Ann: FBR Quarterly Report and Cashflow, page-3

Not too surprised or concerned by a doubling between quarters, and I wouldn't read any particular strategy into it.
There will undoubtedly be different stages of the R&D to take experimental prototype to commercial prototype.

Writing software and drawing designs for hardware components isn't as costly as physically producing the hardware (many times over...) singularly for each part during the testing and getting things just right to perform just as they want it to.

Not to mention the trial and error process of getting the software to work on the hardware.
The engineering design team will have many episodes of feeling "wow, aren't we simply awesome" and "sad faces all round".