Orders in the fourth quarter were 129% above the number of orders in the fourth quarter of 2018 and 31% sequentially above the third quarter of 2019. In the third quarter of 2019, orders grew 95% year-over-year.
Due to the accelerating increase in orders and strong collections on orders received in prior periods the Company has updated its previous estimate for fourth quarter revenue to between $14.0 and $14.5 million. The Company previously provided guidance for revenue in the fourth quarter 2019 of between $12.3 and $12.8 million. The updated guidance places the full year revenue estimate between $45.3 and $45.8 million.
The updated revenue estimate is now approximately 50% to 55% above last year's fourth quarter revenue of $9.3 million.
Fourth quarter 2019 estimated adjusted EBITDA has been updated to between $3.6 and $4.1 million. The earlier estimate was between $2.3 and $2.8 million.