Shares of iRobot Corp. in Bedford fell sharply Wednesday after the company said it expects to lose money in its fourth quarter and that it is cutting 80 jobs, or 13 percent of its workforce.

Of the jobs lost, 40 are in Bedford and another 30 are the result of iRobot’s decision to close an office in North Carolina that worked on the Sea­glider, an underwater robot used by oceanographers as well as the Navy to collect data. IRobot will stop commercial production of the product.