Income Taxes (Deferred Tax Assets (Liabilities)) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets
Net operating loss carryforwards	$ 1,349	$ 1,725
Stock-based compensation	20,122	14,970
R&D and other credits	5,541	4,270
Reserves-noncurrent	8,080	7,018
Gross deferred tax assets	35,092	27,983
Deferred tax liabilities
Property and equipment	(4,779)	(4,123)
Intangible assets	(285)	(4,122)
Goodwill	(13,719)	(9,901)
Gross deferred tax liabilities	(18,783)	(18,146)
Net deferred tax assets and liabilities	$ 16,309	$ 9,837