Some of the past year's most notable documentary filmmakers join for The Hollywood Reporter's Documentary Oscar Roundtable. The filmmakers include Alex Gibney ('Going Clear: Scientology and the Prison of Belief'), Michael Moore ('Where to Invade Next?'), Liz Garbus ('What Happened, Miss Simone?'), Amy Berg ('Prophet's Prey', 'Janis: Little Girl Blue'), Chai Vserhelyi ('Meru'), and Kirby Dick ('The Hunting Ground').