Income Taxes - Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Sep. 30, 2014
Deferred tax assets:
Net operating loss carryforward	$ 17,650	$ 18,618
Research credit carryforward	5,759	5,018
Accrued bonus	5,400	8,484
Investments	1,042	1,059
Accrued compensation	1,834	1,381
Share-based compensation	23,741	20,238
Deferred revenue	979	629
Accrued lease costs	5,009	1,007
Property and equipment	3,249	2,837
Other	5,613	4,731
Deferred tax assets, gross	70,276	64,002
Less valuation allowance	(13,882)	(12,078)
Total deferred tax assets	56,394	51,924
Deferred tax liabilities:
Intangible assets	(30,286)	(27,391)
Prepaid expense	(3,877)	(3,966)
Other	(993)	(993)
Total deferred tax liabilities	(35,156)	(32,350)
Deferred tax assets, net	$ 21,238	$ 19,574