| Form type | Document | Filing | Description | Filing date | Reporting date | File number(s) | 
|---|---|---|---|---|---|---|
| 4 | Open Document | Open Filing | May 25, 2022 | May 23, 2022 | 000-21617 | |
| 4 | Open Document | Open Filing | Aug 18, 2020 | Aug 16, 2020 | 000-21617 | |
| 4 | Open Document | Open Filing | Nov 22, 2019 | Nov 20, 2019 | 000-21617 | |
| 4 | Open Document | Open Filing | Dec 17, 2018 | Dec 4, 2018 | 000-21617 | |
| 3/A | Open Document | Open Filing | Jan 23, 2018 | Oct 2, 2017 | 000-21617 | |
| 3 | Open Document | Open Filing | Oct 5, 2017 | Oct 2, 2017 | 000-21617 |