This is one of those questions that have 100 different answers. The first place to look for the answer is in the employment agreement the employee signed (if there is one). Also review the employee handbook for any notes.
Next look at how the IP was developed. Did the employee use any hardware, software, or anything else owned by company while developing IP? This includes any existing IP owned by the company that the employee may have built on. Write software on the boss's computer or on the boss's time then it belongs to the boss.
Next, did employee discuss IP with any coworkers on company time? This is usually not a big deal in the real world but something avoid if at all possible.
If you have those bases covered then contact an IP lawyer and get get a provisional patent. The lawyer will also review anything that is important for your jurisdiction.
This is one of those questions that have 100 different answers. The first place to look for the answer is in the employment agreement the employee signed (if there is one). Also review the employee handbook for any notes.
Next look at how the IP was developed. Did the employee use any hardware, software, or anything else owned by company while developing IP? This includes any existing IP owned by the company that the employee may have built on. Write software on the boss's computer or on the boss's time then it belongs to the boss.
Next, did employee discuss IP with any coworkers on company time? This is usually not a big deal in the real world but something avoid if at all possible.
If you have those bases covered then contact an IP lawyer and get get a provisional patent. The lawyer will also review anything that is important for your jurisdiction.
Good luck.