What was the name of that movie?

Last year I watched this movie about a young man who would break into people's homes and spy on them. Then, one couple actually discovers their intruder, and they keep him hostage. For the life of me I can't remember the name of this flick--and it's driving me crazy! I want to say it was a semi-thriller type movie, but there wasn't any blood and guts. Can anyone help me--please?!