Summary of significant accounting policies (Details Textual)	3 Months Ended			3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Apr. 30, 2013	Mar. 31, 2013 Series A Convertible Preferred Stock [Member]
Summary Of Significant Accounting Policies [Line Items]
Convertible Preferred Stock, Shares Issued upon Conversion (in shares)	9,555		1,123,809	1,139,870
Warrants Antidilutive	920,829			4,038,753
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	96,667	52,667		307,667