Stock-based compensation (Details) (USD $)	6 Months Ended	12 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Outstanding at beginning of period, Shares	100,000
Granted, Shares	0
Expired and forfeited, Shares	0
Exercised, Shares	0
Outstanding at end of period, Shares	100,000	100,000
Exercisable, Shares	100,000
Outstanding at beginning of period, Weighted-Average Exercise Price	$ 0.38
Granted, Weighted-Average Exercise Price	$ 0
Expired and forfeited, Weighted-Average Exercise Price	$ 0
Exercised, Weighted-Average Exercise Price	$ 0
Outstanding at end of period, Weighted-Average Exercise Price	$ 0.38	$ 0.38
Exercisable, Weighted-Average Exercise Price	$ 0.38
Outstanding, Remaining Contractual Term (in years)	1 month 17 days	1 month 17 days
Exercisable, Remaining Contractual Term (in years)	1 month 17 days