Summary of Amortization Expense (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014
Product Revenues
Business Acquisition [Line Items]
Amortization expense	$ (119)	$ (235)
Amortization	119	235
Selling, General and Administrative Expense
Business Acquisition [Line Items]
Amortization expense	(548)	(1,081)
Amortization	$ 548	$ 1,081