Amortization Expense Included in Condensed Consolidated Statements of Operations (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Amortization expense	$ 1,259	$ 949	$ 2,420	$ 1,736
Cost of revenue
Amortization expense	366	225	703	346
Selling and marketing
Amortization expense	$ 893	$ 724	$ 1,717	$ 1,390

The aggregate expense charged against earnings to allocate the cost of acquired intangible assets. As a noncash expense, this element is added back to net income when calculating cash provided by (used in) operations using the indirect method.

No definition available.

Name:	us-gaap_AmortizationOfAcquiredIntangibleAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration