when the liability is incurred. Facilities consolidation charges are calculated using estimates and are based upon the remaining future lease commitments for vacated facilities from the date of facility consolidation, net of estimated future sublease income. The estimated costs of vacating these leased facilities are based on market information and trend analysis, including information obtained from third party real estate sources.
Stock-Based Compensation Expense	Stock-Based Compensation Expense
	The Company measures and recognizes compensation expense for all stock-based payment awards made to employees and directors including employee stock options, restricted stock units and employee stock purchases under the Company’s Employee Stock Purchase Plan based on estimated fair values. The Company uses the grant-date fair value of its common stock to determine the fair value of restricted stock units. The Company uses the Black-Scholes option pricing model to determine the fair value of stock options and employee stock purchases. The fair value of the portion of the awards that is ultimately expected to vest is recognized as expense in the consolidated statements of operations under the single-option approach on a straight-line basis over the requisite service periods
Income Taxes	Income Taxes
	The Company uses the liability method to account for income taxes. Under this method, income tax expense is recognized for the amount of taxes payable or refundable for the current year. Deferred tax assets and liabilities are recognized using enacted tax rates for the effect of temporary differences between the book and tax basis of recorded assets and liabilities and their reported amounts, along with net operating loss carryforwards and credit carryforwards. This method also requires that deferred tax assets be reduced by a valuation allowance if it is more likely than not that a portion of the deferred tax asset will not be realized.
	The Company provides for income taxes based upon the geographic composition of worldwide earnings and tax regulations governing each region. The calculation of tax liabilities involves significant judgment in estimating the impact of uncertainties in the application of complex tax laws. Also, the Company’s current effective tax rate assumes that United States income taxes are not provided for the undistributed earnings of non-United States subsidiaries. The Company intends to indefinitely reinvest the earnings of all foreign corporate subsidiaries for past and subsequent accumulated earnings.
Recent and Pending Adoption of New Accounting Standards	Recent and Pending Adoption of New Accounting Standards
	In May 2014, the FASB, jointly with the International Accounting Standards Board, issued a comprehensive new standard on revenue recognition from contracts with customers. The standard's core principle is that a reporting entity will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In applying this new guidance to contracts within its scope, an entity will: (1) identify the contract(s) with a customer, (2) identify the performance obligation in the contract, (3) determine the transaction price, (4) allocate the transaction price to the performance obligations in the contract, and (5) recognize revenue when (or as) the entity satisfies a performance obligation. Additionally, this new guidance would require significantly expanded disclosures about revenue recognition. Provisions of this new standard are effective for annual reporting periods (including interim reporting periods within those annual periods) beginning after December 15, 2016. In April 2015, the FASB proposed a deferral of this standard's effective date by one year. The proposed deferral allows early adoption at the original effective date. Entities have the option of using either a full retrospective or a modified retrospective approach to adopt this new guidance. The Company is currently evaluating the potential effect on its consolidated financial position, results of operations and cash flows from adoption of this standard.
	From time to time, new accounting pronouncements are issued by the FASB or other standards setting bodies that are adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes the impact of recently issued standards that are not yet effective will not have a material impact on its consolidated financial position, results of operations and cash flows upon adoption.
Net Income (Loss) Per Share	Basic net income (loss) per share has been computed using the weighted-average number of shares of common stock outstanding during the period. Diluted net income (loss) per share has been computed using the weighted-average number of shares of common stock and dilutive potential common shares from stock options and restricted stock units (under the treasury stock method), 5.0% Convertible Senior Notes due 2029 (on an as-if-converted basis), and 0.50% Convertible Senior Notes due 2033 (under the treasury stock method) outstanding during the period.
Warranty	The Company generally offers a one-year limited warranty for its products. The specific terms and conditions of these warranties vary depending upon the product sold. The Company estimates the costs that may be incurred under its basic limited warranty and records a liability for the amount of such costs at the time revenue is recognized. Factors that affect the Company’s warranty liability include the historical and anticipated rates of warranty claims and cost to repair. The Company periodically assesses the adequacy of its recorded warranty liabilities and adjusts the amounts as necessary.

Net_Income_Loss_Per_Share_Tabl

Net Income (Loss) Per Share (Tables)	12 Months Ended
	3-May-15
Earnings Per Share [Abstract]
Schedule of Calculation of Basic and Diluted Net Income (Loss) Per Share	The following table presents the calculation of basic and diluted net income (loss) per share:
		Fiscal Years Ended
	(in thousands, except per share amounts)	May 3, 2015			April 27, 2014			April 28, 2013
	Numerator:
	Net income (loss) attributable to Finisar Corporation	$	11,887		$	111,787		$	(5,454	)
	Numerator for basic income (loss) per share	$	11,887		$	111,787		$	(5,454	)
	Effect of dilutive securities:
	Interest expense on 5.0% Convertible Senior Notes due 2029	—			2,157			—
	Numerator for diluted income (loss) per share	$	11,887		$	113,944		$	(5,454	)
	Denominator:
	Denominator for basic income (loss) per share - weighted average shares	101,408			95,979			92,860
	Effect of dilutive securities:
	Stock options and restricted stock units	3,562			4,385			—
	5.0% Convertible Senior Notes due 2029	—			3,748			—
	Dilutive potential common shares	3,562			8,133			—
	Denominator for diluted income (loss) per share	104,970			104,112			92,860
	Net income (loss) per share attributable to Finisar Corporation common stockholders:
	Basic	$	0.12		$	1.16		$	(0.06	)
	Diluted	$	0.11		$	1.09		$	(0.06	)
Schedule of Antidilutive Securities Excluded from Computation of Net Income (Loss) Per Share	The following table presents common shares related to potentially dilutive securities excluded from the calculation of diluted net income (loss) per share as their effect would have been anti-dilutive:
		Fiscal Years Ended
	(in thousands)	May 3, 2015		April 27, 2014			April 28, 2013
	Stock options and restricted stock units	880		1,057			4,599
	Conversion of 5.0% Convertible Senior Notes due 2029	—		—			3,748
	Conversion of 0.50% Convertible Senior Notes due 2033 (1)	—		—			n/a
		880		1,057			8,347
	(1) 0.50% Convertible Senior Notes due 2033 were excluded from the calculation of diluted earnings per share under the treasury stock method since the conversion price exceeded the average market price for the Company's common stock.

Intangible_Assets_Including_Go1

Intangible Assets Including Goodwill (Tables)	12 Months Ended
	3-May-15
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Finite-Lived Intangible Assets	The following tables reflect intangible assets as of May 3, 2015 and April 27, 2014:
		May 3, 2015
	(in thousands)	Gross Carrying Amount			Accumulated			Net Carrying Amount
					Amortization
	Purchased technology	$	103,859		$	(90,746	)	$	13,113
	Purchased trade name	1,172			(1,172		)	—
	Purchased customer relationships	21,344			(13,648		)	7,696
	Purchased internal use software and backlog	2,816			(1,991		)	825
	Purchased patents	2,620			(966		)	1,654
	Total intangible assets subject to amortization	131,811			(108,523		)	23,288
	In-process research and development	3,900			—			3,900
	Total	$	135,711		$	(108,523	)	$	27,188
		April 27, 2014
	(in thousands)	Gross Carrying Amount			Accumulated			Net Carrying Amount
					Amortization
	Purchased technology	$	102,124		$	(85,007	)	$	17,117
	Purchased trade name	1,172			(1,172		)	—
	Purchased customer relationships	21,344			(11,344		)	10,000
	Purchased internal use software and backlog	2,816			(1,666		)	1,150
	Purchased patents	2,620			(647		)	1,973
	Total intangible assets subject to amortization	130,076			(99,836		)	30,240
	In-process research and development	3,900			—			3,900
	Total	$	133,976		$	(99,836	)	$	34,140
Schedule of Indefinite-Lived Intangible Assets	The following tables reflect intangible assets as of May 3, 2015 and April 27, 2014:
		May 3, 2015
	(in thousands)	Gross Carrying Amount			Accumulated			Net Carrying Amount
					Amortization
	Purchased technology	$	103,859		$	(90,746	)	$	13,113
	Purchased trade name	1,172			(1,172		)	—
	Purchased customer relationships	21,344			(13,648		)	7,696
	Purchased internal use software and backlog	2,816			(1,991		)	825
	Purchased patents	2,620			(966		)	1,654
	Total intangible assets subject to amortization	131,811			(108,523		)	23,288
	In-process research and development	3,900			—			3,900
	Total	$	135,711		$	(108,523	)	$	27,188
		April 27, 2014
	(in thousands)	Gross Carrying Amount			Accumulated			Net Carrying Amount
					Amortization
	Purchased technology	$	102,124		$	(85,007	)	$	17,117
	Purchased trade name	1,172			(1,172		)	—
	Purchased customer relationships	21,344			(11,344		)	10,000
	Purchased internal use software and backlog	2,816			(1,666		)	1,150
	Purchased patents	2,620			(647		)	1,973
	Total intangible assets subject to amortization	130,076			(99,836		)	30,240
	In-process research and development	3,900			—			3,900
	Total	$	133,976		$	(99,836	)	$	34,140
Schedule of Expected Future Amortization Expense	Estimated amortization expense for each of the next five fiscal years and thereafter as of May 3, 2015 is as follows:
	Year	Amount (in thousands)
	2016	$	8,413
	2017	6,328
	2018	4,218
	2019	2,729
	2020	1,251
	2021 and beyond	349
	Total	$	23,288
Schedule of Goodwill	The following table reflects the changes to the carrying amount of goodwill (in thousands):
	Balance at April 28, 2013	$	90,986
	Addition related to an acquisition	15,252
	Goodwill allocated to asset disposal groups	(124		)
	Balance at April 27, 2014	106,114
	Addition related to an acquisition	622
	Balance at May 3, 2015	$	106,736

Investments_Tables

Investments (Tables)	12 Months Ended
	3-May-15
Investments, Debt and Equity Securities [Abstract]
Schedule of Held-to-Maturity Securities	The Company's investments in fixed income securities as of May 3, 2015 and April 27, 2014 were as follows:
		May 3, 2015								27-Apr-14
				Gross Unrealized								Gross Unrealized
	(in thousands)	Amortized Cost		Gains		Losses		Fair Value		Amortized Cost		Gains		Losses		Fair Value
	Commercial paper	$	—	$	—	$	—	$	—	$	89,922	$	—	$	—	$	89,922
	Certificates of deposit	292,748		—		—		292,748		120,000		—		—		120,000
	Total	$	292,748	$	—	$	—	$	292,748	$	209,922	$	—	$	—	$	209,922
	Reported as:
	Short-term investments	$	292,748	$	—	$	—	$	292,748	$	209,922	$	—	$	—	$	209,922

Inventories_Tables

Inventories (Tables)	12 Months Ended
	3-May-15
Inventory Disclosure [Abstract]
Schedule of Inventory
	Inventories consist of the following (in thousands):	As of
		May 3, 2015		April 27, 2014
	Raw materials	$	57,757	$	52,594
	Work-in-process	146,773		126,181
	Finished goods	79,140		80,984
	Total inventories	$	283,670	$	259,759
	Including: inventory consigned to others	$	34,240	$	31,998

Property_Equipment_and_Improve1

Property, Equipment and Improvements (Tables)	12 Months Ended
	3-May-15
Property, Plant and Equipment [Abstract]
Schedule of Property, Equipment and Improvements
	Property, equipment and improvements consist of the following (in thousands):	As of
		May 3, 2015			April 27, 2014
	Land and buildings	$	68,286		$	49,995
	Computer equipment	62,857			55,611
	Office equipment, furniture and fixtures	5,251			5,213
	Machinery and equipment	493,224			435,262
	Leasehold property and improvements	42,099			37,353
	Total	671,717			583,434
	Accumulated depreciation and amortization	(355,940		)	(310,106		)
	Property, equipment and improvements (net)	$	315,777		$	273,328

Other_Accrued_Liabilities_Tabl

Other Accrued Liabilities (Tables)	12 Months Ended
	3-May-15
Other Liabilities Disclosure [Abstract]
Schedule of Other Current Liabilities
	Other current liabilities consist of the following (in thousands):	As of
		May 3, 2015		April 27, 2014
	Warranty accrual (Note 18)	$	6,451	$	5,744
	Other liabilities	32,788		26,032
	Total	$	39,239	$	31,776

Debt_Tables

Debt (Tables)	12 Months Ended
	3-May-15
Debt Disclosure [Abstract]
Schedule of Convertible Debt	The Company’s convertible debt as of May 3, 2015 and April 27, 2014 is summarized as follows (in thousands):
			Carrying		Interest	Due in
	Description		amount		rate	fiscal year
	As of May 3, 2015
	Convertible Senior Notes due December 2033		221,406		0.50%	2034
	Total		$	221,406
	As of April 27, 2014
	Convertible Senior Notes due October 2029		$	40,015	5.00%	2030
	Convertible Senior Notes due December 2033		$	212,253	0.50%	2034
	Total		$	252,268
Convertible Debt	The 2033 Notes consisted of the following:
		As of
	(in thousands)	May 3, 2015
	Liability component:
	Principal	$	258,750
	Unamortized debt discount	(37,344		)
	Net carrying amount of the liability component	$	221,406
	Carrying amount of the equity component	$	49,648
Interest Expense	The following table sets forth interest expense information for the year ended May 3, 2015 related to the 2033 Notes:
	(in thousands, except percentages)
	Contractual interest expense	$	1,294
	Amortization of the debt discount	9,153
	Amortization of issuance costs	616
	Total interest cost	$	11,063
	Effective interest rate on the liability component	4.87		%

Commitments_Tables

Commitments (Tables)	12 Months Ended
	3-May-15
Commitments and Contingencies Disclosure [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases	The Company’s future commitments at May 3, 2015 included minimum payments under non-cancelable operating lease agreements, including operating lease obligations that have been accrued as restructuring charges, as follows (in thousands):
				Payments Due by Period
		Total		Less Than 1 Year		1-3 Years		4-5 Years		After 5 Years
	Operating leases	$	51,695	$	10,573	$	19,426	$	14,390	$	7,306

Fair_Value_of_Financial_Instru1

Fair Value of Financial Instruments (Tables)	12 Months Ended
	3-May-15
Fair Value Disclosures [Abstract]
Schedule of Fair Value Assets Measured on a Recurring Basis	The Company's financial instruments measured at fair value on a recurring basis as of May 3, 2015 and April 27, 2014 were as follows:
		May 3, 2015										April 27, 2014
		Carrying		Fair Value								Carrying		Fair Value
	(in thousands)	Amount		Level 1		Level 2		Level 3		Total		Amount		Level 1		Level 2		Level 3		Total
	Money market funds	$	196	$	196	$	—	$	—	$	196	$	30,169	$	30,169	$	—	$	—	$	30,169
	Commercial paper	—		—		—		—		—		89,922		—		89,922		—		89,922
	Certificates of deposit	292,748		—		292,748		—		292,748		120,000		—		120,000		—		120,000
	Total	$	292,944	$	196	$	292,748	$	—	$	292,944	$	240,091	$	30,169	$	209,922	$	—	$	240,091
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]	The Company's financial instruments not measured at fair value on a recurring basis as of May 3, 2015 and April 27, 2014 were as follows:
		May 3, 2015										April 27, 2014
		Carrying		Fair Value								Carrying		Fair Value
	(in thousands)	Amount		Level 1		Level 2		Level 3		Total		Amount		Level 1		Level 2		Level 3		Total
	2029 Notes	$	—	$	—	$	—	$	—	$	—	$	40,015	$	104,105	$	—	$	—	$	104,105
	2033 Notes	221,406		264,364		—		—		264,364		212,253		305,325		—		—		305,307
	Total	$	221,406	$	264,364	$	—	$	—	$	264,364	$	252,268	$	409,430	$	—	$	—	$	409,412

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	12 Months Ended
	3-May-15
Equity [Abstract]
Schedule of Common Stock Subject to Future Issuance	Common stock subject to future issuance as of May 3, 2015 is as follows:
	Exercise of outstanding stock options	2,283,162
	Vesting of restricted stock awards	6,611,614
	Available for grant under employee stock incentive plan	13,023,873
	Available for grant under employee stock purchase plan	4,249,965
	Total	26,168,614
Schedule of Stock Options	Stock Options
		Number of Shares			Weighted-Average Exercise Price
	Stock options outstanding as of April 27, 2014	2,621,844			$	14.28
	Stock options exercised	(299,517	)		$	10.27
	Stock options canceled	(39,165	)		$	23.61
	Stock options outstanding as of May 3, 2015	2,283,162			$	14.64
Schedule of Restricted Stock Units	Restricted Stock Units
		Number of Shares			Weighted-Average Grant-Date Fair Value
	RSUs unvested as of April 27, 2014	6,516,317			$	15.44
	RSUs granted	2,831,517			$	19.55
	RSUs vested	(2,350,245	)		$	15.42
	RSUs forfeited	(385,975	)		$	17.04
	RSUs unvested as of May 3, 2015	6,611,614			$	17.12
Schedule of Share-Based Compensation Expense	The following table sets forth the detailed allocation of the share-based compensation expense for the fiscal years ended May 3, 2015, April 27, 2014 and April 28, 2013 which was reflected in the Company’s operating results (in thousands):
		Fiscal Years Ended
	Share-based compensation expense by caption:	May 3, 2015				April 27, 2014			April 28, 2013
	Cost of revenues	$	9,908			$	8,261		$	6,915
	Research and development	17,764				14,660			10,970
	Sales and marketing	6,251				5,083			3,743
	General and administrative	10,677				9,962			10,333
	Total	$	44,600			$	37,966		$	31,961
		Fiscal Years Ended
	Share-based compensation expense by type of award:	May 3, 2015				April 27, 2014			April 28, 2013
	Stock options	$	—			$	693		$	1,892
	RSUs	41,729				34,506			26,794
	Employee stock purchase rights under ESPP	2,871				2,767			3,275
	Total	$	44,600			$	37,966		$	31,961
Schedule of Employee Stock Purchase Plan Valuation Assumptions	The fair value of employee stock purchase rights granted under the ESPP in fiscal 2015, 2014 and 2013 was estimated at the date of grant using the Black-Scholes option-pricing model with the following weighted-average assumptions:
			Fiscal Years Ended
			May 3, 2015			April 27, 2014		April 28, 2013
	Expected term (in years)		0.75			0.75		0.75
	Volatility		34% - 53%			40% - 47%		50% - 53%
	Risk-free interest rate		0.07 - 0.21%			0.01 - 0.13%		0.10 - 0.15%
	Dividend yield		—	%		—	%	—	%

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	3-May-15
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit)	The components of income tax expense (benefit) consist of the following (in thousands):
		Fiscal Years Ended
		May 3, 2015				April 27, 2014				April 28, 2013
	Current:
	Federal	$	—			$	(385	)		$	—
	State	209				523				(45		)
	Foreign	8,814				5,691				3,896
		9,023				5,829				3,851
	Deferred:
	Federal	(607		)		—				—
	State	(14		)		—				—
	Foreign	393				(2,945		)		(3,624		)
		(228		)		(2,945		)		(3,624		)
	Provision for income taxes	$	8,795			$	2,884			$	227
	Income (loss) before income taxes and non-controlling interest consists of the following (in thousands):
		Fiscal Years Ended
		May 3, 2015				April 27, 2014				April 28, 2013
	U.S.	$	(29,300	)		$	46,314			$	(21,863	)
	Foreign	49,982				68,107				14,025
		$	20,682			$	114,421			$	(7,838	)
Schedule of Effective Income Tax Rate Reconciliation	A reconciliation of the income tax provision at the federal statutory rate and the effective rate is as follows:
		Fiscal Years Ended
		May 3, 2015			April 27, 2014			April 28, 2013
	Expected income tax provision (benefit) at U.S. federal statutory rate	35	%		35	%		35	%
	Foreign rate differential	(46.9	)		(18.3	)		38.3
	Share-based compensation expense	29.6			2.5			(45.2	)
	Non-deductible transaction costs	0.5			0.4			(5.8	)
	Non-recurring acquisition-related gain	—			—			31.1
	Valuation allowance	49.1			(21.4	)		(101.0	)
	Intangibles impairment	—			—			36.8
	Research and development credits	(15.0	)		(1.8	)		18.7
	Non-deductible acquisition-related charge	—			—			(6.2	)
	Other	(9.8	)		6.1			(4.6	)
		42.5	%		2.5	%		(2.9	)%
Schedule of Deferred Tax Assets and Liabilities	The components of deferred taxes consist of the following (in thousands):
		Fiscal Years Ended
		May 3, 2015				April 27, 2014				April 28, 2013
	Deferred tax assets:
	Inventory adjustments	$	10,024			$	8,905			$	9,170
	Accruals and reserves	13,081				18,673				14,194
	Tax credits	27,836				24,259				21,869
	Net operating loss carryforwards	101,850				95,952				155,281
	Gain/loss on investments under equity or cost method	8,367				8,843				8,931
	Depreciation and amortization	4,509				2,817				1,915
	Purchase accounting for intangible assets	4,438				5,651				190
	Capital loss carryforward	172				229				563
	Acquired intangibles	8,208				10,142				18,356
	Stock compensation	9,302				8,372				7,917
	Total deferred tax assets	187,787				183,843				238,386
	Valuation allowance	(161,358		)		(153,657		)		(227,889		)
	Net deferred tax assets	26,429				30,186				10,497
	Deferred tax liabilities:
	Acquired intangibles	(5,597		)		(7,252		)		(5,128		)
	Debt discount	(13,862		)		(16,873		)		(1,592		)
	Inventory reserve	(513		)		(457		)		(1,791		)
	Depreciation and amortization	(7,068		)		(5,762		)		(774		)
	Total deferred tax liabilities	(27,040		)		(30,344		)		(9,285		)
	Total net deferred tax assets (liabilities)	$	(611	)		$	(158	)		$	1,212
Summary of Movement in Gross Unrecognized Tax Benefits	A reconciliation of the beginning and ending amount of the gross unrecognized tax benefits is as follows (in thousands):
		Fiscal Years Ended
		May 3, 2015				April 27, 2014				April 28, 2013
	Beginning balance	$	13,432			$	15,632			$	14,634
	Additions for tax positions related to current year	975				712				241
	Additions for tax positions related to prior years	246				—				757
	Reductions for tax positions related to prior years (lapse of statute of limitations)	—				(2,912		)		—
	Ending balance	$	14,653			$	13,432			$	15,632

Segments_and_Geography_Informa1

Segments and Geography Information (Tables)	12 Months Ended
	3-May-15
Segment Reporting [Abstract]
Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Table Text Block]	The following is a summary of revenues from sales to unaffiliated customers within geographic areas based on the location of the entity purchasing the Company’s products:
		Fiscal Years Ended
	(in thousands)	May 3, 2015		April 27, 2014		April 28, 2013
	United States	$	425,066	$	339,423	$	269,071
	Malaysia	148,258		185,197		183,299
	China	242,916		229,231		171,016
	Rest of the world	434,704		402,982		310,949
	Totals	$	1,250,944	$	1,156,833	$	934,335
	Revenues generated in the United States are all from sales to customers located in the United States.
	The following is a summary of long-lived assets within geographic areas based on the location of the assets:
		As of
	(in thousands)	May 3, 2015		April 27, 2014
	United States	$	122,118	$	110,573
	Malaysia	54,480		56,007
	China	175,580		127,966
	Rest of the world	28,704		32,312
		$	380,882	$	326,858

Restructuring_Charges_Tables

Restructuring Charges (Tables)	12 Months Ended
	3-May-15
Restructuring and Related Activities [Abstract]
Schedule of Restructuring Reserve	The following table summarizes the activities of the restructuring accrual during fiscal 2015 (in thousands):
	Balance as of April 27, 2014	$	2,911
	Cash payments, net of sublease income	(351		)
	Balance as of May 3, 2015	$	2,560

Warranty_Tables

Warranty (Tables)	12 Months Ended
	3-May-15
Product Warranties Disclosures [Abstract]
Schedule of Product Warranty Liability	Changes in the Company’s warranty liability during the following periods were as follows:
		As of
	(in thousands)	May 3, 2015			April 27, 2014
	Beginning balance	$	5,744		$	4,155
	Additions during the period based on product sold	6,171			5,653
	Additions during the period due to acquisitions	—			515
	Change in estimates	(1,388		)	(2,022		)
	Settlements and expirations	(4,076		)	(2,557		)
	Ending balance	$	6,451		$	5,744

Financial_Information_by_Quart1

Financial Information by Quarter (Unaudited) (Tables)	12 Months Ended
	3-May-15
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information
		Three Months Ended
		3-May-15		January 25, 2015 (1)		October 26, 2014 (2)			27-Jul-14		April 27, 2014 (3)		26-Jan-14		27-Oct-13		July 28, 2013 (4)
		(In thousands, except per share data)
	Revenues	$	320,042	$	306,283	$	296,981		$	327,638	$	306,025	$	294,018	$	290,722	$	266,068
	Gross profit	$	89,217	$	77,953	$	84,921		$	98,819	$	96,564	$	105,689	$	103,373	$	91,373
	Income (loss) from operations	$	10,284	$	3,401	$	(7,259	)	$	20,368	$	21,107	$	33,096	$	30,109	$	27,103
	Income (loss) before non-controlling interest	$	7,327	$	1,678	$	(11,361	)	$	14,243	$	28,683	$	27,068	$	29,951	$	25,835
	Net income (loss) attributable to Finisar Corporation	$	7,327	$	1,678	$	(11,361	)	$	14,243	$	28,750	$	27,061	$	29,965	$	26,011
	Net income (loss) per share attributable to Finisar Corporation common stockholders:
	Basic	$	0.07	$	0.02	$	(0.11	)	$	0.14	$	0.3	$	0.28	$	0.31	$	0.27
	Diluted	$	0.07	$	0.02	$	(0.11	)	$	0.14	$	0.28	$	0.26	$	0.29	$	0.26
	Shares used in computing net income (loss) per share:
	Basic	104,005		103,563		99,621			98,241		96,965		96,394		95,941		94,609
	Diluted	107,535		105,990		99,621			106,036		105,418		104,361		103,696		101,125
	(1) Net income in the third quarter of fiscal 2015 includes a $5.8 million impairment charge for long-lived assets.
	(2) Net loss in the second quarter of fiscal 2015 includes an $11.0 million charge related to the settlement of patent litigation.
	(3) Net income in the fourth quarter of fiscal 2014 includes an $8.2 million gain on divestiture of majority-owned subsidiary, Finisar Korea.
	(4) Net income in the first quarter of fiscal 2014 includes a $6.5 million gain related to the settlement of stock option litigation.

Description_of_Business_and_Ba1

Description of Business and Basis of Presentation (Details)	12 Months Ended
	3-May-15	Apr. 27, 2014	1-May-16
Description of Business and Basis of Presentation [Line Items]
Fiscal period duration	371 days	365 days
Minimum
Description of Business and Basis of Presentation [Line Items]
Digital signal speed	0.125
Digital signal distance	10
Number of high-speed optical channels	50
Maximum
Description of Business and Basis of Presentation [Line Items]
Digital signal speed	12.5
Digital signal distance	2,000
Number of high-speed optical channels	100
Forecast
Description of Business and Basis of Presentation [Line Items]
Fiscal period duration			365 days

Summary_of_Significant_Account2

Summary of Significant Accounting Policies - Segment Reporting and Concentration Risk (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	3-May-15	Apr. 27, 2014	Apr. 28, 2013
Accounting Policies [Abstract]
Number of reportable segments	1
Concentration Risk [Line Items]
Net assets located overseas	470.8
Customer Concentration Risk | Accounts Receivable | 10 Largest Customers
Concentration Risk [Line Items]
Concentration risk (percentage)	46.00%	55.00%
Customer Concentration Risk | Accounts Receivable | Customer A
Concentration Risk [Line Items]
Concentration risk (percentage)		12.00%
Customer Concentration Risk | Accounts Receivable | Customer B
Concentration Risk [Line Items]
Concentration risk (percentage)		11.00%
Customer Concentration Risk | Revenues | 10 Largest Customers
Concentration Risk [Line Items]
Concentration risk (percentage)	55.00%	58.00%	54.00%
Customer Concentration Risk | Revenues | Cisco Systems
Concentration Risk [Line Items]
Concentration risk (percentage)	14.00%	17.00%	17.00%

Summary_of_Significant_Account3

Summary of Significant Accounting Policies - Foreign Currency Translation and PPE (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	3-May-15	Apr. 27, 2014	Apr. 28, 2013
Accounting Policies [Abstract]
Gains (losses) on foreign currency transactions	($479)	($2,500)	($861)
Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life (property, equipment and improvements)	3 years
Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life (property, equipment and improvements)	7 years
Land, Buildings and Improvements
Property, Plant and Equipment [Line Items]
Estimated useful life (property, equipment and improvements)	25 years

Summary_of_Significant_Account4

Summary of Significant Accounting Policies - Goodwill and Intangible Assets (Details)	12 Months Ended
	3-May-15
Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated useful life (intangible assets)	3 years
Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated useful life (intangible assets)	15 years

Net_Income_Loss_Per_Share_Sche

Net Income (Loss) Per Share - Schedule of Calculation of Basic and Diluted Net Income (Loss) Per Share (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	3-May-15	Jan. 25, 2015	Oct. 26, 2014	Jul. 27, 2014	Apr. 27, 2014	Jan. 26, 2014	Oct. 27, 2013	Jul. 28, 2013	3-May-15	Apr. 27, 2014	Apr. 28, 2013	Dec. 31, 2013
Numerator:
Numerator for basic income (loss) per share	$7,327	$1,678	($11,361)	$14,243	$28,750	$27,061	$29,965	$26,011	$11,887	$111,787	($5,454)
Interest expense on 5.0% Convertible Senior Notes due 2029									0	2,157	0
Numerator for diluted income (loss) per share									$11,887	$113,944	($5,454)
Denominator:
Denominator for basic income (loss) per share - weighted average shares	104,005	103,563	99,621	98,241	96,965	96,394	95,941	94,609	101,408	95,979	92,860
Effect of dilutive securities:
Stock options and restricted stock units									3,562	4,385	0
5.0% Convertible Senior Notes due 2029									0	3,748	0
Dilutive potential common shares									3,562	8,133	0
Denominator for diluted income (loss) per share	107,535	105,990	99,621	106,036	105,418	104,361	103,696	101,125	104,970	104,112	92,860
Net income (loss) per share attributable to Finisar Corporation common stockholders:
Basic (in usd)	$0.07	$0.02	($0.11)	$0.14	$0.30	$0.28	$0.31	$0.27	$0.12	$1.16	($0.06)
Diluted (in usd)	$0.07	$0.02	($0.11)	$0.14	$0.28	$0.26	$0.29	$0.26	$0.11	$1.09	($0.06)
5.0% Convertible Senior Notes Due 2029
Debt Instrument [Line Items]
Interest rate	5.00%				5.00%				5.00%	5.00%
0.5% Convertible Senior Notes Due 2033
Debt Instrument [Line Items]
Interest rate	0.50%				0.50%				0.50%	0.50%		0.50%

Net_Income_Loss_Per_Share_Sche1

Net Income (Loss) Per Share - Schedule of Antidilutive Securities Excluded from Computation of Net Income (Loss) Per Share (Details)	12 Months Ended
In Thousands, unless otherwise specified	3-May-15		Apr. 27, 2014		Apr. 28, 2013	Dec. 31, 2013
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive securities excluded from computation of earnings per share	880		1,057		8,347
5.0% Convertible Senior Notes Due 2029
Antidilutive Securities Excluded from Computation of Earnings Per Share
Interest rate	5.00%		5.00%
0.5% Convertible Senior Notes Due 2033
Antidilutive Securities Excluded from Computation of Earnings Per Share
Interest rate	0.50%		0.50%			0.50%
Stock Options and Restricted Stock Units
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive securities excluded from computation of earnings per share	880		1,057		4,599
Convertible Debt | 5.0% Convertible Senior Notes Due 2029
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive securities excluded from computation of earnings per share	0		0		3,748
Convertible Debt | 0.5% Convertible Senior Notes Due 2033
Antidilutive Securities Excluded from Computation of Earnings Per Share
Antidilutive securities excluded from computation of earnings per share	0	[1]	0	[1]
[1]	0.50% Convertible Senior Notes due 2033 were excluded from the calculation of diluted earnings per share under the treasury stock method since the conversion price exceeded the average market price for the Company's common stock.

Intangible_Assets_Including_Go2

Intangible Assets Including Goodwill - Schedule of Intangible Assets (Details) (USD $)	12 Months Ended
	3-May-15	Apr. 27, 2014	Apr. 28, 2013
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization of Intangible Assets	$8,700,000	$7,500,000	$10,900,000
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	131,811,000	130,076,000
Accumulated amoritzation	-108,523,000	-99,836,000
Total	23,288,000	30,240,000
Gross carrying amount	135,711,000	133,976,000
Net carrying amount	27,188,000	34,140,000
Purchased Technology
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	103,859,000	102,124,000
Accumulated amoritzation	-90,746,000	-85,007,000
Total	13,113,000	17,117,000
Purchased Trade Name
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	1,172,000	1,172,000
Accumulated amoritzation	-1,172,000	-1,172,000
Total	0	0
Purchased Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	21,344,000	21,344,000
Accumulated amoritzation	-13,648,000	-11,344,000
Total	7,696,000	10,000,000
Internal Use Software and Backlog
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	2,816,000	2,816,000
Accumulated amoritzation	-1,991,000	-1,666,000
Total	825,000	1,150,000
Purchased Patents
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	2,620,000	2,620,000
Accumulated amoritzation	-966,000	-647,000
Total	1,654,000	1,973,000
In-Process Research and Development
Indefinite-lived Intangible Assets
Gross and Net carrying amount	$3,900,000	$3,900,000

Intangible_Assets_Including_Go3

Intangible Assets Including Goodwill - Schedule of Expected Future Amortization Expense (Details) (USD $)	3-May-15	Apr. 27, 2014
In Thousands, unless otherwise specified
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2016	$8,413
2017	6,328
2018	4,218
2019	2,729
2020	1,251
2021 and beyond	349
Total	$23,288	$30,240

Intangible_Assets_Including_Go4

Intangible Assets Including Goodwill - Schedule of Goodwill (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	3-May-15	Apr. 27, 2014
Goodwill [Roll Forward]
Balance at beginning of period	$106,114	$90,986
Addition related to an acquisition	622	15,252
Goodwill allocated to asset disposal groups		-124
Balance at end of period	$106,736	$106,114

Investments_Details

Investments (Details) (USD $)	12 Months Ended
	3-May-15	Apr. 27, 2014
		privately_held_company
Minority Investment
Cost method investment	$884,000	$884,000
Number of companies (cost method)	1	1
Equity method investments	2,000,000	1,200,000
Number of companies (equity method)	1	1
Ownership percentage in equity method investment	19.90%
Other Income (Expense)
Minority Investment
Share of net income from equity method investment	$730,000

Investments_Schedule_of_HeldTo

Investments - Schedule of Held-To-Maturity Securities (Details) (USD $)	12 Months Ended
	3-May-15	Apr. 27, 2014	Apr. 28, 2013
Investments, Debt and Equity Securities [Abstract]
Realized gains (losses)	$0	$0	$0
Investment
Amortized cost	292,748,000	209,922,000
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Fair value	292,748,000	209,922,000
Commercial Paper
Investment
Amortized cost	0	89,922,000
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Fair value	0	89,922,000
Certificates of Deposit
Investment
Amortized cost	292,748,000	120,000,000
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Fair value	292,748,000	120,000,000
Short-Term Investments
Investment
Amortized cost	292,748,000	209,922,000
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Fair value	$292,748,000	$209,922,000

Inventories_Details

Inventories (Details) (USD $)	3-May-15	Apr. 27, 2014
In Thousands, unless otherwise specified
Inventory Disclosure [Abstract]
Raw materials	$57,757	$52,594
Work-in-process	146,773	126,181
Finished goods	79,140	80,984
Total inventories	283,670	259,759
Including: inventory consigned to others	$34,240	$31,998

Property_Equipment_and_Improve2

Property, Equipment and Improvements - Schedule of Property, Equipment and Improvements (Details) (USD $)	3 Months Ended
	Jan. 25, 2015	3-May-15	Apr. 27, 2014
Property, Plant and Equipment [Line Items]
Total		$671,717,000	$583,434,000
Accumulated depreciation and amortization		-355,940,000	-310,106,000
Property, equipment and improvements (net)		315,777,000	273,328,000
Impairment of long-lived assets	5,800,000
Land and Buildings
Property, Plant and Equipment [Line Items]
Total		68,286,000	49,995,000
Computer Equipment
Property, Plant and Equipment [Line Items]
Total		62,857,000	55,611,000
Office Equipment, Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Total		5,251,000	5,213,000
Machinery and Equipment
Property, Plant and Equipment [Line Items]
Total		493,224,000	435,262,000
Leasehold Property and Improvements
Property, Plant and Equipment [Line Items]
Total		$42,099,000	$37,353,000

Other_Accrued_Liabilities_Deta

Other Accrued Liabilities (Details) (USD $)	3-May-15	Apr. 27, 2014
In Thousands, unless otherwise specified
Other Liabilities Disclosure [Abstract]
Warranty accrual	$6,451	$5,744
Other liabilities	32,788	26,032
Total	$39,239	$31,776

Debt_Narrative_Details

Debt - Narrative (Details) (USD $)	1 Months Ended		12 Months Ended	1 Months Ended	12 Months Ended
	Oct. 31, 2014	Oct. 31, 2009	Apr. 30, 2011	Dec. 31, 2013	3-May-15	Apr. 27, 2014
		D
Debt Instrument [Line Items]
Conversion of stock, shares issued	3,748,473
Gain (loss) recognized on debt conversion	$0
5.0% Convertible Senior Notes Due 2029
Debt Instrument [Line Items]
Interest rate					5.00%	5.00%
0.5% Convertible Senior Notes Due 2033
Debt Instrument [Line Items]
Interest rate				0.50%	0.50%	0.50%
Convertible Debt | 5.0% Convertible Senior Notes Due 2029
Debt Instrument [Line Items]
Debt instrument, face amount		100,000,000	40,000,000			40,000,000
Interest rate		5.00%
Convertible debt, threshold trading days		20
Convertible debt, threshold consecutive trading days		30 days
Convertible debt, threshold percentage of stock price trigger		130.00%
Convertible debt, threshold trading days within notice of redemption		5 days
Convertible debt, conversion ratio		0.0936768
Convertible debt, conversion ratio		$10.68
Aggregate principal amount of debt exchanged			60,000,000
Convertible Debt | 5.0% Convertible Senior Notes Due 2029 | Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Debt redemption price percentage		100.00%
Convertible Debt | 5.0% Convertible Senior Notes Due 2029 | Debt Instrument, Redemption, Period Two
Debt Instrument [Line Items]
Debt redemption price percentage		100.00%
Convertible Debt | 5.0% Convertible Senior Notes Due 2029 | Debt Instrument, Redemption, Period Three
Debt Instrument [Line Items]
Debt redemption price percentage		100.00%
Convertible Debt | 5.0% Convertible Senior Notes Due 2029 | Debt Instrument, Redemption, Period Four
Debt Instrument [Line Items]
Debt redemption price percentage		100.00%
Convertible Debt | 5.0% Convertible Senior Notes Due 2029 | Debt Instrument, Redemption, Period Five
Debt Instrument [Line Items]
Debt redemption price percentage		100.00%
Convertible Debt | 5.0% Convertible Senior Notes Due 2029 | Debt Instrument, Redemption, Period Six
Debt Instrument [Line Items]
Debt redemption price percentage		100.00%
Convertible Debt | 0.5% Convertible Senior Notes Due 2033
Debt Instrument [Line Items]
Debt instrument, face amount				258,800,000
Convertible debt, conversion ratio				0.0331031
Convertible debt, conversion ratio				$30.18
Carrying amount of liability component				209,100,000
Carrying amount of the equity component				49,600,000	49,648,000
Convertible debt, remaining discount amortization period					43 months
Debt issuance cost					3,800,000
Convertible Debt | 0.5% Convertible Senior Notes Due 2033 | Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Debt redemption price percentage				100.00%
Convertible Debt | 0.5% Convertible Senior Notes Due 2033 | Debt Instrument, Redemption, Period Two
Debt Instrument [Line Items]
Debt redemption price percentage				100.00%
Convertible Debt | 0.5% Convertible Senior Notes Due 2033 | Debt Instrument, Redemption, Period Three
Debt Instrument [Line Items]
Debt redemption price percentage				100.00%
Convertible Debt | 0.5% Convertible Senior Notes Due 2033 | Debt Instrument, Redemption, Period Five
Debt Instrument [Line Items]
Debt redemption price percentage				100.00%
Convertible Debt | 0.5% Convertible Senior Notes Due 2033 | Debt Instrument, Conversion, Option One
Debt Instrument [Line Items]
Convertible debt, threshold trading days				20
Convertible debt, threshold consecutive trading days				30 days
Convertible debt, threshold percentage of stock price trigger				130.00%
Convertible Debt | 0.5% Convertible Senior Notes Due 2033 | Debt Instrument, Conversion, Option Two
Debt Instrument [Line Items]
Convertible debt, threshold trading days				5
Convertible debt, threshold consecutive trading days				5 days
Convertible debt, threshold percentage of stock price trigger				98.00%
Convertible Debt | 0.5% Convertible Senior Notes Due 2033 | Other Noncurrent Assets
Debt Instrument [Line Items]
Debt issuance cost					3,100,000
Convertible Debt | 0.5% Convertible Senior Notes Due 2033 | Additional Paid-in Capital
Debt Instrument [Line Items]
Debt issuance cost					$725,000

Debt_Schedule_of_Convertible_D

Debt - Schedule of Convertible Debt (Details) (USD $)	3-May-15	Apr. 27, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Debt Instrument [Line Items]
Convertible debt, net of current portion	221,406	$212,253
Current portion of convertible debt	0	40,015
Convertible Debt	221,406	252,268
0.5% Convertible Senior Notes Due 2033
Debt Instrument [Line Items]
Convertible debt, net of current portion		212,253
Interest rate	0.50%	0.50%	0.50%
5.0% Convertible Senior Notes Due 2029
Debt Instrument [Line Items]
Current portion of convertible debt		$40,015
Interest rate	5.00%	5.00%

Debt_2033_Notes_Details

Debt - 2033 Notes (Details) (USD $)	3-May-15	Apr. 27, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Debt Instrument [Line Items]
Net carrying amount of the liability component	$221,406	$252,268
Convertible Debt | 0.5% Convertible Senior Notes Due 2033
Debt Instrument [Line Items]
Principle	258,750
Unamortized debt discount	-37,344
Net carrying amount of the liability component	221,406
Carrying amount of the equity component	$49,648		$49,600

Debt_Interest_Expense_Details

Debt - Interest Expense (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	3-May-15	Apr. 27, 2014	Apr. 28, 2013
Debt Instrument [Line Items]
Amortization of the debt discount	$9,153	$3,151	$0
0.5% Convertible Senior Notes Due 2033 | Convertible Debt
Debt Instrument [Line Items]
Contractual interest expense	1,294
Amortization of the debt discount	9,153
Amortization of issuance costs	616
Total interest cost	$11,063
Liability [Member] | 0.5% Convertible Senior Notes Due 2033 | Convertible Debt
Debt Instrument [Line Items]
Effective interest rate on the liability component	4.87%

Commitments_Details

Commitments (Details) (USD $)	12 Months Ended
	3-May-15	Apr. 27, 2014	Apr. 28, 2013
Commitments and Contingencies Disclosure [Abstract]
Rent expense	$10,700,000	$10,000,000	$9,700,000
Sublease income	218,000	266,000	250,000
Operating Leases, Future Minimum Payments Due [Abstract]
Total	51,695,000
Less than 1 year	10,573,000
1-3 years	19,426,000
4-5 years	14,390,000
After 5 years	$7,306,000

Fair_Value_of_Financial_Instru2

Fair Value of Financial Instruments - Schedule of Fair Value Assets Measured on a Recurring Basis (Details) (USD $)	3-May-15	Apr. 27, 2014
In Thousands, unless otherwise specified	companies
Fair Value Disclosures [Abstract]
Minority investments	$2,847	$2,117
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Minority Investments, Number of Companies	2
Recurring | Carrying Amount
Financial assets [Abstract]
Total	292,944	240,091
Recurring | Carrying Amount | Money Market Funds
Financial assets [Abstract]
Cash and cash equivalents	196	30,169
Recurring | Carrying Amount | Commercial Paper
Financial assets [Abstract]
Investments	0	89,922
Recurring | Carrying Amount | Certificates of Deposit
Financial assets [Abstract]
Investments	292,748	120,000
Recurring | Fair Value
Financial assets [Abstract]
Total	292,944	240,091
Recurring | Fair Value | Level 1
Financial assets [Abstract]
Total	196	30,169
Recurring | Fair Value | Level 2
Financial assets [Abstract]
Total	292,748	209,922
Recurring | Fair Value | Level 3
Financial assets [Abstract]
Total	0	0
Recurring | Fair Value | Money Market Funds
Financial assets [Abstract]
Cash and cash equivalents	196	30,169
Recurring | Fair Value | Money Market Funds | Level 1
Financial assets [Abstract]
Cash and cash equivalents	196	30,169
Recurring | Fair Value | Money Market Funds | Level 2
Financial assets [Abstract]
Cash and cash equivalents	0	0
Recurring | Fair Value | Money Market Funds | Level 3
Financial assets [Abstract]
Cash and cash equivalents	0	0
Recurring | Fair Value | Commercial Paper
Financial assets [Abstract]
Investments	0	89,922
Recurring | Fair Value | Commercial Paper | Level 1
Financial assets [Abstract]
Investments	0	0
Recurring | Fair Value | Commercial Paper | Level 2
Financial assets [Abstract]
Investments	0	89,922
Recurring | Fair Value | Commercial Paper | Level 3
Financial assets [Abstract]
Investments	0	0
Recurring | Fair Value | Certificates of Deposit
Financial assets [Abstract]
Investments	292,748	120,000
Recurring | Fair Value | Certificates of Deposit | Level 1
Financial assets [Abstract]
Investments	0	0
Recurring | Fair Value | Certificates of Deposit | Level 2
Financial assets [Abstract]
Investments	292,748	120,000
Recurring | Fair Value | Certificates of Deposit | Level 3
Financial assets [Abstract]
Investments	$0	$0

Fair_Value_of_Financial_Instru3

Fair Value of Financial Instruments - Schedule of Fair Value Liabilities on a Recurring Basis (Details) (Recurring, USD $)	3-May-15	Apr. 27, 2014
In Thousands, unless otherwise specified
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total	$221,406	$252,268
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total	264,364	409,412
Level 1 | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total	264,364	409,430
Level 2 | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total	0	0
Level 3 | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total	0	0
5.0% Convertible Senior Notes Due 2029 | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Convertible debt	0	40,015
5.0% Convertible Senior Notes Due 2029 | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Convertible debt	0	104,105
5.0% Convertible Senior Notes Due 2029 | Level 1 | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Convertible debt	0	104,105
5.0% Convertible Senior Notes Due 2029 | Level 2 | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Convertible debt	0	0
5.0% Convertible Senior Notes Due 2029 | Level 3 | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Convertible debt	0	0
0.5% Convertible Senior Notes Due 2033 | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Convertible debt	221,406	212,253
0.5% Convertible Senior Notes Due 2033 | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Convertible debt	264,364	305,307
0.5% Convertible Senior Notes Due 2033 | Level 1 | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Convertible debt	264,364	305,325
0.5% Convertible Senior Notes Due 2033 | Level 2 | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Convertible debt	0	0
0.5% Convertible Senior Notes Due 2033 | Level 3 | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Convertible debt	$0	$0

Stockholders_Equity_Details

Stockholders' Equity (Details) (USD $)	1 Months Ended	12 Months Ended
	Sep. 30, 2009	3-May-15	Apr. 27, 2014
Common Stock and Preferred Stock [Abstract]
Common stock, shares authorized		750,000,000	750,000,000
Common stock, par value		0.001	$0.00
Preferred stock, shares authorized		5,000,000	5,000,000
Preferred stock, par value		0.001	$0.00
Common stock, number of votes per share		1
Common Stock Subject to Future Issuance [Abstract]
Exercise of outstanding options		2,283,162	2,621,844
Vesting of restricted stock awards		6,611,614
Available for grant under employee stock option plans		13,023,873
Available for grant under stock purchase plan		4,249,965
Total		26,168,614
2009 Employee Stock Purchase Plan
Employee Stock Purchase Plan [Abstract]
Number of shares authorized under the plan	7,000,000
Maximum employee subscription rate	20.00%
Purchase price of common stock, discounted percentage	85.00%
2005 Plan
Employee Stock Purchase Plan [Abstract]
Number of shares authorized under the plan	22,500,000
Employee Stock Plans [Abstract]
Award vesting period		5 years
Stock option term, maximum		10 years
Restricted Stock Units
Common Stock Subject to Future Issuance [Abstract]
Vesting of restricted stock awards		6,611,614	6,516,317
Restricted Stock Units | 2005 Plan
Employee Stock Plans [Abstract]
Award vesting period		4 years

Stockholders_Equity_Schedule_o

Stockholders' Equity - Schedule of Stock Options (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	3-May-15	Apr. 27, 2014	Apr. 28, 2013
Number of Shares (in shares):
Options outstanding, beginning	2,621,844
Options exercised	-299,517
Options canceled	-39,165
Options outstanding, ending	2,283,162	2,621,844
Weighted-Average Exercise Price (in dollars per share):
Options outstanding, beginning, weighted average exercise price	$14.28
Options exercised, weighted average exercise price	$10.27
Options canceled, weighted average exercise price	$23.61
Options outstanding, ending weighted average exercise price	$14.64	$14.28
Options exercised, aggregate intrinsic value	$3.40	$14.20	$4.40
Options outstanding, intrinsic value	$19.50
Options outstanding ending, weighted average remaining contractual term	2 years 8 months 12 days

Stockholders_Equity_Schedule_o1

Stockholders' Equity - Schedule of Restricted Stock Units (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	3-May-15	Apr. 27, 2014	Apr. 28, 2013
Number of Shares (in shares):
Nonvested, ending, shares	6,611,614
Restricted Stock Units
Number of Shares (in shares):
Nonvested, beginning, shares	6,516,317
Granted, shares	2,831,517
Vested, shares	-2,350,245
Forfeited, shares	-385,975
Nonvested, ending, shares	6,611,614	6,516,317
Weighted-Average Grant-Date Fair Value (in dollars per share):
Nonvested, beginning, weighted average grant date fair value	$15.44
Granted, weighted average grant date fair value	$19.55	$16.91	$13.03
Vested, weighted average grant date fair value	$15.42
Forfeited, weighted average grant date fair value	$17.04
Nonvested, ending, weighted average grant date fair value	$17.12	$15.44
Aggregate intrinsic value of restricted stock units outstanding	$138.50
Fair value of restricted stock units that vested during the period	36.3	30.4	17.7
Unrecognized compensation expense related to RSUs	$74.20
Period for recognition of unrecognized compensation related to RSUs	27 months

Stockholders_Equity_Schedule_o2

Stockholders' Equity - Schedule of Share-Based Compensation Cost by Caption (Details) (USD $)	12 Months Ended
	3-May-15	Apr. 27, 2014	Apr. 28, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$44,600,000	$37,966,000	$31,961,000
Stock-based compensation capitalized as part of inventory	2,300,000	1,700,000
Cost of revenues
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	9,908,000	8,261,000	6,915,000
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	17,764,000	14,660,000	10,970,000
Sales and marketing
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	6,251,000	5,083,000	3,743,000
General and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$10,677,000	$9,962,000	$10,333,000

Stockholders_Equity_Schedule_o3

Stockholders' Equity - Schedule of Share-Based Compensation Cost by Type of Award (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	3-May-15	Apr. 27, 2014	Apr. 28, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$44,600	$37,966	$31,961
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	0	693	1,892
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	41,729	34,506	26,794
Employee stock purchase rights under ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$2,871	$2,767	$3,275

Stockholders_Equity_Schedule_o4

Stockholders' Equity - Schedule of Employee Stock Purchase Plan Valuation Assumptions (Details) (2009 Employee Stock Purchase Plan, USD $)	12 Months Ended
	3-May-15	Apr. 27, 2014	Apr. 28, 2013
2009 Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	9 months	9 months	9 months
Volatility, minimum	34.00%	40.00%	50.00%
Volatility, maximum	53.00%	47.00%	53.00%
Risk-free interest rate, minimum	0.07%	0.01%	0.10%
Risk-free interest rate, maximum	0.21%	0.13%	0.15%
Dividend yield	0.00%	0.00%	0.00%
Weighted average grant date fair value of options granted in the period	$3.06	$3.69	$2.81

Employee_Benefit_Plan_Details

Employee Benefit Plan (Details) (USD $)	12 Months Ended
	3-May-15	Dec. 31, 2014	Apr. 27, 2014	Dec. 31, 2013	Apr. 28, 2013	Dec. 31, 2015
Defined Benefit Plan Disclosure
Maximum statutory contribution by employee (percentage of gross)	20.00%
Maximum statutory contribution by employee (in usd)		$17,500		$17,500
Employer matching contribution (percentage of employee's match)	50.00%
Employer matching contribution (percentage of employee's match subject to employer match)	6.00%
Employer contribution in defined contribution retirement plan (in shares)	122,979
Employer contribution in defined contribution retirement plan (in usd)	2,400,000
Defined contribution plan expenses	2,600,000		2,200,000		1,900,000
Forecast
Defined Benefit Plan Disclosure
Maximum statutory contribution by employee (in usd)						$18,000

Income_Taxes_Details

Income Taxes (Details) (USD $)	12 Months Ended
	3-May-15	Apr. 27, 2014	Apr. 28, 2013
Operating Loss Carryforwards
Percentage of total deferred assets maintained as a valuation allowance	94.00%
Increase (decrease) in valuation allowance	$7,700,000	($74,200,000)	$5,000,000
Deferred tax assets	42,700,000
Tax Holiday affect on net income (in usd)	5,600,000
Tax Holiday affect on net income (in usd per share)	$0.05
Undistributed earnings of foreign subsidiaries	190,600,000
Federal statutory tax rate	35.00%	35.00%	35.00%
Unrecognized tax benefits that would impact fffective tax rate	12,600,000
Accrued interest or penalties	0
Federal
Operating Loss Carryforwards
Net operating loss carryforwards	375,300,000
Tax credit carryforwards	27,000,000
State
Operating Loss Carryforwards
Net operating loss carryforwards	50,100,000
Tax credit carryforwards	20,500,000
Foreign
Operating Loss Carryforwards
Net operating loss carryforwards	$40,300,000

Income_Taxes_Schedule_of_Compo

Income Taxes - Schedule of Components of Income Tax Expense (Benefit) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	3-May-15	Apr. 27, 2014	Apr. 28, 2013
Current:
Federal	$0	($385)	$0
State	209	523	-45
Foreign	8,814	5,691	3,896
Current income tax expense (benefit)	9,023	5,829	3,851
Deferred:
Federal	-607	0	0
State	-14	0	0
Foreign	393	-2,945	-3,624
Deferred income tax expense (benefit)	-228	-2,945	-3,624
Provision for income taxes	8,795	2,884	227
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest [Abstract]
U.S.	-29,300	46,314	-21,863
Foreign	49,982	68,107	14,025
Income (loss) before income taxes and non-controlling interest	$20,682	$114,421	($7,838)

Income_Taxes_Schedule_of_Effec

Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	3-May-15	Apr. 27, 2014	Apr. 28, 2013
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Expected income tax provision (benefit) at U.S. federal statutory rate	35.00%	35.00%	35.00%
Foreign rate differential	-46.90%	-18.30%	38.30%
Share-based compensation expense	29.60%	2.50%	-45.20%
Non-deductible transaction costs	0.50%	0.40%	-5.80%
Non-recurring acquisition-related gain	0.00%	0.00%	31.10%
Valuation allowance	49.10%	-21.40%	-101.00%
Intangibles impairment	0.00%	0.00%	36.80%
Research and development credits	-15.00%	-1.80%	18.70%
Non-deductible acquisition-related charge	0.00%	0.00%	-6.20%
Other	-9.80%	6.10%	-4.60%
Effective income tax rate	42.50%	2.50%	-2.90%

Income_Taxes_Schedule_of_Defer

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) (USD $)	3-May-15	Apr. 27, 2014	Apr. 28, 2013
In Thousands, unless otherwise specified
Deferred tax assets:
Inventory adjustments	$10,024	$8,905	$9,170
Accruals and reserves	13,081	18,673	14,194
Tax credits	27,836	24,259	21,869
Net operating loss carryforwards	101,850	95,952	155,281
Gain/loss on investments under equity or cost method	8,367	8,843	8,931
Depreciation and amortization	4,509	2,817	1,915
Purchase accounting for intangible assets	4,438	5,651	190
Capital loss carryforward	172	229	563
Acquired intangibles	8,208	10,142	18,356
Stock compensation	9,302	8,372	7,917
Total deferred tax assets	187,787	183,843	238,386
Valuation allowance	-161,358	-153,657	-227,889
Net deferred tax assets	26,429	30,186	10,497
Deferred tax liabilities:
Acquired intangibles	-5,597	-7,252	-5,128
Debt discount	-13,862	-16,873	-1,592
Inventory reserve	-513	-457	-1,791
Depreciation and amortization	-7,068	-5,762	-774
Total deferred tax liabilities	-27,040	-30,344	-9,285
Total net deferred tax assets (liabilities)	($611)	($158)	$1,212

Income_Taxes_Summary_of_Moveme

Income Taxes - Summary of Movement in Gross Unrecognized Tax Benefits (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	3-May-15	Apr. 27, 2014	Apr. 28, 2013
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	$13,432	$15,632	$14,634
Additions for tax positions related to current year	975	712	241
Additions for tax positions related to prior years	246	0	757
Reductions for tax positions related to prior years (lapse of statute of limitations)	0	-2,912	0
Ending balance	$14,653	$13,432	$15,632

Segments_and_Geography_Informa2

Segments and Geography Information - Schedule of Revenue from External Customers and Long-Lived Assets, by Geographic Area (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	3-May-15	Apr. 27, 2014	Apr. 28, 2013
	Segments
Segment Reporting [Abstract]
Number of reportable segments	1
Segment Reporting Information
Revenues	$1,250,944	$1,156,833	$934,335
Long-lived assets	380,882	326,858
United States
Segment Reporting Information
Revenues	425,066	339,423	269,071
Long-lived assets	122,118	110,573
Malaysia
Segment Reporting Information
Revenues	148,258	185,197	183,299
Long-lived assets	54,480	56,007
China
Segment Reporting Information
Revenues	242,916	229,231	171,016
Long-lived assets	175,580	127,966
Rest of the World
Segment Reporting Information
Revenues	434,704	402,982	310,949
Long-lived assets	$28,704	$32,312

Litigation_Disclosure_Litigati

Litigation Disclosure - Litigation (Details) (USD $)	3 Months Ended	0 Months Ended	1 Months Ended	6 Months Ended
In Millions, unless otherwise specified	Oct. 26, 2014	Feb. 26, 2013	Oct. 31, 2014	Oct. 26, 2014	Mar. 08, 2011
		patent			lawsuit
Loss Contingencies [Line Items]
Litigation settlement	($11)
Thomas Swan
Loss Contingencies [Line Items]
Loss contingency, number of patents		4
Payments for legal settlement			11
Pending Litigation | Earnings Announcements Cases
Loss Contingencies [Line Items]
Loss contingency pending claims					2
Pending Litigation | Derivative Lawsuit
Loss Contingencies [Line Items]
Loss contingency pending claims					1
Selling, General and Administrative Expenses | Thomas Swan
Loss Contingencies [Line Items]
Litigation settlement				($11)

Restructuring_Charges_Schedule

Restructuring Charges - Schedule of Restructuring Reserve (Details) (USD $)	3 Months Ended	12 Months Ended
	Nov. 01, 2009	3-May-15
Restructuring and Related Activities [Abstract]
Restructuring charges	$4,200,000
Restructuring Reserve [Roll Forward]
Balance as of April 27, 2014		2,911,000
Cash payments, net of sublease income		-351,000
Balance as of May 3, 2015		2,560,000
Restructuring Reserve [Abstract]
Restructuring accrual expected to be paid in the next twelve months		390,000
Restructuring accrual expected to be paid out from 2014 through 2020		$2,200,000

Warranty_Details

Warranty (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	3-May-15	Apr. 27, 2014
Movement in Standard Product Warranty Accrual [Roll Forward]
Beginning balance	$5,744	$4,155
Additions during the period based on product sold	6,171	5,653
Additions during the period due to acquisitions	0	515
Change in estimates	-1,388	-2,022
Settlements and expirations	-4,076	-2,557
Ending balance	$6,451	$5,744

Related_Parties_Details

Related Parties (Details) (Immediate Family Member of Management, USD $)	12 Months Ended
	3-May-15	Apr. 27, 2014	Apr. 28, 2013	Jun. 24, 2014	Jun. 18, 2013	Jun. 23, 2015
Related Party Transaction
Related party transaction expense	$140,696	$195,164	$216,723
Restricted Stock Units
Related Party Transaction
Restricted Stock Units granted to related party (in shares)	2,305	4,164	3,814
Fair value of Restricted Stock Units granted to related party	$45,132	$66,957	$49,086
Year 1 Percentage | Restricted Stock Units
Related Party Transaction
Related party transaction, vesting rate of Restricted Stock Units				25.00%	25.00%
Year 2 Percentage | Restricted Stock Units
Related Party Transaction
Related party transaction, vesting rate of Restricted Stock Units	25.00%	25.00%	25.00%
Year 3 Percentage | Restricted Stock Units
Related Party Transaction
Related party transaction, vesting rate of Restricted Stock Units	25.00%	25.00%	25.00%
Year 4 Percentage | Restricted Stock Units
Related Party Transaction
Related party transaction, vesting rate of Restricted Stock Units	25.00%	25.00%	25.00%
Subsequent Event | Year 1 Percentage | Restricted Stock Units
Related Party Transaction
Related party transaction, vesting rate of Restricted Stock Units						25.00%

Guarantees_and_Indemnification1

Guarantees and Indemnifications (Details)	12 Months Ended
	3-May-15
Guarantees [Abstract]
Period of written notification to terminate agreement	90 days

Financial_Information_by_Quart2

Financial Information by Quarter (Unaudited) (Details) (USD $)	3 Months Ended								12 Months Ended
Share data in Thousands, except Per Share data, unless otherwise specified	3-May-15	Jan. 25, 2015	Oct. 26, 2014	Jul. 27, 2014	Apr. 27, 2014	Jan. 26, 2014	Oct. 27, 2013	Jul. 28, 2013	3-May-15	Apr. 27, 2014	Apr. 28, 2013
Quarterly Financial Information Disclosure [Abstract]
Revenues	$320,042,000	$306,283,000	$296,981,000	$327,638,000	$306,025,000	$294,018,000	$290,722,000	$266,068,000
Gross profit	89,217,000	77,953,000	84,921,000	98,819,000	96,564,000	105,689,000	103,373,000	91,373,000	350,910,000	396,999,000	257,041,000
Income (loss) from operations	10,284,000	3,401,000	-7,259,000	20,368,000	21,107,000	33,096,000	30,109,000	27,103,000	26,794,000	111,415,000	-5,555,000
Income (loss) before non-controlling interest	7,327,000	1,678,000	-11,361,000	14,243,000	28,683,000	27,068,000	29,951,000	25,835,000
Net income (loss) attributable to Finisar Corporation	7,327,000	1,678,000	-11,361,000	14,243,000	28,750,000	27,061,000	29,965,000	26,011,000	11,887,000	111,787,000	-5,454,000
Net income (loss) per share attributable to Finisar Corporation common stockholders:
Basic (in usd)	$0.07	$0.02	($0.11)	$0.14	$0.30	$0.28	$0.31	$0.27	$0.12	$1.16	($0.06)
Diluted (in usd)	$0.07	$0.02	($0.11)	$0.14	$0.28	$0.26	$0.29	$0.26	$0.11	$1.09	($0.06)
Shares used in computing net income (loss) per share:
Basic (in shares)	104,005	103,563	99,621	98,241	96,965	96,394	95,941	94,609	101,408	95,979	92,860
Diluted (in shares)	107,535	105,990	99,621	106,036	105,418	104,361	103,696	101,125	104,970	104,112	92,860
Impairment of long-lived assets		5,800,000
Litigation settlement			-11,000,000
Gain on divestiture of majority-owned subsidiary					8,200,000
Gain (loss) related to litigation settlement								$6,500,000

Schedule_II_Consolidated_Valua1

Schedule II - Consolidated Valuation and Qualifying Accounts (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	3-May-15	Apr. 27, 2014	Apr. 28, 2013
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$929	$958	$1,311
Additions charged to costs and expenses	207	101	-268
Write-Offs	0	-130	-85
Balance at End of Period	$1,136	$929	$958