| Quarterly report | 10-Q | 1999-08-06 | 1999-06-30 |
| Employee stock plan | S-8 | 1999-05-27 | - |
| Quarterly report | 10-Q | 1999-05-12 | 1999-03-31 |
| Passive ownership stake (update) | SC 13G/A | 1999-04-27 | - |
| Proxy statement | DEF 14A | 1999-04-12 | 1999-05-14 |
| Passive ownership stake | SC 13G | 1999-04-12 | - |
| Annual report | 10-K | 1999-03-29 | 1998-12-31 |
| Activist ownership stake (update) | SC 13D/A | 1999-02-18 | - |
| Activist ownership stake (update) | SC 13D/A | 1999-02-17 | - |
| Activist ownership stake (update) | SC 13D/A | 1999-02-17 | - |
| Activist ownership stake (update) | SC 13D/A | 1999-02-17 | - |
| Activist ownership stake (update) | SC 13D/A | 1999-02-17 | - |
| Passive ownership stake (update) | SC 13G/A | 1999-02-16 | - |
| Passive ownership stake (update) | SC 13G/A | 1999-02-11 | - |
| 424B4 | - | 1999-02-03 | - |
| S-3/A | - | 1999-01-29 | - |
| Major company event | 8-K | 1999-01-22 | 1999-01-21 |
| 424A | - | 1999-01-21 | - |
| Securities registration | S-3 | 1999-01-11 | - |
| Major company event | 8-K | 1999-01-11 | 1999-01-11 |
| Quarterly report | 10-Q | 1998-11-13 | 1998-09-30 |
| Quarterly report | 10-Q | 1998-08-14 | 1998-06-30 |
| Major company event | 8-K | 1998-08-11 | 1998-05-29 |
| Activist ownership stake | SC 13D | 1998-06-08 | - |
| Activist ownership stake | SC 13D | 1998-06-08 | - |
| Activist ownership stake | SC 13D | 1998-06-08 | - |
| Quarterly report | 10-Q | 1998-05-15 | 1998-03-31 |
| Proxy statement | DEF 14A | 1998-05-11 | 1998-05-29 |
| Annual report (amended) | 10-K/A | 1998-04-30 | 1997-12-31 |
| Annual report | 10-K | 1998-03-31 | 1997-12-31 |
| Major company event | 8-K | 1998-03-09 | 1998-02-28 |
| Major company event | 8-K | 1998-02-13 | 1998-02-09 |
| Passive ownership stake | SC 13G | 1998-02-13 | - |
| Quarterly report | 10-Q | 1997-11-14 | 1997-09-30 |
| Passive ownership stake (update) | SC 13G/A | 1997-09-23 | - |
| Employee stock plan | S-8 | 1997-09-05 | - |
| Employee stock plan | S-8 | 1997-09-05 | - |
| Quarterly report | 10-Q | 1997-08-14 | 1997-06-30 |
| Major company event | 8-K | 1997-08-12 | 1997-07-25 |
| Activist ownership stake | SC 13D | 1997-08-05 | - |
| Activist ownership stake | SC 13D | 1997-08-05 | - |
| Passive ownership stake (update) | SC 13G/A | 1997-07-10 | - |
| Proxy statement | DEF 14A | 1997-07-02 | 1997-07-10 |
| Major company event | 8-K | 1997-07-02 | 1997-05-13 |
| Quarterly report (amended) | 10-Q/A | 1997-07-02 | 1997-03-31 |
| Annual report (amended) | 10-K/A | 1997-07-02 | 1996-12-31 |
| Quarterly report | 10-Q | 1997-05-09 | 1997-03-31 |
| Proxy statement | DEF 14A | 1997-04-18 | 1997-05-15 |
| Passive ownership stake (update) | SC 13G/A | 1997-04-09 | - |
| PRE 14A | - | 1997-04-04 | 1997-05-15 |
