Property, Equipment and Software, Net (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Internally developed software	$ 34,107	$ 16,023
Computer equipment	12,169	7,929
Leasehold improvements	8,868	4,802
Purchased software	4,843	3,326
Furniture and fixtures	4,232	2,405
Construction in progress	2,165	549
Total property, equipment and software	66,384	35,034
Accumulated depreciation and amortization	(19,288)	(7,983)
Total property, equipment and software, net	$ 47,096	$ 27,051