Fortune 1000 rank: 620
Best Companies rank: 43
No. of U.S. employees: 5,920
Most common salaried job (Avg. Pay):
What makes it so great? This biotech, which focuses on rare genetic disorders, celebrated its 25th anniversary in 2006 with events at all locations. From 96% to 98% of employees have been given stock options every year for the past 15 years.