Commitments and Contingencies	6 Months Ended
Apr. 30, 2012
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Ontario Grant Ciena was awarded a conditional grant from the Province of Ontario in June 2011. Under this strategic jobs investment fund grant, Ciena can receive up to an aggregate of C$25.0 million in funding for eligible costs relating to certain next-generation, coherent optical transport development initiatives over the period from November 1, 2010 to October 31, 2015. Ciena anticipates receiving disbursements, approximating C$5.0 million per fiscal year over the period above. Amounts received under the grant are subject to recoupment in the event that Ciena fails to achieve certain minimum investment, employment and project milestones. As of April 30, 2012, Ciena has recorded a C$8.3 million benefit to date as a reduction in research and development expenses, of which C$3.0 million was recorded in the first six months of fiscal 2012. Ciena believes it has complied with the conditions entitling it to this disbursement, of which C$5.0 million has been received. Foreign Tax Contingencies Ciena has received assessment notices from the Mexican tax authorities asserting deficiencies in payments between 2001 and 2005 related primarily to income taxes and import taxes and duties. Ciena has filed judicial petitions appealing these assessments. As of October 31, 2011 and April 30, 2012, Ciena had accrued liabilities of $1.4 million and $1.6 million related to these contingencies, which are reported as a component of other current accrued liabilities. As of April 30, 2012, Ciena estimates that it could be exposed to possible losses of up to $5.8 million, for which it has not accrued liabilities. Ciena has not accrued the additional income tax liabilities because it does not believe that such losses are probable. Ciena has not accrued the additional import taxes and duties because it does not believe the incurrence of such losses are probable. Ciena continues to evaluate the likelihood of probable and reasonably possible losses, if any, related to these assessments. As a result, future increases or decreases to accrued liabilities may be necessary and will be recorded in the period when such amounts are estimable and more likely than not (for income taxes) or probable (for non-income taxes). In addition to the matters described above, Ciena is subject to various tax liabilities arising in the ordinary course of business. Ciena does not expect that the ultimate settlement of these liabilities will have a material effect on its results of operations, financial position or cash flows. Litigation On July 29, 2011, Cheetah Omni LLC filed a complaint in the United States District Court for the Eastern District of Texas against Ciena and several other defendants, alleging, among other things, that certain of the parties' products infringe upon multiple U.S. Patents relating to certain reconfigurable optical add-drop multiplexer (ROADM) technologies. The complaint seeks injunctive relief and damages. On November 8, 2011, Ciena filed an answer and counterclaims to Cheetah Omni's amended complaint. Ciena believes that it has valid defenses to the lawsuit and intends to defend it vigorously. On May 29, 2008, Graywire, LLC filed a complaint in the United States District Court for the Northern District of Georgia against Ciena and four other defendants, alleging, among other things, that certain of the parties' products infringe U.S. Patent 6,542,673 (the “'673 Patent”), relating to an identifier system and components for optical assemblies. The complaint seeks injunctive relief and damages. Ciena filed an answer to the complaint and counterclaims against Graywire on April 17, 2009. On April 27, 2009, Ciena and certain other defendants filed an application for inter partes reexamination of the '673 Patent with the U.S. Patent and Trademark Office (the “PTO”). On the same date, Ciena and the other defendants filed a motion to stay the case pending reexamination of all of the patents-in-suit. On July 17, 2009, the district court granted the defendants' motion to stay the case. On July 23, 2009, the PTO granted the defendants' application for reexamination with respect to certain claims of the '673 Patent and, on December 17, 2010, the PTO confirmed the validity of some claims and rejected the validity of other claims. On February 28, 2011, Ciena and the other defendants filed an appeal with respect to certain aspects of the PTO's determination. Separately, on March 17, 2011, the PTO granted a third party application for ex parte reexamination with respect to certain claims of the '673 Patent and, on September 2, 2011, the PTO issued a non-final rejection of the validity of those claims. On December 14, 2011, the PTO issued a Notice of Intent to Issue a Reexamination Certificate in the ex parte reexamination. Ciena believes that it has valid defenses to the lawsuit and intends to defend it vigorously in the event the stay of the case is lifted. As a result of its June 2002 acquisition of ONI Systems Corp., Ciena became a defendant in a securities class action lawsuit filed in the United States District Court for the Southern District of New York in August 2001. The cause of action and history of the proceedings are more fully described in Ciena's Annual Report on Form 10-K for fiscal 2011 filed with the SEC on December 22, 2011. On January 9, 2012, the final appellant in this securities class action lawsuit withdrew and dismissed his appeal with prejudice in accordance with the terms of the settlement agreement. Ciena was not required to pay any amount toward the settlement or to make any other payments to plaintiffs in connection with the resolution of this matter. In addition to the matters described above, Ciena is subject to various legal proceedings, claims and litigation arising in the ordinary course of business. Ciena does not expect that the ultimate costs to resolve these matters will have a material effect on its results of operations, financial position or cash flows. Operating Lease Commitments Ciena entered into a lease agreement dated November 3, 2011, with W2007 RDG Realty, L.L.C. relating to office space for its new corporate headquarters in Hanover, Maryland, consisting of an agreed-upon rentable area of approximately 154,100 square feet. The future minimal rental commitments to be paid over the 15-year lease term are approximately $64.9 million.

COMMITMENTS AND CONTINGENCIES

Ontario Grant

Ciena was awarded a conditional grant from the Province of Ontario in June 2011. Under this strategic jobs investment fund grant, Ciena can receive up to an aggregate of C$25.0 million in funding for eligible costs relating to certain next-generation, coherent optical transport development initiatives over the period from November 1, 2010 to October 31, 2015. Ciena anticipates receiving disbursements, approximating C$5.0 million per fiscal year over the period above. Amounts received under the grant are subject to recoupment in the event that Ciena fails to achieve certain minimum investment, employment and project milestones. As of April 30, 2012, Ciena has recorded a C$8.3 million benefit to date as a reduction in research and development expenses, of which C$3.0 million was recorded in the first six months of fiscal 2012. Ciena believes it has complied with the conditions entitling it to this disbursement, of which C$5.0 million has been received.

Foreign Tax Contingencies

Ciena has received assessment notices from the Mexican tax authorities asserting deficiencies in payments between 2001 and 2005 related primarily to income taxes and import taxes and duties. Ciena has filed judicial petitions appealing these assessments. As of October 31, 2011 and April 30, 2012, Ciena had accrued liabilities of $1.4 million and $1.6 million related to these contingencies, which are reported as a component of other current accrued liabilities. As of April 30, 2012, Ciena estimates that it could be exposed to possible losses of up to $5.8 million, for which it has not accrued liabilities. Ciena has not accrued the additional income tax liabilities because it does not believe that such losses are probable. Ciena has not accrued the additional import taxes and duties because it does not believe the incurrence of such losses are probable. Ciena continues to evaluate the likelihood of probable and reasonably possible losses, if any, related to these assessments. As a result, future increases or decreases to accrued liabilities may be necessary and will be recorded in the period when such amounts are estimable and more likely than not (for income taxes) or probable (for non-income taxes).

In addition to the matters described above, Ciena is subject to various tax liabilities arising in the ordinary course of business. Ciena does not expect that the ultimate settlement of these liabilities will have a material effect on its results of operations, financial position or cash flows.

Litigation

On July 29, 2011, Cheetah Omni LLC filed a complaint in the United States District Court for the Eastern District of Texas against Ciena and several other defendants, alleging, among other things, that certain of the parties' products infringe upon multiple U.S. Patents relating to certain reconfigurable optical add-drop multiplexer (ROADM) technologies. The complaint seeks injunctive relief and damages. On November 8, 2011, Ciena filed an answer and counterclaims to Cheetah Omni's amended complaint. Ciena believes that it has valid defenses to the lawsuit and intends to defend it vigorously.

On May 29, 2008, Graywire, LLC filed a complaint in the United States District Court for the Northern District of Georgia against Ciena and four other defendants, alleging, among other things, that certain of the parties' products infringe U.S. Patent 6,542,673 (the “'673 Patent”), relating to an identifier system and components for optical assemblies. The complaint seeks injunctive relief and damages. Ciena filed an answer to the complaint and counterclaims against Graywire on April 17, 2009. On April 27, 2009, Ciena and certain other defendants filed an application for inter partes reexamination of the '673 Patent with the U.S. Patent and Trademark Office (the “PTO”). On the same date, Ciena and the other defendants filed a motion to stay the case pending reexamination of all of the patents-in-suit. On July 17, 2009, the district court granted the defendants' motion to stay the case. On July 23, 2009, the PTO granted the defendants' application for reexamination with respect to certain claims of the '673 Patent and, on December 17, 2010, the PTO confirmed the validity of some claims and rejected the validity of other claims. On February 28, 2011, Ciena and the other defendants filed an appeal with respect to certain aspects of the PTO's determination. Separately, on March 17, 2011, the PTO granted a third party application for ex parte reexamination with respect to certain claims of the '673 Patent and, on September 2, 2011, the PTO issued a non-final rejection of the validity of those claims. On December 14, 2011, the PTO issued a Notice of Intent to Issue a Reexamination Certificate in the ex parte reexamination. Ciena believes that it has valid defenses to the lawsuit and intends to defend it vigorously in the event the stay of the case is lifted.

As a result of its June 2002 acquisition of ONI Systems Corp., Ciena became a defendant in a securities class action lawsuit filed in the United States District Court for the Southern District of New York in August 2001. The cause of action and history of the proceedings are more fully described in Ciena's Annual Report on Form 10-K for fiscal 2011 filed with the SEC on December 22, 2011. On January 9, 2012, the final appellant in this securities class action lawsuit withdrew and dismissed his appeal with prejudice in accordance with the terms of the settlement agreement. Ciena was not required to pay any amount toward the settlement or to make any other payments to plaintiffs in connection with the resolution of this matter.

In addition to the matters described above, Ciena is subject to various legal proceedings, claims and litigation arising in the ordinary course of business. Ciena does not expect that the ultimate costs to resolve these matters will have a material effect on its results of operations, financial position or cash flows.

Operating Lease Commitments

Ciena entered into a lease agreement dated November 3, 2011, with W2007 RDG Realty, L.L.C. relating to office space for its new corporate headquarters in Hanover, Maryland, consisting of an agreed-upon rentable area of approximately 154,100 square feet. The future minimal rental commitments to be paid over the 15-year lease term are approximately $64.9 million.