For big-screen movie company IMAX, the past several weeks must have seemed like the best of times and the worst of times. In the 13 years since Richard Gelfond and Bradley Wechsler, who share the titles of chairman and CEO, purchased the company from its Canadian founders, they have transformed IMAX from an attraction at museums and tourist locations into a network of theaters showing Hollywood blockbusters. The July 11 opening of Harry Potter and the Order of the Phoenix was the largest and most successful in IMAX history, with the IMAX version of the film setting a new single-day box office record and contributing .3 million of the movie’s 0 million domestic gross from July 11 through the weekend ending July 15. Yet despite the record box office, the company’s stock price remained moribund as it  delayed its financial filings to restate its revenue recognition for the years 2002-2005 and responded to an informal inquiry from the Securities and Exchange Commission.…