Stockholders' equity (deficit) (Details)	Mar. 31, 2014	Dec. 31, 2013
Stockholders Equity Deficit Details
Warrants outstanding	26,669
Stock options outstanding	4,156
Options reserved for future issuance under the Company's 2007 Incentive Plan	49,268
Total reserved for future issuance	80,093

The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(i)-(ii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant