Nature of business, basis of presentation and summary of significant accounting policies (Details Textual 1) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Amortization of debt discount and deferred financing costs	$ 64	$ 3
Depreciation expense	12	17
Patent amortization expense	365	372
Marketing expense	$ 15	$ 15
Estimated remaining weighted average useful lives of patents	5 years
Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	3 years
Estimated useful life of related assets, for patents amortization	5 years
Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	5 years
Estimated useful life of related assets, for patents amortization	7 years