Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Sep. 30, 2011
Income Tax Disclosure [Line Items]
U.S. federal statutory tax rate	35.00%		35.00%	35.00%
Federal research and development credit	$ 324,000	$ 200,000		$ 53,000
Income tax expense from discontinued operations	500,000		1,100,000
Income tax benefit from the sale of discontinued operations				13,800,000
Income tax benefit from discontinued operations			600,000
Net Reversal of Deferred Tax Asset Valuation Allowances	1,200,000
Valuation allowance			300,000
Unrecognized tax benefits including interest and penalties	1,000,000		1,000,000	1,100,000
Liability for unrecognized tax benefits to change significantly in the next 12 months	700,000		800,000	700,000
Maximum [Member]
Income Tax Disclosure [Line Items]
Valuation allowance				$ 100,000