Segment Information - Geographical Segment Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Total	$ 5,386	$ 6,927	$ 17,173	$ 19,795
Domestic [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total	1,733	3,046	5,178	7,946
International [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total	$ 3,653	$ 3,881	$ 11,995	$ 11,849