Here is information on SEC Form D:

"Regulation D is a series of rules that govern commonly used regulatory exemptions that companies can use to sell securities.  Regulation D requires that companies file a notice of their offering with the SEC using Form D."

"Companies must file this notice . . . within 15 days after the first sale of securities. An amendment is required annually if the offering is ongoing for more than 12 months, or if certain of the information in the notice changes."

The 'A' - Form D/A - indicates filing an amendment to the orginal Form D.

Apparently there were three Form Ds filed in the past - looks like November 2018.