Trying to get it done before the economy tanks, I think. We're vastly overdue for a downturn, the economy was already over-juiced due to excessive tax cuts/etc, we just put five million households out of work for a month (most of which are contractors and will not even be getting back pay) and will be doing it again in less than two weeks (now that the Superbowl is over and we're not messing with FOOTBAWW we can get back to our regularly scheduled shutdown).
The US economy is extremely likely to slide into recession in the next 2-6 months. And when they do, it'll be a lot harder to get $7 billion for a knockoff IRC client.
It has been a few very good years for raising cash from private investors, but that is now slowly reversing. Best to IPO now while the stock market is still mostly bullish.