Stock-Based Compensation Expense Resulting from ESPP (Detail) (2011 Employee Stock Purchase Plan, USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Equity Based Compensation Related To Employee Stock Purchase Programs [Line Items]
Stock-Based Compensation Expense	$ 38	$ 67	$ 151	$ 143
Cost of revenue
Equity Based Compensation Related To Employee Stock Purchase Programs [Line Items]
Stock-Based Compensation Expense	11	14	39	28
Research and development
Equity Based Compensation Related To Employee Stock Purchase Programs [Line Items]
Stock-Based Compensation Expense	3	11	24	27
Selling and marketing
Equity Based Compensation Related To Employee Stock Purchase Programs [Line Items]
Stock-Based Compensation Expense	9	26	42	50
General and administrative
Equity Based Compensation Related To Employee Stock Purchase Programs [Line Items]
Stock-Based Compensation Expense	$ 15	$ 16	$ 46	$ 38