Information about Geographic Areas - Revenue and Long-Lived Assets by Geographic Area (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
Total revenue:
Total revenue	$ 25,028	$ 26,435	$ 28,873	$ 26,265	$ 25,595	$ 24,535	$ 23,055	$ 22,731	$ 106,601	$ 95,916
Long-lived assets:
Total long-lived assets	5,945				6,410				5,945	6,410
North America [Member]
Total revenue:
Total revenue									97,858	85,910
Long-lived assets:
Total long-lived assets	1,353				1,597				1,353	1,597
Asia [Member]
Total revenue:
Total revenue									3,405	4,967
Long-lived assets:
Total long-lived assets	247				360				247	360
Europe [Member]
Total revenue:
Total revenue									5,338	5,039
Long-lived assets:
Total long-lived assets	$ 4,345				$ 4,453				$ 4,345	$ 4,453