Beautiful quarter - Atlas 400% growth and 1/3 of revenue. They are doing exactly what they need to do.
At my employer, we are just starting to use Mongo in most new projects. We are converting our pilots and promises and little one-offs into real projects, with real revenue that Mongo will recognize - in the next 5 years. At large enterprises, these are slow processes, but once started they are really hard to reverse. Oracle is already going from 100% of our new projects 2 years ago to 50% this year - and I expect that to stabilize around 25% in a few years.
Just to iterate my view, MDB has won the generic NoSql db wars - only they can shoot themselves in the foot. Otherwise they are going to win for 20 years, and that’s how long I’ll be holding.
I have to admit that I’m a bit concerned that even though I have other winners like TTD and TWLO, MDB is growing too much - they are getting close to 50% of my portfolio if they hold this ~20% gain tomorrow. Good problem to have 
If you aren’t in, I think any time is a good time to buy because of the long time horizon. But do expect big drops also. As long as they occur on news - like the Amazon DocumentDB thing, they will probably be great buying opportunities. The only drop I’ll worry about is one based on a reduction in revenue growth, not related to over all tech spend.