Segment Information and Information about Geographic Area (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 segment	Sep. 30, 2012
Segment Reporting Information [Line Items]
Number of operating segments			1
Revenues	$ 27,749	$ 23,382	$ 78,923	$ 66,763
United States
Segment Reporting Information [Line Items]
Revenues	19,943	16,063	55,750	45,644
Other
Segment Reporting Information [Line Items]
Revenues	$ 7,806	$ 7,319	$ 23,173	$ 21,119

Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

No definition available.

Name:	us-gaap_NumberOfOperatingSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration