Amortization Expense Included in Condensed Consolidated Statements of Operations (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Finite Lived Intangible Assets [Line Items]
Amortization expense	$ 363	$ 435	$ 726	$ 870
Cost of revenue
Finite Lived Intangible Assets [Line Items]
Amortization expense	111	97	223	193
Selling and marketing
Finite Lived Intangible Assets [Line Items]
Amortization expense	$ 252	$ 338	$ 503	$ 677