While sales increased in the most recent quarter, almost 25 percent of its business was with a single customer.
The shares, worth a total of about $320 million, were bought by a single customer.
That adds up to a lot of time and expense for a single customer.
In education no single customer is always right, people aren't all looking for the same things.
Now, a single customer may buy up to a thousand dollars' worth.
A huge contract with a single big customer can be a threat to your business rather than an opportunity.
"I never saw a single customer who bought a copy of that book buy anything else," he says.
The original plan had been to sell them to a single sovereign customer.
Three-quarters of these companies are small and usually work for a single customer.
"I don't believe there is a single customer in the world who wants a marketing relationship with a company," he said.