Segment Reporting - Schedule of Revenue by Geographic Segments (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Segment Reporting Information [Line Items]
Total	$ 47,063	$ 40,468	$ 138,098	$ 123,592
% of Total	100.00%	100.00%	100.00%	100.00%
United States [Member]
Segment Reporting Information [Line Items]
Total	25,041	21,405	73,579	68,911
% of Total	53.20%	52.90%	53.30%	55.70%
United Kingdom [Member]
Segment Reporting Information [Line Items]
Total	2,248	2,223	7,577	5,168
% of Total	4.80%	5.50%	5.50%	4.20%
Germany [Member]
Segment Reporting Information [Line Items]
Total	7,131	5,059	15,818	13,179
% of Total	15.20%	12.50%	11.50%	10.70%
Japan [Member]
Segment Reporting Information [Line Items]
Total	12,449	11,651	40,530	35,958
% of Total	26.40%	28.80%	29.30%	29.10%
Other Asia [Member]
Segment Reporting Information [Line Items]
Total	$ 194	$ 130	$ 594	$ 376
% of Total	0.40%	0.30%	0.40%	0.30%