Income Taxes - Significant Components of Deferred Tax Assets and Liabilities (Detail) (USD $)	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Income Tax Disclosure [Abstract]
Net operating loss carryforwards	$ 155,960,858	$ 135,430,308	$ 117,027,433
Deferred revenue	504,143	1,570,370	2,960,454
Research credit carryforwards	9,185,508	11,202,848	11,560,603
Capitalized license fees and patents	10,176,119	2,017,029	2,342,589
Capitalized research and development costs	29,705	99,671	263,942
Share-based compensation and options	8,452,457	6,979,532	5,586,697
Foreign tax credits			595,912
Other	3,404,764	2,579,478	1,480,613
Deferred income tax assets	187,713,554	159,879,236	141,818,243
Deferred tax liabilities:
Other	(162,824)	(322,779)	(479,941)
Deferred tax liabilities	(162,824)	(322,779)	(479,941)
Less valuation allowance for net deferred income tax assets	(187,550,730)	(159,556,457)	(141,338,302)
Net deferred tax assets / (liabilities)