Summary of Significant Accounting Policies - Schedule of Revenue by Geographic Areas (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
Revenue from External Customer [Line Items]
Revenue	$ 54,975	$ 40,670	$ 103,995	$ 78,107
United States [Member]
Revenue from External Customer [Line Items]
Revenue	36,465	26,695	68,870	51,483
United Kingdom [Member]
Revenue from External Customer [Line Items]
Revenue	4,918	3,643	9,325	7,106
International - All Other [Member]
Revenue from External Customer [Line Items]
Revenue	$ 13,592	$ 10,332	$ 25,800	$ 19,518

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

Name:	us-gaap_Revenues
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration