2017 revenue: $79.6MM
2018 revenue (est): $117.8MM
2019 revenue (est): $164.9MM
2020 revenue (est): $214.3MM
Safe guess potentially 10x current year (2019) which would be $1.6B.
Considering that they need an IPO pop the shares would be priced about 20-25% lower, bringing them back to that $1.3B private round valuation.
Unless the bankers are very optimistic and it will trade higher in which case they would be looking to price at the $1.6-1.7B range and hope that it pops to $2B at open.