Income Taxes Income Taxes (Schedule of Difference Between Effective and Statutory) (Details)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Income Tax Disclosure [Abstract]
United States federal income tax rate	35.00%	35.00%	35.00%
State taxes	2.80%	2.90%	3.70%
Nondeductible stock-based compensation	0.80%	0.10%	1.20%
United States federal and state research and development credits	(2.40%)	(2.60%)	(1.40%)
Change in state tax rates	(0.10%)	0.50%	0.00%
Foreign earnings	(2.20%)	(0.40%)	0.10%
Expiration of capital loss carryforward	2.10%	0.00%	0.00%
Other	0.90%	(1.00%)	(0.10%)
Change in the deferred tax asset valuation allowance	(2.30%)	0.20%	0.00%
Effective Income Tax Rate, Continuing Operations	34.60%	34.70%	38.50%