Business Acquisition - Allocation of Total Purchase Consideration (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Apr. 05, 2012	Dec. 31, 2011
Business Acquisition [Line Items]
Goodwill	$ 8,193	$ 8,193		$ 0
Other assets, cash			76
Sonar Limited
Business Acquisition [Line Items]
Acquired intangible assets			7,130
Goodwill			8,193
Other assets (including cash of $76)			815
Current liabilities			(506)
Deferred revenue			427
Borrowings			(557)
Net deferred tax liabilities			1,809
Net Assets Acquired			12,839
Sonar Limited | Developed technology
Business Acquisition [Line Items]
Acquired intangible assets			3,800
Sonar Limited | Customer relationships
Business Acquisition [Line Items]
Acquired intangible assets			2,400
Sonar Limited | Non-compete agreements
Business Acquisition [Line Items]
Acquired intangible assets			610
Sonar Limited | Domains/trademarks/tradenames
Business Acquisition [Line Items]
Acquired intangible assets			$ 320