Product Revenue, Net - Product Revenue by Customer (Details) (Sales Revenue, Product Line [Member], Customer Concentration Risk [Member])	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Customer A [Member]
Concentration Risk [Line Items]
Customer percentage of product revenue	29.00%	29.00%
Customer B [Member]
Concentration Risk [Line Items]
Customer percentage of product revenue	21.00%	19.00%
Customer C [Member]
Concentration Risk [Line Items]
Customer percentage of product revenue	16.00%	12.00%
Customer D [Member]
Concentration Risk [Line Items]
Customer percentage of product revenue	13.00%	8.00%
Customer E [Member]
Concentration Risk [Line Items]
Customer percentage of product revenue	10.00%	13.00%