| Passive ownership stake | SC 13G | 1999-09-27 | - |
| Quarterly report | 10-Q | 1999-08-11 | 1999-06-30 |
| Passive ownership stake | SC 13G | 1999-07-08 | - |
| Passive ownership stake | SC 13G | 1999-07-08 | - |
| 8-A12G/A | - | 1999-06-16 | - |
| Employee stock plan | S-8 | 1999-06-02 | - |
| Employee stock plan | S-8 | 1999-06-02 | - |
| 8-A12B/A | - | 1999-05-21 | - |
| Quarterly report | 10-Q | 1999-05-11 | 1999-03-31 |
| Passive ownership stake | SC 13G | 1999-05-10 | - |
| Activist ownership stake (update) | SC 13D/A | 1999-04-30 | - |
| Proxy statement | DEF 14A | 1999-03-17 | 1999-05-13 |
| 10-K405 | - | 1999-03-17 | 1998-12-31 |
| PRE 14A | - | 1999-03-05 | 1999-05-13 |
| Passive ownership stake | SC 13G | 1999-02-12 | - |
| Passive ownership stake (update) | SC 13G/A | 1999-02-12 | - |
| Passive ownership stake (update) | SC 13G/A | 1999-02-11 | - |
| Activist ownership stake (update) | SC 13D/A | 1999-02-08 | - |
| Activist ownership stake (update) | SC 13D/A | 1998-12-30 | - |
| Employee stock plan | S-8 | 1998-12-02 | - |
| Employee stock plan | S-8 | 1998-12-01 | - |
| Employee stock plan | S-8 | 1998-11-30 | - |
| Quarterly report | 10-Q | 1998-11-13 | 1998-09-30 |
| Activist ownership stake (update) | SC 13D/A | 1998-11-12 | - |
| Passive ownership stake (update) | SC 13G/A | 1998-09-18 | - |
| Passive ownership stake (update) | SC 13G/A | 1998-09-10 | - |
| Quarterly report | 10-Q | 1998-08-05 | 1998-06-30 |
| DEFR14A | - | 1998-07-08 | - |
| DEFS14A | - | 1998-05-26 | 1998-07-08 |
| Quarterly report (amended) | 10-Q/A | 1998-05-13 | 1998-03-31 |
| Quarterly report | 10-Q | 1998-05-12 | 1998-03-31 |
| PRES14A | - | 1998-05-08 | 1998-07-08 |
| Proxy statement | DEF 14A | 1998-03-18 | 1998-05-06 |
| 10-K405 | - | 1998-03-13 | 1997-12-31 |
| Passive ownership stake (update) | SC 13G/A | 1998-02-13 | - |
| Activist ownership stake | SC 13D | 1998-02-12 | - |
| Passive ownership stake (update) | SC 13G/A | 1998-02-11 | - |
| Passive ownership stake (update) | SC 13G/A | 1998-01-27 | - |
| Employee stock plan | S-8 | 1997-12-18 | - |
| Employee stock plan | S-8 | 1997-12-17 | - |
| Employee stock plan | S-8 | 1997-12-16 | - |
| Employee stock plan | S-8 | 1997-12-15 | - |
| Quarterly report | 10-Q | 1997-11-10 | 1997-09-30 |
| Quarterly report | 10-Q | 1997-08-08 | 1997-06-30 |
| Quarterly report | 10-Q | 1997-05-08 | 1997-03-31 |
| 8-A12B/A | - | 1997-05-01 | - |
| 10-K405 | - | 1997-03-21 | 1996-12-31 |
| Proxy statement | DEF 14A | 1997-03-18 | 1997-05-07 |
| PRE 14A | - | 1997-03-06 | 1999-05-01 |
| Passive ownership stake | SC 13G | 1997-02-13 | - |
