Segment Reporting - Schedule of Revenue by Geographic Segments (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]
Total	$ 43,032	$ 40,468	$ 41,085	$ 42,039	$ 39,034	$ 37,982	$ 38,496	$ 34,349	$ 166,624	$ 149,861	$ 123,212
% of Total									100.00%	100.00%	100.00%
United States [Member]
Segment Reporting Information [Line Items]
Total									91,037	78,653	56,728
% of Total									54.70%	52.50%	46.10%
United Kingdom [Member]
Segment Reporting Information [Line Items]
Total									7,029	5,214	5,322
% of Total									4.20%	3.50%	4.30%
Germany [Member]
Segment Reporting Information [Line Items]
Total									18,331	19,717	17,035
% of Total									11.00%	13.10%	13.80%
Japan [Member]
Segment Reporting Information [Line Items]
Total									49,706	45,739	43,299
% of Total									29.80%	30.50%	35.10%
Other Asia [Member]
Segment Reporting Information [Line Items]
Total									$ 521	$ 538	$ 828
% of Total									0.30%	0.40%	0.70%