Industry and Geographic Information - Long-lived Assets (Excluding Intangible Assets) and Total Net Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, Total					$ 52,547					$ 52,547	$ 49,226
Total revenues	$ 52,412	$ 46,812	$ 35,204	$ 61,701	63,953	$ 41,193	$ 31,883	$ 47,129	$ 196,129	184,158	177,325
Federal [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, Total					52,426					52,426	49,052
Total revenues									168,809	159,845	154,626
Foreign [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Long-lived assets, Total					$ 121					121	174
Total revenues									$ 27,320	$ 24,313	$ 22,699