Both scientists and their ideas have often been described as "heretical," "before their time," or "rebellious" against a status quo. However, it is impossible to attach a philosophically and historically precise definition to these terms: since Thomas Kuhn's The Structure of Scientific Revolutions (1962) historians, philosophers, and sociologists of science accept that novelty and sweeping reassessments are a structural part of the history of science and scientific knowledge. It is therefore hard to pin down what a "heretic" in science is, despite common usage of the term, because a dissenting scientist who defies current conventional wisdom of their colleagues can become a standard-bearer of a new consensus, (for example, Howard Temin) or permanently consigned to the ranks of conspiracy theorists and pseudoscientists (for example, HIV/AIDS denialist Peter Duesberg.)
The philosophers of science Oren Harman and Michael Dietrich therefore suggest using the term "iconoclast" to describe scientists who habitually seek novelty or chafe at scientists' social conventions, and "iconoclasm" to describe attempts to change the "iconic" theories and assumptions that form the heart of many scientific disciplines. See In this sense, Temin's "iconoclastic" theory of reverse transcription destroyed the "icon" of the Central Dogma that had been so essential in the early development of molecular biology (see 1.5 John Coffin — The Origin of Molecular Retrovirology)
For a fuller discussion see Oren Solomon Harman and Michael R. Dietrich, eds., Rebels, Mavericks, and Heretics in Biology (New Haven: Yale University Press, 2008).