Space-X has a big order book, but that's not investment funding. That's potential future sales. Space-X only gets paid when they deliver a successful launch.

Space-X has had a huge future launch manifest for years, but they've never been able to keep up with their announced launch schedule. Now they no longer put dates on their launch manifest. Compare the current manifest [1] with one from a year ago [2] They're about 15 missions behind their announced schedule from last year.

[1] http://www.spacex.com/missions [2] https://web.archive.org/web/20140917002523/http://www.spacex...