Stockholders' equity: (Details 4) (USD $)	12 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2011
Stock-based compensation
Pretax compensation expense	$ 51,804	$ 288,100	$ 574,150
Share based compensation expense, net of tax	51,804	288,100	574,150
Restricted stock | Director
Stock-based compensation
Pretax compensation expense	34,438	236,000	542,619
Share based compensation expense, net of tax	34,438	236,000	542,619
Stock options
Stock-based compensation
Pretax compensation expense	17,366	52,100	31,531
Share based compensation expense, net of tax	$ 17,366	$ 52,100	$ 31,531