Income Taxes (Deferred Tax Assets and Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Deferred tax assets (liabilities):
Stock-based compensation	$ 69,201	$ 66,827
Accruals and reserves	13,022	11,155
Depreciation and amortization	(11,159)	(18,356)
R&D credits	19,196	8,480
Other	824	(244)
Total deferred tax assets	91,084	67,862
Valuation allowance	(481)	0
Net deferred tax assets	$ 90,603	$ 67,862