Information about Geographic Areas - Revenue and Long-Lived Assets by Geographic Area (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013
Total revenue:
Total revenue	$ 25,595	$ 24,535	$ 23,055	$ 22,731	$ 25,829	$ 23,572	$ 21,837	$ 20,870	$ 95,916	$ 92,108
Long-lived assets:
Total long-lived assets	6,410				5,625				6,410	5,625
North America [Member]
Total revenue:
Total revenue									85,910	80,412
Long-lived assets:
Total long-lived assets	1,597				678				1,597	678
Asia [Member]
Total revenue:
Total revenue									4,967	7,314
Long-lived assets:
Total long-lived assets	360				403				360	403
Europe [Member]
Total revenue:
Total revenue									5,039	4,382
Long-lived assets:
Total long-lived assets	$ 4,453				$ 4,544				$ 4,453	$ 4,544