It sounds like "customer" here is defined as "corporation paying for a bunch of its employees", and not "one poor person who had lots of doctors visits". Elsew

It sounds like "customer" here is defined as "corporation paying for a bunch of its employees", and not "one poor person who had lots of doctors visits". Elsewhere in the S-1: "In 2017, 2018 and the nine months ended September 30, 2019, our top customers accounted for 42%, 37% and 36% of our net revenue, respectively. These customers included Google Inc., which accounted for 10% of our net revenue for 2018 and the nine months ended September 30, 2019." (Disclaimer: I work at Google, and they do pay for my One Medical membership.)