Happy Days maintained a fairly realistic bent throughout it's run (I'm not here to debate shark jumping, I promise). Two notable detours from this were Mork and Mindy and Out of the Blue. Mork seemed like an random introduction to the show, and would end up in Colorado on his show, far away from Milwaukee, so he wouldn't have even been considered a "TV neighbor" to the Cunninghams anyway.
What was the decision-making behind conceiving the Mork character within the Happy Days universe? Why was it decided that it was worth risking the alienation of the existing audience for a show that might not take off at all?