Summary of significant accounting policies (Narrative) (Details) (USD $)	3 Months Ended		6 Months Ended				6 Months Ended	12 Months Ended	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012	May 28, 2012	Jun. 30, 2013 Credit Concentration Risk [Member]	Dec. 31, 2012 Credit Concentration Risk [Member]	Jun. 30, 2013 Sales [Member] Energizer Holdings, Inc. [Member]	Jun. 30, 2012 Sales [Member] Energizer Holdings, Inc. [Member]
Concentrations of credit risk
Concentration risk, percentage							7.10%	16.00%	11.40%	17.80%
Deferred Revenue
Deferred government grants						$ 666,613
Loss per share of common stock attributable to the Company
Anti-dilutive securities excluded from calculation	612,500	727,500	612,500	727,500
Derivatives
Fair value balance of foreign currency derivative assets	$ 133,225		$ 133,225		$ 255,508