Property and equipment, net - Schedule of Property, Plant and Equipment (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Property and Equipment	$ 6,092us-gaap_PropertyPlantAndEquipmentGross	$ 5,771us-gaap_PropertyPlantAndEquipmentGross
Capitalization of internal-use software	572	291
Accumulated depreciation	(2,595)	(2,141)
Property and equipment, net	3,497us-gaap_PropertyPlantAndEquipmentNet	3,630us-gaap_PropertyPlantAndEquipmentNet
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment	1,065	1,058
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment	3,279	3,247
Software [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment	874	874
Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and Equipment	$ 302	$ 301

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

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-Publisher FASB

-Name Accounting Standards Codification

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-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.14)

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- Definition

Amount before accumulated amortization of capitalized costs for computer software, including but not limited to, acquired and internally developed computer software.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 985

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (a)

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- Definition

Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

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-Publisher FASB

-Name Accounting Standards Codification

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-Subparagraph (SX 210.5-02.13)

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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

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-Publisher FASB

-Name Accounting Standards Codification

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 13

-Subparagraph a

-Article 5

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

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