Doesn't the R&D ramp look a bit unusual? 57 -> 79 -> 141? Totally destroys their margins, right in the year when they must know they're going public?

As a percent of revenue the R&D increase doesn't look as crazy.

R&D as % of Revenue by year:

2013 39%

2014 37%

2015 44%

The marketing and sales expense goes from 13% to 21% of revenue in 2015

The growth in these line items really compress their margins in 2015.