Quarterly Financial Information (Detail) (USD $)	3 Months Ended								12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2013
Quarterly Financial Information Disclosure [Abstract]
Net revenue	$ 4,910,000	$ 10,547,000	$ 14,541,000	$ 10,019,000	$ 7,568,000	$ 18,690,000	$ 17,737,000	$ 4,948,000	$ 40,017,000	$ 48,943,000
Production costs	4,590,000	8,266,000	10,851,000	8,487,000	6,278,000	13,720,000	13,411,000	4,531,000	32,194,000	37,940,000
Gross profit	320,000	2,281,000	3,690,000	1,532,000	1,290,000	4,970,000	4,326,000	417,000
Production engineering and development	339,000	352,000	351,000	380,000	391,000	420,000	454,000	448,000	1,422,000	1,713,000
Selling, general and administrative	1,617,000	1,557,000	1,519,000	1,734,000	902,000	1,867,000	1,984,000	1,959,000	6,427,000	6,712,000
Income (loss) from operations	(1,636,000)	372,000	1,820,000	(582,000)	(3,000)	2,683,000	1,888,000	(1,990,000)	(26,000)	2,578,000
Other income (expense), net	(473,000)	2,268,000	1,181,000	1,463,000	1,075,000	679,000	1,822,000	179,000	4,439,000	3,755,000
Income (loss) before income tax expense	(2,109,000)	2,640,000	3,001,000	881,000	1,072,000	3,362,000	3,710,000	(1,811,000)	4,413,000	6,333,000
Income tax expense (benefit)	(1,572,000)	977,000	1,100,000	435,000	(1,163,000)	873,000	733,000	(835,000)	940,000	(392,000)
Net income (loss)	$ (537,000)	$ 1,663,000	$ 1,901,000	$ 446,000	$ 2,235,000	$ 2,489,000	$ 2,977,000	$ (976,000)	$ 3,473,000	$ 6,725,000
Basic earnings (loss) per share	$ (0.06)	$ 0.17	$ 0.20	$ 0.05	$ 0.24	$ 0.26	$ 0.31	$ (0.10)	$ 0.36	$ 0.71
Diluted earnings (loss) per share	$ (0.06)	$ 0.17	$ 0.20	$ 0.05	$ 0.24	$ 0.26	$ 0.31	$ (0.10)	$ 0.36	$ 0.71