Dozens may be a bit of an exaggeration, but they give a big picture breakdown of their employment ratios in their annual report;

    As of December 31, 2014, we had 6,897 employees,
    consisting of 2,838 employees in engineering, product
    development and customer operations, 2,989
    employees in sales and marketing, and 1,070
    employees in general and administrative functions.

So even broadly, 60% of the company is definitely non-engineering. From a quick glance at their 10k, it looks like about 1,700 people are in the product development group, so at minimum 75% of the company is non-engineering. Whether it's 1/5 engineers or somewhere closer to 1/10, it's hard to say but it takes a lot of people to run a company, and the majority don't make 'engineer' salaries.