Restructuring Expense (Details) (Kendall Square Facility)	1 Months Ended		12 Months Ended
	Jun. 30, 2003	Jan. 31, 2003	Dec. 31, 2006	Dec. 31, 2003
Kendall Square Facility
Kendall Square Lease
Leased area (in square feet)	290,000
Lease term (in years)		15
Occupied leased area (in square feet)			120,000
Discount rate, lease restructuring liability (as a percent)				10.00%