An odd phrase usually used to disparage. Features might include:
not "selling out"
continually looking for the new direction and not just cranking out similar or derivative works
not pandering to the public/lowest common denominator
not pandering to or compromising for a sponsor
not following well-trodden paths
not employing hackneyed cliches
not going for the cheap yuks by lampooning the popular, simple and feeble
not over-dramatizing one's role.

Those would just be the teensiest start of a definition.