11.    Concentrations of Risk

The Company’s revenues are concentrated in a small group of customers with some individually having more than 10% of total revenues.  Revenues from three customers that exceeded 10% of total revenues for the six months ended June 30,  2020 were 23%,  27% and 39%.  Accounts receivable from four customers were 59%, 13%, 12% and 11% of the total accounts receivable as of June 30, 2020.  For the six months ended June 30, 2019, two customers exceeded 10% of revenues and were 53%, and 15% of total revenues.  Accounts receivable from one customers was 60% of the total accounts receivable as of June  30, 2019.

The Company’s financial instruments that are exposed to concentrations of credit risk consist primarily of cash. Cash balances are maintained principally at major U.S. financial institutions and are insured by the Federal Deposit Insurance Corporation (“FDIC”) up to regulatory limits. From time to time, cash balances may exceed the FDIC insurance limit. The Company has not experienced any credit losses associated with its cash balances in the past.