"You can't open the application 'Glyphs.app' because..."

“…it may be damaged or incomplete.”
I had a file open and minimized but needed to restart my MacBook Pro 15" Retina Display on 29 Sept. Glyphs asked if I wanted to save the file; I chose ‘Don’t save’. Next time I tried to open Glyphs, two days later, I got the “damaged or incomplete” error message. Not sure which build I was using, but I had the Cutting Edge preference set.
Is there a way to repair this? “Get info” on Glyphs in the Applications folder shows this:

Did you try re-downloading?

I haven’t yet, as I wasn’t sure whether the licensing would be a problem. Don’t want to have to buy it again…but it sounds like that won’t be an issue.