When I started billing from home, I just took a basic common sense approach... purchased a laptop only I use and have access to, I had excellent protection installed on it, and made sure to "lock" areas of it that needed locking, if necessary. I explained to the store I purchased the laptop from what my needs were, and they suggested one that was most reasonable in price, and has more than enough memory for what I need.
Honestly, with most of what I do being cloud based, I don't worry much about PHI being compromised. I rarely if ever print anything off, and if I do, it gets locked up, until I shred it.