Sourcegraph's future with GitHub code search

GitHub recently launched a technology preview of their new code search, which is a lot like SG, and I'm wondering whether this is going to be a killer for Sourcegraph as a company? Even if SG is ahead on features right now, I expect GitHub to be able to close any significant gap quickly. And while SG already has many enterprise clients, I'm wondering if this is going to kill their growth potential, do you think companies that are already using GitHub and not yet SG are still likely to become SG users? I've been following SG and I really like their product and the company, this seems pretty bad for them, was wondering (and hoping that) my analysis is wrong. WDYT?