I assumed that the 70-75% conversion rate is much the same year...

I assumed that the 70-75% conversion rate is much the same year on year, so counted 30% of last years orders to get different numbers from yourself. Given that last year was a bit of a breakout in terms of revenue I ignored any orders carried over from the prior year and made the assumption that  

Revenue from orders carried over into 2019 from 2018 = 0.3 x 7.3 / 0.7 = $3.1m

Then revenue from orders in 2019 (recognised in 2019) = $7.3m - $12m

Other revenue I kept at $1m

Giving total revenue for 2019 in the range 11m - 16m (in round figures)

That gives revenue growth between 30% and 90%

All IMO and DYOR