What is a brief overview of the Ikhwan al-Safa and who follows their approach now?

"Ikhwan al-Safa" (Brethren of Purity) was a secret esoteric group that emerged in Basra. They blended Greek philosophy and esoteric beliefs with Islam. Their goal was to eliminate Islam and its state. They have "Rasa'il Ikhwan al-Safa" (Epistles of the Brethren of Purity), about fifty epistles containing their philosophical ideas. Among their beliefs are the unity of existence (wahdat al-wujud), the infallibility of the Imam, the acquisition of prophethood, the unity of religions, the dissolution of religious obligations (fara'id), and their assertion that knowledge has an outward and an inward meaning. They are an extension of the Ismaili esoteric movement, and whoever adopts their ideas and statements follows their path.