Fair value measurement (Details) (Recurring basis, USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Level 1
Assets:
Money market accounts	$ 2,229	$ 5,602
Total assets	2,229	5,602
Level 2
Assets:
Marketable securities		1,614
Total assets		1,614
Level 3
Liabilities:
Contingent consideration	17	131
Total liabilities	17	131
Total
Assets:
Money market accounts	2,229	5,602
Marketable securities		1,614
Total assets	2,229	7,216
Liabilities:
Contingent consideration	17	131
Total liabilities	$ 17	$ 131

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash

-URI http://asc.fasb.org/extlink&oid=6506951

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash Equivalents

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Fair value of contingent consideration in a business combination that is classified in shareholders' equity.

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Fair value of financial and nonfinancial obligations.

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