Just to suggest a place to start, I'd put forward Erik Hoglund in the 60's. I haven't seen a Hoglund piece like this, but, of the people who worked for Boda at the time, this decanter/bottle seems closer to Hoglund's work. However, I'd expect something to be scratched on the bottom, an "H" and some numbers, for example. What's on the label and what's does the quality of the glass look like (bubbles and striations, for example)?
David