Doug Hamilton’s documentary about the theatrical adaptation of Green Day’s acclaimed album American Idiot tries to gin up some tension by proposing a divide between rock and legitimate theater that hasn’t really existed for 20 years. Yet the interview sequences quickly turn into an endless circle jerk as stage director Michael Mayer soaps up rocker Billie Joe Armstrong, actors gush over what American Idiot meant to them, and Armstrong talks up their work, expressing his excitement and professional respect. Home-video footage reveals that Armstrong was a closet show-tunes fan as a tyke, and the docuentary ends on an amusing note when he joins the show for a week in a supporting role. Like the show’s producers, Hamilton can’t go too far wrong because American Idiot is such a killer collection of songs; whether we’re hearing the original 2002 recording, live footage of Green Day performing it for a UK stadium crowd in 2005, or the cast tearing through the songs in chorus, the music propels the movie.