Pending Litigation	6 Months Ended
Oct. 30, 2011
Loss Contingency, Information about Litigation Matters [Abstract]
Pending Litigation [Text Block]	Pending Litigation The Company is a party to several pending legal proceedings described below. In each of these proceedings in which the Company is a defendant, the Company believes that it has strong defenses and intends to vigorously defend the action. As of the date of this report, the Company does not believe it is reasonably likely that losses related to any of these cases have occurred beyond the amounts, if any, that have been accrued. However, the litigation process is inherently uncertain, and, accordingly, the Company cannot predict the outcome of any of these matters with certainty. Future developments in one or more of these matters may cause the Company to revise its estimates and related accruals in future periods. Oplink/OCP Patent Litigation On December 10, 2010, the Company filed a complaint for patent infringement in the United States District Court for the Northern District of California. The complaint alleges that certain optoelectronic transceivers from Oplink Communications, Inc. ("Oplink") and its wholly-owned subsidiary Optical Communication Products Inc. ("OCP") infringe eleven Finisar patents. The complaint asks the Court to enter judgment (a) that the defendants have infringed, actively induced infringement of, and/or contributorily infringed the patents-in-suit, (b) preliminarily and permanently enjoining the defendants from further infringement of the patents-in-suit, or, to the extent not so enjoined, ordering the defendants to pay compulsory ongoing royalties for any continuing infringement, (c) ordering that the defendants account, and pay actual damages (but no less than a reasonable royalty), to the Company for the defendants' infringement, (d) declaring that the defendants are willfully infringing one or more of the patents-in-suit and ordering that the defendants pay treble damages to the Company, (e) ordering that the defendants pay the Company's costs, expenses, and interest, including prejudgment interest, (f) declaring that this is an exceptional case and awarding the Company its attorneys' fees and expenses, and (g) granting such other and further relief as the Court deems just and appropriate, or that the Company may be entitled to as a matter of law or equity. On March 7, 2011, OCP filed a complaint against the Company for patent infringement in the United States District Court for the Eastern District of Texas. The complaint alleges that certain vertical cavity surface emitting lasers ("VCSELs") and active optical cables manufactured and sold by the Company infringe five OCP patents. The Company has answered the complaint denying that it has infringed any of these patents and asserting that the patents are invalid. In addition, the Company has counterclaimed in the case that certain optoelectronic transceivers from OCP and its parent Oplink infringe five Finisar patents. The complaint and the counter complaints each ask the Court to enter judgment (a) holding the accused party(ies) liable for infringement of the asserted patents, (b) that the accused party(ies) account for damages resulting from its infringement of the patents, together with pre-judgment and post-judgment interest, (c) preliminarily and permanently enjoining the accused party(ies) from further infringement of the asserted patents, (d) holding the case to an exceptional case, and awarding to the complaining party its attorneys' fees and costs, and (e) granting such other relief as the Court deems just and equitable. The Company intends to prosecute its lawsuit against Oplink and defend OCP's lawsuit vigorously. However, there can be no assurance that it will be successful in its defense. The Company is not currently able to estimate a range of possible losses if it is not successful in defending the OCP lawsuit. However, if it is not successful, the Company's business could be materially harmed. Even if the Company is successful, it 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. On May 13, 2011, Oplink and OCP filed a complaint in the United States District Court for the Northern District of California seeking a declaration that the products accused of infringement by the Company as counterclaims in the Texas lawsuit do not infringe the asserted patents. The Company is seeking dismissal of this action as the patents and the accused products are subject to the Texas proceeding. Class Action and Shareholder Derivative Litigation March 8, 2011 Earnings Announcement Cases 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 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 have consolidated and lead plaintiffs have been appointed to file a consolidated complaint. In addition, two shareholder derivative lawsuits related to the Company's March 8, 2011 earnings announcement were filed in California state court. 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 its board of directors, including the Company's Chairman of the Board, Chief Executive Officer and our Chief Financial Officer. No specific amount of damages have been alleged and, by the derivative nature of the lawsuits, no damages will be alleged, against the Company. The cases have been consolidated and a lead plaintiff has been appointed to file a consolidated complaint. Stock Option Cases On November 30, 2006, the Company announced that it had undertaken a voluntary review of its historical stock option grant practices subsequent to its initial public offering in November 1999. The review was initiated by senior management, and preliminary results of the review were discussed with the Audit Committee of the Company's board of directors. Based on the preliminary results of the review, senior management concluded, and the Audit Committee agreed, that it was likely that the measurement dates for certain stock option grants differed from the recorded grant dates for such awards and that the Company would likely need to restate its historical financial statements to record non-cash charges for compensation expense relating to some past stock option grants. The Audit Committee thereafter conducted a further investigation and engaged independent legal counsel and financial advisors to assist in that investigation. The Audit Committee concluded that measurement dates for certain option grants differed from the recorded grant dates for such awards. The Company's management, in conjunction with the Audit Committee, conducted a further review to finalize revised measurement dates and determine the appropriate accounting adjustments to its historical financial statements. The announcement of the investigation resulted in delays in filing the Company's quarterly reports on Form 10-Q for the quarters ended October 29, 2006, January 28, 2007, and January 27, 2008, and the Company's annual report on Form 10-K for the fiscal year ended April 30, 2007. On December 4, 2007, the Company filed all four of these reports which included revised financial statements. Following the Company's announcement on November 30, 2006 that the Audit Committee of the board of directors had voluntarily commenced an investigation of the Company's historical stock option grant practices, the Company was named as a nominal defendant in several shareholder derivative cases. These cases have been consolidated into two proceedings pending in federal and state courts in California. The federal court cases have been consolidated in the United States District Court for the Northern District of California. The state court cases have been consolidated in the Superior Court of California for the County of Santa Clara. The plaintiffs in all cases have alleged that certain of the Company's current or former officers and directors caused the Company to grant stock options at less than fair market value, contrary to the Company's public statements (including its financial statements), and that, as a result, those officers and directors are liable to the Company. No specific amount of damages has been alleged, and by the nature of the lawsuits, no damages will be alleged against the Company. On May 22, 2007, the state court granted the Company's motion to stay the state court action pending resolution of the consolidated federal court action. On June 12, 2007, the plaintiffs in the federal court case filed an amended complaint to reflect the results of the stock option investigation announced by the Audit Committee in June 2007. On August 28, 2007, the Company and the individual defendants filed motions to dismiss the complaint. On January 11, 2008, the Court granted the motions to dismiss, with leave to amend. On May 12, 2008, the plaintiffs filed an amended complaint. The Company and the individual defendants filed motions to dismiss the amended complaint on July 1, 2008. The Court granted the motions to dismiss on September 22, 2009, and entered judgment in favor of the defendants. The plaintiffs appealed the judgment to the United States Court of Appeals for the Ninth Circuit. On April 26, 2011, a panel of the Ninth Circuit reversed the District Court ruling and remanded the case to the District Court for further proceedings. The Company and the individual defendants filed a motion seeking rehearing of the case en banc before the full Ninth Circuit, which was denied on July 8, 2011. Cheetah Omni Litigation On July 29, 2011, Cheetah Omni LLC filed a complaint for patent infringement in the United States District Court for the Eastern District of Texas against Alcatel-Lucent USA Inc., Alcatel-Lucent Holdings, Inc., Ciena Corporation, Ciena Communications, Inc., Fujitsu Network Communications, Inc., Tellabs, Inc., Tellabs Operations, Inc., Tellabs North America, Inc., Nokia Siemens Networks US LLC, Huawei Technologies USA, Inc. and Huawei Device USA, Inc. Finisar was not named as a defendant in the lawsuit. However, the named defendants or entities affiliated with them are Finisar customers. The complaint alleges that certain ROADM products of the named defendants infringe one or more of seven Cheetah Omni patents. With respect to two of the seven patents, the Company understands Cheetah Omni to be asserting infringement by the customer defendants' making, using, offering for sale, selling, and/or importing into the United States certain ROADM products that include a Finisar wavelength selective switch (WSS). Finisar has no specific information regarding whether the claims of infringement with respect to the remaining five asserted Cheetah Omni patents implicate any Finisar products. To date, Finisar has received a request for indemnification from two customers with respect to the two patents mentioned above and may receive additional requests in the future. The Company is currently evaluating the request for indemnification. The Company also expects that the defendant customers will defend the lawsuit vigorously at least with respect to the claims that implicate any Finisar products. However, there can be no assurance that they will be successful in their defense and, if they are not successful with respect to the two patents mentioned above, Finisar may be liable to indemnify the accused customers for significant damages. Even if the defense is successful, the Company may incur substantial legal fees and other costs in defending and/or aiding in the defense of the lawsuit with respect to the two patents mentioned above. Further, the lawsuit could divert the efforts and attention of the Company's management and technical personnel, which could harm its business. Securities Class Action A securities class action lawsuit was filed on November 30, 2001 in the United States District Court for the Southern District of New York, purportedly on behalf of all persons who purchased the Company's common stock from November 17, 1999 through December 6, 2000. The complaint named as defendants the Company, Jerry S. Rawls, its Chairman of the Board and formerly its President and Chief Executive Officer, Frank H. Levinson, its former Chairman of the Board and Chief Technical Officer, Stephen K. Workman, its former Senior Vice President and Chief Financial Officer, and an investment banking firm that served as an underwriter for the Company's initial public offering in November 1999 and a secondary offering in April 2000. The complaint, as subsequently amended, alleges violations of Sections 11 and 15 of the Securities Act of 1933 and Sections 10(b) and 20(b) of the Securities Exchange Act of 1934, on the grounds that the prospectuses incorporated in the registration statements for the offerings failed to disclose, among other things, that (i) the underwriter had solicited and received excessive and undisclosed commissions from certain investors in exchange for which the underwriter allocated to those investors material portions of the shares of the Company's stock sold in the offerings and (ii) the underwriter had entered into agreements with customers whereby the underwriter agreed to allocate shares of the Company's stock sold in the offerings to those customers in exchange for which the customers agreed to purchase additional shares of the Company's stock in the after market at pre-determined prices. No specific damages are claimed. Similar allegations have been made in lawsuits relating to more than 300 other initial public offerings conducted in 1999 and 2000, which were consolidated for pretrial purposes. In October 2002, all claims against the individual defendants were dismissed without prejudice. On February 19, 2003, the Court denied defendants' motion to dismiss the complaint. In February 2009, the parties reached an understanding regarding the principal elements of a settlement, subject to formal documentation and Court approval. Under the settlement, the underwriter defendants will pay a total of $486 million, and the issuer defendants and their insurers will pay a total of $100 million to settle all of the cases. On August 25, 2009, the Company funded approximately $327,000 with respect to its pro rata share of the issuers' contribution to the settlement and certain costs. This amount was accrued in the Company's consolidated financial statements during the first quarter of fiscal 2010. On October 2, 2009, the Court granted approval of the settlement and on November 19, 2009 the Court entered final judgment. The judgment has been appealed by certain individual class members. Other During the second quarter of fiscal 2012, the Company received a favorable arbitrator's decision in an intellectual property legal dispute unrelated to current or future quarters awarding the Company $7.4 million. As litigation related to the decision is ongoing, no amounts were recognized in the Company's consolidated financial statements as of, and for the three- and six-month periods ending, October 30, 2011. 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.

Pending Litigation

The Company is a party to several pending legal proceedings described below. In each of these proceedings in which the Company is a defendant, the Company believes that it has strong defenses and intends to vigorously defend the action. As of the date of this report, the Company does not believe it is reasonably likely that losses related to any of these cases have occurred beyond the amounts, if any, that have been accrued. However, the litigation process is inherently uncertain, and, accordingly, the Company cannot predict the outcome of any of these matters with certainty. Future developments in one or more of these matters may cause the Company to revise its estimates and related accruals in future periods.

Oplink/OCP Patent Litigation

On December 10, 2010, the Company filed a complaint for patent infringement in the United States District Court for the Northern District of California. The complaint alleges that certain optoelectronic transceivers from Oplink Communications, Inc. ("Oplink") and its wholly-owned subsidiary Optical Communication Products Inc. ("OCP") infringe eleven Finisar patents. The complaint asks the Court to enter judgment (a) that the defendants have infringed, actively induced infringement of, and/or contributorily infringed the patents-in-suit, (b) preliminarily and permanently enjoining the defendants from further infringement of the patents-in-suit, or, to the extent not so enjoined, ordering the defendants to pay compulsory ongoing royalties for any continuing infringement, (c) ordering that the defendants account, and pay actual damages (but no less than a reasonable royalty), to the Company for the defendants' infringement, (d) declaring that the defendants are willfully infringing one or more of the patents-in-suit and ordering that the defendants pay treble damages to the Company, (e) ordering that the defendants pay the Company's costs, expenses, and interest, including prejudgment interest, (f) declaring that this is an exceptional case and awarding the Company its attorneys' fees and expenses, and (g) granting such other and further relief as the Court deems just and appropriate, or that the Company may be entitled to as a matter of law or equity.

On March 7, 2011, OCP filed a complaint against the Company for patent infringement in the United States District Court for the Eastern District of Texas. The complaint alleges that certain vertical cavity surface emitting lasers ("VCSELs") and active optical cables manufactured and sold by the Company infringe five OCP patents. The Company has answered the complaint denying that it has infringed any of these patents and asserting that the patents are invalid. In addition, the Company has counterclaimed in the case that certain optoelectronic transceivers from OCP and its parent Oplink infringe five Finisar patents.

The complaint and the counter complaints each ask the Court to enter judgment (a) holding the accused party(ies) liable for infringement of the asserted patents, (b) that the accused party(ies) account for damages resulting from its infringement of the patents, together with pre-judgment and post-judgment interest, (c) preliminarily and permanently enjoining the accused party(ies) from further infringement of the asserted patents, (d) holding the case to an exceptional case, and awarding to the complaining party its attorneys' fees and costs, and (e) granting such other relief as the Court deems just and equitable. The Company intends to prosecute its lawsuit against Oplink and defend OCP's lawsuit vigorously. However, there can be no assurance that it will be successful in its defense. The Company is not currently able to estimate a range of possible losses if it is not successful in defending the OCP lawsuit. However, if it is not successful, the Company's business could be materially harmed. Even if the Company is successful, it 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.

On May 13, 2011, Oplink and OCP filed a complaint in the United States District Court for the Northern District of California seeking a declaration that the products accused of infringement by the Company as counterclaims in the Texas lawsuit do not infringe the asserted patents. The Company is seeking dismissal of this action as the patents and the accused products are subject to the Texas proceeding.

Class Action and Shareholder Derivative Litigation

March 8, 2011 Earnings Announcement Cases

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 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 have consolidated and lead plaintiffs have been appointed to file a consolidated complaint.

In addition, two shareholder derivative lawsuits related to the Company's March 8, 2011 earnings announcement were filed in California state court. 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 its board of directors, including the Company's Chairman of the Board, Chief Executive Officer and our Chief Financial Officer. No specific amount of damages have been alleged and, by the derivative nature of the lawsuits, no damages will be alleged, against the Company. The cases have been consolidated and a lead plaintiff has been appointed to file a consolidated complaint.

Stock Option Cases

On November 30, 2006, the Company announced that it had undertaken a voluntary review of its historical stock option

grant practices subsequent to its initial public offering in November 1999. The review was initiated by senior management, and preliminary results of the review were discussed with the Audit Committee of the Company's board of directors. Based on the preliminary results of the review, senior management concluded, and the Audit Committee agreed, that it was likely that the measurement dates for certain stock option grants differed from the recorded grant dates for such awards and that the Company would likely need to restate its historical financial statements to record non-cash charges for compensation expense relating to some past stock option grants. The Audit Committee thereafter conducted a further investigation and engaged independent legal counsel and financial advisors to assist in that investigation. The Audit Committee concluded that measurement dates for certain option grants differed from the recorded grant dates for such awards. The Company's management, in conjunction with the Audit Committee, conducted a further review to finalize revised measurement dates and determine the appropriate accounting adjustments to its historical financial statements. The announcement of the investigation resulted in delays in filing the Company's quarterly reports on Form 10-Q for the quarters ended October 29, 2006, January 28, 2007, and January 27, 2008, and the Company's annual report on Form 10-K for the fiscal year ended April 30, 2007. On December 4, 2007, the Company filed all four of these reports which included revised financial statements.

Following the Company's announcement on November 30, 2006 that the Audit Committee of the board of directors had voluntarily commenced an investigation of the Company's historical stock option grant practices, the Company was named as a nominal defendant in several shareholder derivative cases. These cases have been consolidated into two proceedings pending in federal and state courts in California. The federal court cases have been consolidated in the United States District Court for the Northern District of California. The state court cases have been consolidated in the Superior Court of California for the County of Santa Clara. The plaintiffs in all cases have alleged that certain of the Company's current or former officers and directors caused the Company to grant stock options at less than fair market value, contrary to the Company's public statements (including its financial statements), and that, as a result, those officers and directors are liable to the Company. No specific amount of damages has been alleged, and by the nature of the lawsuits, no damages will be alleged against the Company. On May 22, 2007, the state court granted the Company's motion to stay the state court action pending resolution of the consolidated federal court action. On June 12, 2007, the plaintiffs in the federal court case filed an amended complaint to reflect the results of the stock option investigation announced by the Audit Committee in June 2007. On August 28, 2007, the Company and the individual defendants filed motions to dismiss the complaint. On January 11, 2008, the Court granted the motions to dismiss, with leave to amend. On May 12, 2008, the plaintiffs filed an amended complaint. The Company and the individual defendants filed motions to dismiss the amended complaint on July 1, 2008. The Court granted the motions to dismiss on September 22, 2009, and entered judgment in favor of the defendants. The plaintiffs appealed the judgment to the United States Court of Appeals for the Ninth Circuit. On April 26, 2011, a panel of the Ninth Circuit reversed the District Court ruling and remanded the case to the District Court for further proceedings. The Company and the individual defendants filed a motion seeking rehearing of the case en banc before the full Ninth Circuit, which was denied on July 8, 2011.

Cheetah Omni Litigation

On July 29, 2011, Cheetah Omni LLC filed a complaint for patent infringement in the United States District Court for the Eastern District of Texas against Alcatel-Lucent USA Inc., Alcatel-Lucent Holdings, Inc., Ciena Corporation, Ciena Communications, Inc., Fujitsu Network Communications, Inc., Tellabs, Inc., Tellabs Operations, Inc., Tellabs North America, Inc., Nokia Siemens Networks US LLC, Huawei Technologies USA, Inc. and Huawei Device USA, Inc. Finisar was not named as a defendant in the lawsuit. However, the named defendants or entities affiliated with them are Finisar customers. The complaint alleges that certain ROADM products of the named defendants infringe one or more of seven Cheetah Omni patents. With respect to two of the seven patents, the Company understands Cheetah Omni to be asserting infringement by the customer defendants' making, using, offering for sale, selling, and/or importing into the United States certain ROADM products that include a Finisar wavelength selective switch (WSS). Finisar has no specific information regarding whether the claims of infringement with respect to the remaining five asserted Cheetah Omni patents implicate any Finisar products.

To date, Finisar has received a request for indemnification from two customers with respect to the two patents mentioned above and may receive additional requests in the future. The Company is currently evaluating the request for indemnification. The Company also expects that the defendant customers will defend the lawsuit vigorously at least with respect to the claims that implicate any Finisar products. However, there can be no assurance that they will be successful in their defense and, if they are not successful with respect to the two patents mentioned above, Finisar may be liable to indemnify the accused customers for significant damages. Even if the defense is successful, the Company may incur substantial legal fees and other costs in defending and/or aiding in the defense of the lawsuit with respect to the two patents mentioned above. Further, the lawsuit could divert the efforts and attention of the Company's management and technical personnel, which could harm its business.

Securities Class Action

A securities class action lawsuit was filed on November 30, 2001 in the United States District Court for the Southern District of New York, purportedly on behalf of all persons who purchased the Company's common stock from November 17, 1999 through December 6, 2000. The complaint named as defendants the Company, Jerry S. Rawls, its Chairman of the Board and formerly its President and Chief Executive Officer, Frank H. Levinson, its former Chairman of the Board and Chief Technical Officer, Stephen K. Workman, its former Senior Vice President and Chief Financial Officer, and an investment banking firm that served as an underwriter for the Company's initial public offering in November 1999 and a secondary offering in April 2000. The complaint, as subsequently amended, alleges violations of Sections 11 and 15 of the Securities Act of 1933 and Sections 10(b) and 20(b) of the Securities Exchange Act of 1934, on the grounds that the prospectuses incorporated in the registration statements for the offerings failed to disclose, among other things, that (i) the underwriter had solicited and received excessive and undisclosed commissions from certain investors in exchange for which the underwriter allocated to those investors material portions of the shares of the Company's stock sold in the offerings and (ii) the underwriter had entered into agreements with customers whereby the underwriter agreed to allocate shares of the Company's stock sold in the offerings to those customers in exchange for which the customers agreed to purchase additional shares of the Company's stock in the after market at pre-determined prices. No specific damages are claimed. Similar allegations have been made in lawsuits relating to more than 300 other initial public offerings conducted in 1999 and 2000, which were consolidated for pretrial purposes. In October 2002, all claims against the individual defendants were dismissed without prejudice. On February 19, 2003, the Court denied defendants' motion to dismiss the complaint.

In February 2009, the parties reached an understanding regarding the principal elements of a settlement, subject to formal documentation and Court approval. Under the settlement, the underwriter defendants will pay a total of $486 million, and the issuer defendants and their insurers will pay a total of $100 million to settle all of the cases. On August 25, 2009, the Company funded approximately $327,000 with respect to its pro rata share of the issuers' contribution to the settlement and certain costs. This amount was accrued in the Company's consolidated financial statements during the first quarter of fiscal 2010. On October 2, 2009, the Court granted approval of the settlement and on November 19, 2009 the Court entered final judgment. The judgment has been appealed by certain individual class members.

Other

During the second quarter of fiscal 2012, the Company received a favorable arbitrator's decision in an intellectual property legal dispute unrelated to current or future quarters awarding the Company $7.4 million. As litigation related to the decision is ongoing, no amounts were recognized in the Company's consolidated financial statements as of, and for the three- and six-month periods ending, October 30, 2011.

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.