Commitments and Contingencies	3 Months Ended
Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal and Regulatory Matters Korean Tax Audit In July 2016, we received an assessment from the tax authorities in Korea related to an ongoing tax audit of approximately $12 million. See Note 12. Income Taxes for additional information. Legal Proceedings On March 7, 2016, a putative class action lawsuit captioned Matthew Crandall v. PTC Inc. et al., No. 1:16-cv-10471, was filed against us and certain of our current and former officers and directors in the U.S. District Court for the District of Massachusetts, ostensibly on behalf of purchasers of our stock during the period November 24, 2011 through July 29, 2015. The lawsuit, which seeks unspecified damages, interest, attorneys’ fees and costs, alleges (among other things) that, during that period, PTC’s public disclosures concerning investigations by the U.S. Securities and Exchange Commission and the U.S. Department of Justice into U.S. Foreign Corrupt Practices Act matters in China (the "China Investigation") were false and/or misleading. The parties have agreed to settle this lawsuit for an amount that is not material to our results of operations and the associated liability was accrued in our fiscal 2016 results. The settlement is subject to execution and final court approval of definitive settlement documentations. We cannot predict the outcome of this action nor when it will be resolved. We are subject to various other legal proceedings and claims that arise in the ordinary course of business. We do not believe that resolving the legal proceedings and claims that we are currently subject to will have a material adverse impact on our financial condition, results of operations or cash flows. However, the results of legal proceedings cannot be predicted with certainty. Should any of these legal proceedings and claims be resolved against us, the operating results for a particular reporting period could be adversely affected. Accruals With respect to legal proceedings and claims, we record an accrual for a contingency when it is probable that a liability has been incurred and the amount of the loss can be reasonably estimated. For legal proceedings and claims for which the likelihood that a liability has been incurred is more than remote but less than probable, we estimate the range of possible outcomes. As of December 31, 2016, we had a legal proceedings and claims accrual of $2.5 million. Guarantees and Indemnification Obligations We enter into standard indemnification agreements in the ordinary course of our business. Pursuant to such agreements with our business partners or customers, we indemnify, hold harmless, and agree to reimburse the indemnified party for losses suffered or incurred by the indemnified party, generally in connection with patent, copyright or other intellectual property infringement claims by any third party with respect to our products, as well as claims relating to property damage or personal injury resulting from the performance of services by us or our subcontractors. The maximum potential amount of future payments we could be required to make under these indemnification agreements is unlimited. Historically, our costs to defend lawsuits or settle claims relating to such indemnity agreements have been minimal and we accordingly believe the estimated fair value of liabilities under these agreements is immaterial. We warrant that our software products will perform in all material respects in accordance with our standard published specifications in effect at the time of delivery of the licensed products for a specified period of time. Additionally, we generally warrant that our consulting services will be performed consistent with generally accepted industry standards. In most cases, liability for these warranties is capped. If necessary, we would provide for the estimated cost of product and service warranties based on specific warranty claims and claim history; however, we have not incurred significant cost under our product or services warranties. As a result, we believe the estimated fair value of these liabilities is immaterial.

Commitments and Contingencies

Legal and Regulatory Matters

Korean Tax Audit

In July 2016, we received an assessment from the tax authorities in Korea related to an ongoing tax audit of approximately $12 million. See Note 12. Income Taxes for additional information.

Legal Proceedings

On March 7, 2016, a putative class action lawsuit captioned Matthew Crandall v. PTC Inc. et al., No. 1:16-cv-10471, was filed against us and certain of our current and former officers and directors in the U.S. District Court for the District of Massachusetts, ostensibly on behalf of purchasers of our stock during the period November 24, 2011 through July 29, 2015. The lawsuit, which seeks unspecified damages, interest, attorneys’ fees and costs, alleges (among other things) that, during that period, PTC’s public disclosures concerning investigations by the U.S. Securities and Exchange Commission and the U.S. Department of Justice into U.S. Foreign Corrupt Practices Act matters in China (the "China Investigation") were false and/or misleading. The parties have agreed to settle this lawsuit for an amount that is not material to our results of operations and the associated liability was accrued in our fiscal 2016 results. The settlement is subject to execution and final court approval of definitive settlement documentations. We cannot predict the outcome of this action nor when it will be resolved.

We are subject to various other legal proceedings and claims that arise in the ordinary course of business. We do not believe that resolving the legal proceedings and claims that we are currently subject to will have a material adverse impact on our financial condition, results of operations or cash flows. However, the results of legal proceedings cannot be predicted with certainty. Should any of these legal proceedings and claims be resolved against us, the operating results for a particular reporting period could be adversely affected.

Accruals

With respect to legal proceedings and claims, we record an accrual for a contingency when it is probable that a liability has been incurred and the amount of the loss can be reasonably estimated. For legal proceedings and claims for which the likelihood that a liability has been incurred is more than remote but less than probable, we estimate the range of possible outcomes. As of December 31, 2016, we had a legal proceedings and claims accrual of $2.5 million.

Guarantees and Indemnification Obligations

We enter into standard indemnification agreements in the ordinary course of our business. Pursuant to such agreements with our business partners or customers, we indemnify, hold harmless, and agree to reimburse the indemnified party for losses suffered or incurred by the indemnified party, generally in connection with patent, copyright or other intellectual property infringement claims by any third party with respect to our products, as well as claims relating to property damage or personal injury resulting from the performance of services by us or our subcontractors. The maximum potential amount of future payments we could be required to make under these indemnification agreements is unlimited. Historically, our costs to defend lawsuits or settle claims relating to such indemnity agreements have been minimal and we accordingly believe the estimated fair value of liabilities under these agreements is immaterial.

We warrant that our software products will perform in all material respects in accordance with our standard published specifications in effect at the time of delivery of the licensed products for a specified period of time. Additionally, we generally warrant that our consulting services will be performed consistent with generally accepted industry standards. In most cases, liability for these warranties is capped. If necessary, we would provide for the estimated cost of product and service warranties based on specific warranty claims and claim history; however, we have not incurred significant cost under our product or services warranties. As a result, we believe the estimated fair value of these liabilities is immaterial.