Segment Information - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues from customers	$ 24,721	[1]	$ 19,944	[1]
Revenue percentage from other international country to the company's total revenue	10.00%		10.00%
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues from customers	$ 14,295		$ 11,961

[1] Includes related party revenue (Note 10) $ 42 $ 880