Deferred Tax Assets and Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Sep. 30, 2011
Deferred tax assets:
Net operating loss carryforward	$ 22,120	$ 9,373
Research credit carryforward	2,310	1,388
Capital loss carryforward	91	21
Investments	1,141	1,235
Accrued compensation	1,297	1,586
Share-based compensation	20,109	24,489
Deferred revenue	3,577	1,042
Accrued lease costs	1,774	2,526
Property and equipment	3,629	4,239
Other	14,183	5,988
Deferred Tax Assets, Gross, Total	70,231	51,887
Less valuation allowance	(5,425)	(3,422)
Deferred Tax Assets, Net of Valuation Allowance, Total	64,806	48,465
Deferred tax liabilities:
Intangible assets	(31,364)	(20,541)
Prepaid expense	(3,405)	(3,942)
Other	(1,019)	(1,040)
Deferred Tax Liabilities, Gross	(35,788)	(25,523)
Deferred tax assets, net	$ 29,018	$ 22,942