Document and Entity Information - USD ($)
12 Months Ended
Sep. 30, 2019
Nov. 15, 2019
Apr. 01, 2019
Cover page.      
Entity Registrant Name PTC Inc.    
Document Type 10-K    
Document Annual Report true    
Document Transition Report false    
Document Period End Date Sep. 30, 2019    
Current Fiscal Year End Date --09-30    
Document Fiscal Year Focus 2019    
Document Fiscal Period Focus FY    
Entity Incorporation, State or Country Code MA    
Entity Tax Identification Number 04-2866152    
Title of 12(b) Security Common Stock, $.01 par value per share    
Trading Symbol  PTC    
Security Exchange Name NASDAQ    
Entity File Number 0-18059    
Amendment Flag false    
Entity Central Index Key 0000857005    
Entity Filer Category Large Accelerated Filer    
Entity Small Business false    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Shell Company false    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Address, Address Line One 121 Seaport Boulevard    
Entity Address, City or Town Boston    
Entity Address, State or Province MA    
Entity Address, Postal Zip Code 02210    
City Area Code 781    
Local Phone Number 370-5000    
Entity Public Float     $ 10,784,576,792
Entity Common Stock, Shares Outstanding   115,492,735  
Entity Emerging Growth Company false    
Documents Incorporated by Reference
Portions of the definitive Proxy Statement in connection with the 2020 Annual Meeting of Stockholders (2020 Proxy Statement) are incorporated by reference into Part III.