Summary Of Significant Accounting Policies Summary Of Significant Accounting Policies (Schedule of Non-Cash ESOP and 401(k) expense by operation statement classification) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Summary Of Significant Accounting Policies [Line Items]
Employee Stock Ownership Plan And 401 K Compensation Expense	$ 3,855	$ 4,344	$ 11,552	$ 8,582
General and Administrative Expense [Member]
Summary Of Significant Accounting Policies [Line Items]
Employee Stock Ownership Plan And 401 K Compensation Expense	2,452	2,528	6,835	5,064
Research and Development Expense [Member]
Summary Of Significant Accounting Policies [Line Items]
Employee Stock Ownership Plan And 401 K Compensation Expense	$ 1,403	$ 1,816	$ 4,717	$ 3,518