Product segment and geographic information (Details) (USD $)	3 Months Ended		9 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Segment Reporting Information [Line Items]
Total sales	$ 5,587,632	$ 9,215,703	$ 27,953,945	$ 35,963,918
Video Recorder Products [Member]
Segment Reporting Information [Line Items]
Total sales	2,252,347	4,137,859	15,437,377	19,115,575
Tv Receiver Products [Member]
Segment Reporting Information [Line Items]
Total sales	3,076,013	4,629,434	11,781,107	14,747,645
Non Tv Receiver Products [Member]
Segment Reporting Information [Line Items]
Total sales	$ 259,272	$ 448,410	$ 735,461	$ 2,100,698