Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013	Sep. 30, 2013
Income Tax Disclosure [Abstract]
Income tax provisions associated with income from continuing operations	$ 1,212,000	$ 918,000	$ 2,678,000	$ 2,794,000
Effective tax rates	33.00%	21.20%	30.50%	26.70%
U.S. federal statutory tax rate	35.00%	35.00%	35.00%	35.00%
Permanent tax and discrete tax benefits	100,000	400,000	200,000	600,000
Federal R&D tax credits		400,000		400,000
Income tax expense from discontinued operations	0	300,000	0	300,000
Effective tax rate applied to discontinued operations		32.80%		32.80%
Unrecognized tax benefits including interest and penalties	900,000		900,000		1,000,000
Liability for unrecognized tax benefits to change significantly in the next 12 months	$ 0		$ 0