Non-vested options (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Non-vested options, beginning of year,share	1,128,250	671,500
Non-vested options, beginning of year,weighted avg. exercise price	$ 0.57	$ 0.89
Granted,share	581,000	810,000
Granted,weighted avg. exercise price	$ 0.36	$ 0.34
Vested,share	(367,600)	(330,050)
Vested,weighted avg.exercise price	$ 0.65	$ 0.69
Forfeited,share	(416,600)	(23,200)
Forfeited,Weighted avg. exercise price	$ 0.52	$ 1.21
Non-vested options, end of year,share	925,050	1,128,250
Non-vested options, end of year,Weighted avg. exercise price	$ 0.42	$ 0.57