Iridescence was widely used in Dutch glass in the 1920s and 30s, but I have come across similar items in France, too. The shape looks twenties to me, and the very thin quality looks Leerdam - but you'd really need to handle the piece to be sure. I'd need to see the straw colour in daylight, and see/feel the rim finish in fine detail. Meanwhile, Lobmeyr and Poschinger should not be excluded either...
Incidentally, neither Hoffmann nor Lobmeyr were glass makers. Hoffmann was a designer who also worked for Lobmeyr, and Lobmeyr is a retail outlet in Vienna who does its own designs. If you ever get to Vienna, climb to the shuggely third floor where they have a fantastic display of things they made.