I can't find any infromation in our knowledge base about integrating with Okta; so I don't know that it's been done.
The only mention I find is in another post in the Community;
It still doesn't look to me like this has been tried.
-- Craig A.
We had a call with ptc and they told us to use PingFederate:
However, there may be drawbacks such as a user having to login multiple times. We have not had a chance to test the functionality yet, but were told that if PingFederate does not work, customization would be required.