Complex sentence: The development of Wallace's publishing and editing career then got very complicated: in 1999 the "Cosmos Books" name was licensed out to Wildside Press, at which point output increased dramatically, expanding with American and Australian authors.
Split into simpler sentences: The development of Wallace's publishing and editing career then got very complicated. In 1999 the company name was licensed out to Wildside Press, at which point output increased dramatically, branching out with American and Australian authors.