Probably a sales- and engineering- heavy team; many of whom will be earning $150k+. Executives are probably making $300k+. This should bring up the average salary at the company.

Also, this is just one line-item. There's a lot more expenses to running a business. I wouldn't be surprised to see them close to $80M+ a year. The article didn't exactly say their revenues were $100M, just that it was "well on its way" there.