Stock incentive plan and stock-based compensation (Tables)

12 Months Ended

Dec. 31, 2015

Disclosure Of Compensation Related Costs, Share-Based Payments [Abstract]

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]

	Number  of shares			Weighted average grant date fair value
Non–vested at January 1, 2014		52,667		$	4.56
Granted		147,000			1.72
Vested		(77,000	)		3.77
Forfeited		(12,667	)		3.68
Non–vested at December 31, 2014		110,000			1.42
Granted		255,000			0.31
Vested		(309,500	)		0.53
Forfeited		(55,500	)		1.28
Non–vested at December 31, 2015		–		$	–

Schedule of Stockholders' Equity Note, Warrants or Rights [Table Text Block]

	Warrants  outstanding		Weighted average exercise price
At January 1, 2014		920,825	$	3.44
Issued		100,000		–
Exercised		–		3.75
Expired		–		–
At December 31, 2014		1,020,825	$	3.47
Issued		2,800,000		0.25
Exercised		–		–
Expired		–		–
At December 31, 2015		3,820,825	$	1.11