| Quarterly report | 10-Q | 1998-05-08 | 1998-03-31 |
| Proxy statement | DEF 14A | 1998-04-15 | 1997-12-31 |
| Passive ownership stake (update) | SC 13G/A | 1998-04-09 | - |
| Passive ownership stake (update) | SC 13G/A | 1998-04-09 | - |
| Annual report | 10-K | 1998-03-23 | 1997-12-31 |
| Employee stock plan | S-8 | 1998-03-18 | - |
| Passive ownership stake | SC 13G | 1998-02-17 | - |
| Passive ownership stake (update) | SC 13G/A | 1998-02-17 | - |
| Passive ownership stake (update) | SC 13G/A | 1998-02-11 | - |
| Passive ownership stake (update) | SC 13G/A | 1998-02-10 | - |
| Passive ownership stake (update) | SC 13G/A | 1998-02-06 | - |
| Passive ownership stake (update) | SC 13G/A | 1998-02-06 | - |
| Passive ownership stake (update) | SC 13G/A | 1998-02-03 | - |
| Quarterly report | 10-Q | 1997-11-13 | 1997-09-30 |
| Passive ownership stake | SC 13G | 1997-11-10 | - |
| Employee stock plan | S-8 | 1997-09-25 | - |
| 424B1 | - | 1997-09-12 | - |
| S-3MEF | - | 1997-09-12 | - |
| 424A | - | 1997-08-22 | - |
| Securities registration | S-3 | 1997-08-13 | - |
| Quarterly report | 10-Q | 1997-08-13 | 1997-06-30 |
| Annual report (amended) | 10-K/A | 1997-08-13 | 1996-12-31 |
| Passive ownership stake (update) | SC 13G/A | 1997-08-11 | - |
| Quarterly report | 10-Q | 1997-05-13 | 1997-03-31 |
| Proxy statement | DEF 14A | 1997-04-25 | 1997-05-14 |
| Annual report | 10-K | 1997-03-27 | 1996-12-31 |
| Passive ownership stake (update) | SC 13G/A | 1997-03-12 | - |
| Passive ownership stake | SC 13G | 1997-02-21 | - |
| Passive ownership stake (update) | SC 13G/A | 1997-02-18 | - |
| Passive ownership stake | SC 13G | 1997-02-14 | - |
| Passive ownership stake | SC 13G | 1997-02-13 | - |
| Passive ownership stake | SC 13G | 1997-02-12 | - |
| Passive ownership stake | SC 13G | 1997-02-11 | - |
| Passive ownership stake | SC 13G | 1997-02-06 | - |
| Passive ownership stake | SC 13G | 1997-01-13 | - |
| Major company event | 8-K | 1996-12-12 | 1996-12-12 |
| Quarterly report | 10-Q | 1996-11-13 | 1996-09-30 |
| Passive ownership stake | SC 13G | 1996-10-10 | - |
| Quarterly report | 10-Q | 1996-08-13 | 1996-06-30 |
| Major company event (amended) | 8-K/A | 1996-07-15 | 1996-05-02 |
| Employee stock plan | S-8 | 1996-06-20 | - |
| Major company event | 8-K | 1996-05-17 | 1996-05-02 |
| Quarterly report | 10-Q | 1996-05-15 | 1996-03-31 |
