Less than two weeks after the announcement of its acquisition of U.S. health care company One Medical, Amazon is continuing its expansion with a US$1.7 billion offer for iRobot, the manufacturer of Roomba automated vacuum cleaners.Less than two weeks after the announcement of its acquisition of U.S. health care company One Medical, Amazon is continuing its expansion with a US$1.7 billion offer for iRobot, the manufacturer of Roomba automated vacuum cleaners.