The first 5 digits of a CUSIP identifies the issuer of a stock (BioAmber, Inc). The next 2 digits tell the type of stock - ie - in this case, the 10 likely meant "common stock" of BioAmber, Inc. The 90 would mean there is or was at one time another type of stock of BioAmber, would have to look as I never had a reason to see if there was. The last digit is a check digit.
It should be noted that Intracoastal Capital had warrants that required that filing and not actual shares. The warrants were and will always be "underwater."