Stockholders' Equity (Details 4) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Allocation of stock-based compensation expense
Stock-based compensation expense (benefit) related to employee and non-employee stock options and the ESPP	$ 9,845	$ 12,159	$ 11,827
Research and development
Allocation of stock-based compensation expense
Stock-based compensation expense (benefit) related to employee and non-employee stock options and the ESPP	8,527	10,148	10,977
General and administrative
Allocation of stock-based compensation expense
Stock-based compensation expense (benefit) related to employee and non-employee stock options and the ESPP	1,318	2,011	2,408
Non-cash compensation expense related to stock options included in continuing operations
Allocation of stock-based compensation expense
Stock-based compensation expense (benefit) related to employee and non-employee stock options and the ESPP	9,845	12,159	13,385
Non-cash Compensation Expense Related to Stock Options Included in Discontinued Operations
Allocation of stock-based compensation expense
Stock-based compensation expense (benefit) related to employee and non-employee stock options and the ESPP			$ (1,558)