Income Taxes (Components of Loss Before Provision for Income Taxes) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Line Items]
Loss before provision for income taxes	$ (19,327)	$ (41,390)	$ (30,587)
United States [Member]
Income Tax Disclosure [Line Items]
Loss before provision for income taxes	(20,980)	(41,696)	(30,743)
Foreign [Member]
Income Tax Disclosure [Line Items]
Loss before provision for income taxes	$ 1,653	$ 306	$ 156