Commitments and Contingencies	9 Months Ended
Oct. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Indemnifications Our license and services agreements generally include a limited indemnification provision for claims from third parties relating to our intellectual property (IP). The indemnification is generally limited to the amount paid by the customer, a multiple of the amount paid by the customer, or a set cap. As of October 31, 2015, we were not aware of any material liabilities arising from these indemnification obligations. Legal Proceedings From time to time we are involved in various disputes and litigation matters that arise in the ordinary course of business. These include disputes and lawsuits relating to IP rights, contracts, distributorships, and employee relations matters. Periodically, we review the status of various disputes and litigation matters and assess our potential exposure. When we consider the potential loss from any dispute or legal matter probable and the amount or the range of loss can be estimated, we will accrue a liability for the estimated loss. Legal proceedings are subject to uncertainties, and the outcomes are difficult to predict. Because of such uncertainties, we base accruals on the best information available at the time. As additional information becomes available, we reassess the potential liability related to pending claims and litigation matters and may revise estimates. We believe that the outcome of current litigation, individually and in the aggregate, will not have a material effect on our results of operations. In some instances, we are unable to reasonably estimate any potential loss or range of loss. The nature and progression of litigation can make it difficult to predict the impact a particular lawsuit will have. There are many reasons why we cannot make these assessments, including, among others, one or more of the following: a proceeding being in its early stages; damages sought that are unspecific, unsupportable, unexplained or uncertain; discovery not having been started or being incomplete; the complexity of the facts that are in dispute; the difficulty of assessing novel claims; the parties not having engaged in any meaningful settlement discussions; the possibility that other parties may share in any ultimate liability; and/or the often slow pace of litigation. In December 2012, Synopsys, Inc. (Synopsys) filed a lawsuit claiming patent infringement against us in federal district court in the Northern District of California, alleging that our Veloce^® family of products infringed four Synopsys U.S. patents. In January 2015, the court issued a summary judgment order in our favor invalidating all asserted claims of three of the Synopsys patents. In June 2015, the U.S. Patent Trademark Office ruled that claims of the remaining patent asserted against us by Synopsys are unpatentable. This case is no longer on the court’s docket for trial. Synopsys has appealed the decision by the district court. In May 2013, Synopsys also filed a claim against us in federal district court in Oregon, similarly alleging that our Veloce family of products infringed on two additional Synopsys U.S. patents. These claims have been dismissed. We believe these lawsuits were filed in response to patent lawsuits we filed in 2010 and 2012 against Emulation and Verification Engineering S.A. and EVE-USA, Inc. (together EVE), which Synopsys acquired in October 2012. On October 10, 2014, the jury in our patent lawsuit filed in the federal district court for the District of Oregon found that one of our patents - U.S. Patent No. 6,240,376 - was directly and indirectly infringed by EVE and Synopsys. As part of the verdict, the jury awarded us damages of approximately $36,000 as well as certain royalties. As of October 31, 2015, nothing has been included in our financial results for this award. Synopsys has filed an appeal. On March 12, 2015, the Oregon court granted our request for a permanent injunction against future sales of Synopsys emulators containing infringing technology. In December 2010, we filed a patent lawsuit against EVE in Tokyo district court, which seeks compensatory damages and an injunction against the sale of EVE emulation products. The technical trial for the Japanese litigation was held in October 2014. In May 2015, the court issued a preliminary verdict of non-infringement. We have appealed that verdict. We do not have sufficient information upon which to determine that a loss in connection with these matters is probable, reasonably possible, or estimable, and thus no liability has been established nor has a range of loss been disclosed.

Commitments and Contingencies

Indemnifications

Our license and services agreements generally include a limited indemnification provision for claims from third parties relating to our intellectual property (IP). The indemnification is generally limited to the amount paid by the customer, a multiple of the amount paid by the customer, or a set cap. As of October 31, 2015, we were not aware of any material liabilities arising from these indemnification obligations.

Legal Proceedings

From time to time we are involved in various disputes and litigation matters that arise in the ordinary course of business. These include disputes and lawsuits relating to IP rights, contracts, distributorships, and employee relations matters. Periodically, we review the status of various disputes and litigation matters and assess our potential exposure. When we consider the potential loss from any dispute or legal matter probable and the amount or the range of loss can be estimated, we will accrue a liability for the estimated loss. Legal proceedings are subject to uncertainties, and the outcomes are difficult to predict. Because of such uncertainties, we base accruals on the best information available at the time. As additional information becomes available, we reassess the potential liability related to pending claims and litigation matters and may revise estimates. We believe that the outcome of current litigation, individually and in the aggregate, will not have a material effect on our results of operations.

In some instances, we are unable to reasonably estimate any potential loss or range of loss. The nature and progression of litigation can make it difficult to predict the impact a particular lawsuit will have. There are many reasons why we cannot make these assessments, including, among others, one or more of the following: a proceeding being in its early stages; damages sought that are unspecific, unsupportable, unexplained or uncertain; discovery not having been started or being incomplete; the complexity of the facts that are in dispute; the difficulty of assessing novel claims; the parties not having engaged in any meaningful settlement discussions; the possibility that other parties may share in any ultimate liability; and/or the often slow pace of litigation.

In December 2012, Synopsys, Inc. (Synopsys) filed a lawsuit claiming patent infringement against us in federal district court in the Northern District of California, alleging that our Veloce^® family of products infringed four Synopsys U.S. patents. In January 2015, the court issued a summary judgment order in our favor invalidating all asserted claims of three of the Synopsys patents. In June 2015, the U.S. Patent Trademark Office ruled that claims of the remaining patent asserted against us by Synopsys are unpatentable. This case is no longer on the court’s docket for trial. Synopsys has appealed the decision by the district court.

In May 2013, Synopsys also filed a claim against us in federal district court in Oregon, similarly alleging that our Veloce family of products infringed on two additional Synopsys U.S. patents. These claims have been dismissed.

We believe these lawsuits were filed in response to patent lawsuits we filed in 2010 and 2012 against Emulation and Verification Engineering S.A. and EVE-USA, Inc. (together EVE), which Synopsys acquired in October 2012.

On October 10, 2014, the jury in our patent lawsuit filed in the federal district court for the District of Oregon found that one of our patents - U.S. Patent No. 6,240,376 - was directly and indirectly infringed by EVE and Synopsys. As part of the verdict, the jury awarded us damages of approximately $36,000 as well as certain royalties. As of October 31, 2015, nothing has been included in our financial results for this award. Synopsys has filed an appeal.

On March 12, 2015, the Oregon court granted our request for a permanent injunction against future sales of Synopsys emulators containing infringing technology.

In December 2010, we filed a patent lawsuit against EVE in Tokyo district court, which seeks compensatory damages and an injunction against the sale of EVE emulation products. The technical trial for the Japanese litigation was held in October 2014. In May 2015, the court issued a preliminary verdict of non-infringement. We have appealed that verdict.

We do not have sufficient information upon which to determine that a loss in connection with these matters is probable, reasonably possible, or estimable, and thus no liability has been established nor has a range of loss been disclosed.