Geographic Information - Schedule of Geographic Information (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
Segment Reporting [Abstract]
Entity Wide Revenue By Major Geography Percentage									10.00%
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	$ 50,151	$ 49,905	$ 48,611	$ 47,126	$ 47,689	$ 46,600	$ 43,375	$ 41,029	$ 195,793	$ 178,693	$ 145,763
U.S. [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues									143,819	135,876	112,693
Rest of world [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues									$ 51,974	$ 42,817	$ 33,070