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Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

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-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13854-109267

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13777-109266

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-Name Accounting Standards Codification

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- Definition

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.

+ References

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Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

+ References

No definition available.

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- Definition

Number of reporting units tested for impairment of goodwill. A reporting unit is an operating segment or one level below an operating segment.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Reporting Unit

-URI http://asc.fasb.org/extlink&oid=6523643

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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No definition available.

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Summary of significant accounting policies (Details 3) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014 item	Dec. 31, 2013
Goodwill
Number of reporting units	1us-gaap_NumberOfReportingUnits
Number of operating segments	1us-gaap_NumberOfOperatingSegments
Number of reportable segments	1us-gaap_NumberOfReportableSegments
Goodwill impairment charges	$ 0us-gaap_GoodwillImpairmentLoss	$ 0us-gaap_GoodwillImpairmentLoss
Computer equipment \| Minimum
Property and equipment
Estimated useful lives	2 years
Computer equipment \| Maximum
Property and equipment
Estimated useful lives	5 years
Software \| Minimum
Property and equipment
Estimated useful lives	2 years
Software \| Maximum
Property and equipment
Estimated useful lives	5 years
Office equipment \| Minimum
Property and equipment
Estimated useful lives	3 years
Office equipment \| Maximum
Property and equipment
Estimated useful lives	5 years
Leasehold improvements \| Minimum
Property and equipment
Estimated useful lives	2 years
Leasehold improvements \| Maximum
Property and equipment
Estimated useful lives	15 years