NantWorks, the biotech firm founded by billionaire Dr. Patrick Soon-Schiong, is apparently working on an expansion of its Culver City headquarters. According to documents from the Culver City Planning Division, the five-year-old company is planning a new building at 9919 Jefferson Boulevard, directly across the street from its headquarters.  The proposed three-story structure would feature more than 62,000 square feet for corporate offices, research and development and laboratory purposes.  Plans also call for a rooftop deck and a detached five-story parking structure, with accommodations for 294 vehicles and 49 bicycles. The expansion is being designed by Santa Monica-based architecture firm Tichenor & Thorp, with assistance from Los Angeles-based Gruen Associates.  Renderings portray the office building as a contemporary low-rise structure, clad with perforated metal, cement plaster and panel glass.  The parking garage, located at the rear of the property adjacent to Ballona Creek, would be partially obscured through mesh panels, painted cement and exterior planters. Additional details, such as the project’s budget and construction timeline, are currently unclear.