Income Taxes (Schedule Of Company's Deferred Tax Assets) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Income Taxes [Abstract]
Deferred revenue	$ 54,116	$ 76,638
Net operating loss carry forward	30,767	4,786
Stock-based compensation	9,872	8,243
Research and development credits	11,280	3,280
Depreciation, amortization and other	133	120
Accruals and reserves	552	729
Total deferred tax assets	106,720	93,796
Less: valuation allowance	(106,720)	(93,796)
Net deferred tax assets	$ 0	$ 0