Contingencies	6 Months Ended
Apr. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Contingencies	Contingencies Legal Proceedings The Company is subject to routine legal proceedings, as well as demands, claims and threatened litigation that arise in the normal course of its business. The ultimate outcome of any litigation is uncertain and unfavorable outcomes could have a negative impact on the Company’s results of operations and financial condition. The Company reviews the status of each significant matter and assesses its potential financial exposure. If the potential loss from any claim or legal proceeding is considered probable and the amount is estimable, the Company accrues a liability for the estimated loss. The Company has determined that, except as set forth below, no disclosure of estimated loss is required for a claim against the Company because: (1) there is not a reasonable possibility that a loss exceeding amounts already recognized (if any) may be incurred with respect to such claim; (2) a reasonably possible loss or range of loss cannot be estimated; or (3) such estimate is immaterial. Mentor Patent Litigation The Company is engaged in complex patent litigation with Mentor Graphics Corporation (Mentor) involving several actions in different forums. The Company succeeded to the litigation when it acquired Emulation & Verification Engineering S.A. (EVE) on October 4, 2012. At the time of the acquisition, EVE and EVE-USA, Inc. (collectively, the EVE Parties) had been defendants in three patent infringement lawsuits filed by Mentor. Each lawsuit as well as subsequent lawsuits are further described below. Background As mentioned above, at the time of the acquisition, the EVE Parties had been defendants in three patent infringement lawsuits filed by Mentor. Mentor filed suit against the EVE Parties in federal district court in the District of Oregon on August 16, 2010 alleging that EVE’s ZeBu products infringed Mentor’s United States Patent No. 6,876,962. Mentor filed an additional suit in federal district court in the District of Oregon on August 17, 2012 alleging that EVE’s ZeBu products infringed Mentor’s United States Patent No. 6,947,882. Both cases sought damages and a permanent injunction. On September 27, 2012, the Company and the EVE Parties filed an action for declaratory relief against Mentor in federal district court in the Northern District of California, seeking a determination that Mentor’s United States Patents Nos. 6,009,531, 5,649,176, and 6,240,376, which were the subject of a patent infringement lawsuit filed by Mentor against EVE in 2006 and settled in the same year, are invalid and not infringed by EVE’s products. Mentor asserted patent infringement counterclaims in this action based on the same three patents and sought damages and a permanent injunction. In April 2013, this action was transferred to the federal district court in Oregon and consolidated with the two Mentor lawsuits in that district (the Oregon Action), as further described below. The Oregon Action After transfer of the Company’s declaratory relief action to Oregon and consolidation of that action with Mentor’s 2010 and 2012 lawsuits, the Company asserted patent infringement counterclaims against Mentor based on the Company’s United States Patents Nos. 6,132,109 and 7,069,526, seeking damages and a permanent injunction. After pre-trial summary judgment rulings in favor of both sides, the only patent remaining at issue in the Oregon Action was Mentor's ‘376 patent. The Oregon Action went to trial on the remaining Mentor patent, and a jury reached a verdict on October 10, 2014 finding that certain features of the ZeBu products infringed the ‘376 patent and assessing damages of approximately $36 million. On March 12, 2015, the court entered an injunction prohibiting certain sales activities relating to the features found by the jury to infringe. The Company released a new version of ZeBu software that does not include such features. The Company accrued an immaterial amount as a loss contingency in the quarter ended October 31, 2015. Both parties appealed from the court’s judgment following the jury verdict. The Federal Circuit heard the parties’ respective appeals and issued a decision on March 16, 2017. The panel affirmed the jury verdict and damages award on Mentor’s ‘376 patent and reversed the district court’s dismissal of Mentor’s ‘176, ‘531 and ‘882 patents and the Company’s ‘109 patent. Proceedings on these patents will resume in the federal district court in Oregon, including trial of alleged supplemental damages on and willful infringement of the ‘376 patent. On May 1, 2017, the Company petitioned for rehearing by all judges currently sitting on the Federal Circuit. On May 9, 2017, the Federal Circuit invited Mentor to respond to the petition on or before May 23, 2017. Due to the affirmation of the verdict by the Federal Circuit, the Company has accrued an aggregate amount of $39.0 million as a loss contingency, which is the amount estimated to be the probable loss. The associated charge has been recorded in general and administrative expenses in the income statements for the three and six months ended April 30, 2017. The California Action On December 21, 2012, the Company filed an action for patent infringement against Mentor in federal district court in the Northern District of California, alleging that Mentor’s Veloce products infringe the Company’s United States Patents Nos. 5,748,488, 5,530,841, 5,680,318 and 6,836,420 (the California Action). This case sought damages and a permanent injunction. The court stayed the action as to the ‘420 patent pending the U.S. Patent and Trademark Office's inter partes review of that patent and appeals from that proceeding. On January 20, 2015, the court granted Mentor's motion for summary judgment on the ‘488, ‘841, and ‘318 patents, finding that such patents were invalid. The Company appealed the court's ruling and on October 17, 2016, the Federal Circuit affirmed the district court’s decision. The Company is currently seeking review of the Federal Circuit’s ruling in the U.S. Supreme Court. PTO Proceedings On September 26, 2012, the Company filed two inter partes review requests with the U.S. Patent and Trademark Office (the PTO) challenging the validity of Mentor’s ‘376 and ‘882 patents. The PTO granted review of the ‘376 patent and denied review of the ‘882 patent. On February 19, 2014, the PTO issued its final decision in the review of the ‘376 patent, finding some of the challenged claims invalid and some of the challenged claims valid. On April 22, 2014, the Company appealed to the Federal Circuit from the PTO’s decision finding certain claims valid. Mentor filed a cross-appeal on May 2, 2014 from the PTO's decision finding certain claims invalid. On February 10, 2016, the Federal Circuit affirmed the PTO's decision in all respects. On December 21, 2013, Mentor filed an inter partes review request with the PTO challenging the validity of the Company’s ‘420 patent. On June 11, 2015, the PTO issued its final decision in the review, finding all of the challenged claims invalid. On August 12, 2015, the Company appealed to the Federal Circuit from the PTO's decision. On October 11, 2016, the Federal Circuit affirmed the PTO’s decision. On September 30, 2016, the Company filed a petition requesting ex parte reexamination of all of the claims of the ‘376 patent asserted in the Oregon Action. Mentor objected on procedural grounds. On November 8, 2016, the PTO instituted reexamination of the ‘376 patent. On December 15, 2016, the PTO vacated its decision to institute reexamination based upon Mentor’s procedural objection. The Company thereafter filed a renewed request for ex parte reexamination of only Claims 24, 26 and 27 of the patent, which was granted by the PTO in February 2017. On May 2, 2017, the Company also sued the PTO in federal district court in the Eastern District of Virginia, challenging the PTO’s decision not to institute reexamination of Claims 1 and 28. The ex parte reexamination and the lawsuit are ongoing. While the Company intends to defend all of the above matters vigorously, the ultimate outcome of any litigation, including the litigation with Mentor, is uncertain and may have an adverse outcome resulting in losses beyond recorded amounts. In the event of an unfavorable final outcome, there exists the possibility of a material adverse impact on the Company's consolidated financial statements for the period in which the effects become reasonably estimable. Non-Income Based Taxes The Company undergoes examination from time to time by U.S. and foreign authorities for non-income based taxes, such as sales, use and value-added taxes. The Company is currently under examination by tax authorities in certain jurisdictions. If the potential loss from such examinations is considered probable and the amount or the range of loss could be estimated, the Company would accrue a liability for the estimated expense.

Contingencies

Legal Proceedings

The Company is subject to routine legal proceedings, as well as demands, claims and threatened litigation that arise in the normal course of its business. The ultimate outcome of any litigation is uncertain and unfavorable outcomes could have a negative impact on the Company’s results of operations and financial condition. The Company reviews the status of each significant matter and assesses its potential financial exposure. If the potential loss from any claim or legal proceeding is considered probable and the amount is estimable, the Company accrues a liability for the estimated loss. The Company has determined that, except as set forth below, no disclosure of estimated loss is required for a claim against the Company because: (1) there is not a reasonable possibility that a loss exceeding amounts already recognized (if any) may be incurred with respect to such claim; (2) a reasonably possible loss or range of loss cannot be estimated; or (3) such estimate is immaterial.

Mentor Patent Litigation

The Company is engaged in complex patent litigation with Mentor Graphics Corporation (Mentor) involving several actions in different forums. The Company succeeded to the litigation when it acquired Emulation & Verification Engineering S.A. (EVE) on October 4, 2012. At the time of the acquisition, EVE and EVE-USA, Inc. (collectively, the EVE Parties) had been defendants in three patent infringement lawsuits filed by Mentor. Each lawsuit as well as subsequent lawsuits are further described below.

Background

As mentioned above, at the time of the acquisition, the EVE Parties had been defendants in three patent infringement lawsuits filed by Mentor. Mentor filed suit against the EVE Parties in federal district court in the District of Oregon on August 16, 2010 alleging that EVE’s ZeBu products infringed Mentor’s United States Patent No. 6,876,962. Mentor filed an additional suit in federal district court in the District of Oregon on August 17, 2012 alleging that EVE’s ZeBu products infringed Mentor’s United States Patent No. 6,947,882. Both cases sought damages and a permanent injunction.

On September 27, 2012, the Company and the EVE Parties filed an action for declaratory relief against Mentor in federal district court in the Northern District of California, seeking a determination that Mentor’s United States Patents Nos. 6,009,531, 5,649,176, and 6,240,376, which were the subject of a patent infringement lawsuit filed by Mentor against EVE in 2006 and settled in the same year, are invalid and not infringed by EVE’s products. Mentor asserted patent infringement counterclaims in this action based on the same three patents and sought damages and a permanent injunction. In April 2013, this action was transferred to the federal district court in Oregon and consolidated with the two Mentor lawsuits in that district (the Oregon Action), as further described below.

The Oregon Action

After transfer of the Company’s declaratory relief action to Oregon and consolidation of that action with Mentor’s 2010 and 2012 lawsuits, the Company asserted patent infringement counterclaims against Mentor based on the Company’s United States Patents Nos. 6,132,109 and 7,069,526, seeking damages and a permanent injunction. After pre-trial summary judgment rulings in favor of both sides, the only patent remaining at issue in the Oregon Action was Mentor's ‘376 patent.

The Oregon Action went to trial on the remaining Mentor patent, and a jury reached a verdict on October 10, 2014 finding that certain features of the ZeBu products infringed the ‘376 patent and assessing damages of approximately $36 million. On March 12, 2015, the court entered an injunction prohibiting certain sales activities relating to the features found by the jury to infringe. The Company released a new version of ZeBu software that does not include such features. The Company accrued an immaterial amount as a loss contingency in the quarter ended October 31, 2015. Both parties appealed from the court’s judgment following the jury verdict.

The Federal Circuit heard the parties’ respective appeals and issued a decision on March 16, 2017. The panel affirmed the jury verdict and damages award on Mentor’s ‘376 patent and reversed the district court’s dismissal of Mentor’s ‘176, ‘531 and ‘882 patents and the Company’s ‘109 patent. Proceedings on these patents will resume in the federal district court in Oregon, including trial of alleged supplemental damages on and willful infringement of the ‘376 patent. On May 1, 2017, the Company petitioned for rehearing by all judges currently sitting on the Federal Circuit. On May 9, 2017, the Federal Circuit invited Mentor to respond to the petition on or before May 23, 2017.

Due to the affirmation of the verdict by the Federal Circuit, the Company has accrued an aggregate amount of $39.0 million as a loss contingency, which is the amount estimated to be the probable loss. The associated charge has been recorded in general and administrative expenses in the income statements for the three and six months ended April 30, 2017.

The California Action

On December 21, 2012, the Company filed an action for patent infringement against Mentor in federal district court in the Northern District of California, alleging that Mentor’s Veloce products infringe the Company’s United States Patents Nos. 5,748,488, 5,530,841, 5,680,318 and 6,836,420 (the California Action). This case sought damages and a permanent injunction. The court stayed the action as to the ‘420 patent pending the U.S. Patent and Trademark Office's inter partes review of that patent and appeals from that proceeding. On January 20, 2015, the court granted Mentor's motion for summary judgment on the ‘488, ‘841, and ‘318 patents, finding that such patents were invalid. The Company appealed the court's ruling and on October 17, 2016, the Federal Circuit affirmed the district court’s decision. The Company is currently seeking review of the Federal Circuit’s ruling in the U.S. Supreme Court.

PTO Proceedings

On September 26, 2012, the Company filed two inter partes review requests with the U.S. Patent and Trademark Office (the PTO) challenging the validity of Mentor’s ‘376 and ‘882 patents. The PTO granted review of the ‘376 patent and denied review of the ‘882 patent. On February 19, 2014, the PTO issued its final decision in the review of the ‘376 patent, finding some of the challenged claims invalid and some of the challenged claims valid. On April 22, 2014, the Company appealed to the Federal Circuit from the PTO’s decision finding certain claims valid. Mentor filed a cross-appeal on May 2, 2014 from the PTO's decision finding certain claims invalid. On February 10, 2016, the Federal Circuit affirmed the PTO's decision in all respects.

On December 21, 2013, Mentor filed an inter partes review request with the PTO challenging the validity of the Company’s ‘420 patent. On June 11, 2015, the PTO issued its final decision in the review, finding all of the challenged claims invalid. On August 12, 2015, the Company appealed to the Federal Circuit from the PTO's decision. On October 11, 2016, the Federal Circuit affirmed the PTO’s decision.

On September 30, 2016, the Company filed a petition requesting ex parte reexamination of all of the claims of the ‘376 patent asserted in the Oregon Action. Mentor objected on procedural grounds. On November 8, 2016, the PTO instituted reexamination of the ‘376 patent. On December 15, 2016, the PTO vacated its decision to institute reexamination based upon Mentor’s procedural objection. The Company thereafter filed a renewed request for ex parte reexamination of only Claims 24, 26 and 27 of the patent, which was granted by the PTO in February 2017. On May 2, 2017, the Company also sued the PTO in federal district court in the Eastern District of Virginia, challenging the PTO’s decision not to institute reexamination of Claims 1 and 28. The ex parte reexamination and the lawsuit are ongoing.

While the Company intends to defend all of the above matters vigorously, the ultimate outcome of any litigation, including the litigation with Mentor, is uncertain and may have an adverse outcome resulting in losses beyond recorded amounts. In the event of an unfavorable final outcome, there exists the possibility of a material adverse impact on the Company's consolidated financial statements for the period in which the effects become reasonably estimable.

Non-Income Based Taxes

The Company undergoes examination from time to time by U.S. and foreign authorities for non-income based taxes, such as sales, use and value-added taxes. The Company is currently under examination by tax authorities in certain jurisdictions. If the potential loss from such examinations is considered probable and the amount or the range of loss could be estimated, the Company would accrue a liability for the estimated expense.