How can you determine what methods your workplace is using to spy on you?

I work from home, and I'm pretty sure my employer is monitoring my computer constantly. Several times a day, a small button will briefly pop up in the lower right corner that indicates my location is being used. At other times, a small white window will flash across the screen and disappear (it's rather obnoxious because it slows my computer for a few seconds). I'm not worried about video monitoring because my camera is physically blocked, but I wonder what they're doing with the mic.