My shower door had a small 'separation' at the bottom where it is hinged to the side-panel. Throught this small separation, and over a few years, the water that came through it leaked to the drywall ceiling below, thus, 'creating a job' for me.
My point is, if you're only fairly sure that the leak is through the shower door, and not CERTAIN, maybe the next time you take a shower, you should consider 'posting' somone outside the door to see if there are any leaks. Only I use my shower; my wife has her own full-bath. I actually laid a piece of facial tissue on the floor just below this separation while I took a shower to see if that's where the water was coming from. Lo and behold, when I finished my shower, the tissue was wet enough to lead me to my conclusion!
Believe it or not, the separation was a 'natural' one. In other words, it wasn't from wear-and-tear on the door. It was just poor construction. (I didn't buy or install it; I inherited it from the previous owners.) I manufactured a sort of 'shield' with some duct tape, and 'hung' it above the separation INSIDE the shower. Henceforth, no more water splashing through the separation. Oh, my shower is a stall only; NOT a shower/bathtub. (I have a 3/4 bathroom; NOT a full bathroom.) Anyway, I thought I let you know that you ought to try and CONFIRM your 'leak'. I'll tell ya, I HATE any project where water is involved! I just put in a Water Inlet Valve on my GE Dishwasher a week ago. I still have the bottom cover off because I don't trust myself that 1) there are no leaks from the new valve, and 2) I didn't create any new/other leaks in the process! I've only gone through 3 washing cycles so far, and won't put the cover on until I do a few more. That's how much I trust my own plumbing AND how much I love working on water-related problems.