Table:
|  | Year Ended December 31, |  |
| --- | --- | --- |
| (In thousands) | 2019 | 2018 |
| Opening balance | $ 13,783 | $ 8,469 |
| Additions | 157,121 | 6,215 |
| Acquisition adjustments | — | (901 ) |
| Effect of currency translation adjustment | 305 | — |
| Goodwill | $ 171,209 | $ 13,783 |
Paragraphs:
1. Goodwill and Other Intangible Assets
The changes in the carrying amount of goodwill for the years ended December 31, 2019 and 2018, are as follows:
Our 2019 acquisitions of DeliverySlip (as defined herein) and AppRiver (as defined herein) resulted in the addition to our goodwill balance in 2019. Our 2018 acquisition of Erado (as defined herein) resulted in the addition to our goodwill balance in 2018. Our 2018 acquisition adjustments to goodwill reflect the appropriate reallocation of excess purchase price from goodwill to acquired assets and liabilities related to our 2017 Greenview and EMS (as defined herein) purchases. We evaluate goodwill for impairment annually in the fourth quarter, or when there is reason to believe that the value has been diminished or impaired. There were no impairment indicators to the goodwill recorded as of December 31, 2019.
Question:
Which companies did zix acquire in 2019 and 2018 respectively?
Answer: DeliverySlip (as defined herein) and AppRiver (as defined herein), Erado