15. 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 two customers that exceeded 10% of total revenues for the nine months ended September 30, 2022 were 39% and 27%. The accounts receivable from the top two customers by revenue were 6%, and 53%, respectively, as well as 17% and 19% from two other customers of the total accounts receivable as of September 30, 2022.

Revenues from three customers that exceeded 10% of total revenues for the nine months ended September 30, 2021 were 33%, 38%, and 24%. The accounts receivable from the top three customers by revenue were 16%, 17%, and 0%, respectively, as well as 18% from one other customer of the total accounts receivable as of September 30, 2021.

The Company’s financial instruments that are exposed to concentrations of credit risk consist primarily of cash, cash equivalents and marketable securities. 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. Such cash balances are currently in excess of the FDIC insurance limit of $250 thousand. As of September 30, 2022, the total amount exceeding such limit was $1,156 thousand. The Company has not experienced any credit losses associated with its cash balances in the past. The Company invests its cash equivalents in U.S. treasury bills with original maturities of three months or less.

Marketable securities are comprised of U.S. treasury bills with original maturities greater than three months. The Company has not experienced any losses in such accounts. The Company believes it is not exposed to any significant credit risk on cash, cash equivalents, and marketable securities and performs periodic evaluations of the credit standing of such institutions.