 EMERYVILLE, Calif.--BUSINESS WIRE--Grocery Outlet Holding Corp. NASDAQ: GO Grocery Outlet or the Company, the leading extreme-value retailer in the United States offering quality, name-brand opportunistic products at prices generally 40 to 70 below those of conventional retailers, today announced the opening of its 400th store and newest location in Hailey, Idaho. Located at 615 N Main St. in Hailey, Idaho, just south of the Sun Valley ski resort and east of Boise, the newest Grocer 