Segment and Geographic Information - Reconciliation of Reportable Segment Operating Income and Segment Assets to Corresponding Consolidated Amounts (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2012
Income Reconciliation
Segment operating income (loss)	$ (2,699)		$ (16,798)		$ 1,642
Other unallocated corporate expenses	5,096	[1]	3,002	[1]	(1,833)	[1]
Amortization of acquired intangible assets	6,170		5,694		4,164
Impairment of acquired intangible assets	0		50		0
Restructuring and other charges	6,289		6,380		3,153
Pension settlement	0		0		8,937
In-process research and development	0		0		3,026
Operating income (loss)	(2,699)		(16,798)		1,642
Asset Reconciliation
Segment Assets	778,038		736,763
Cash, cash equivalents, restricted cash and marketable securities	245,456		173,539
Deferred tax assets	86,572		115,985
Assets held for sale	0		27,778
Equity method investments	28,944		25,687
Other unallocated corporate net assets	1,946		2,032
Total assets	778,038		736,763
Operating Segments, Total
Income Reconciliation
Segment operating income (loss)	14,856		(1,672)		19,089
Operating income (loss)	14,856		(1,672)		19,089
Asset Reconciliation
Segment Assets	415,120		391,742
Total assets	$ 415,120		$ 391,742

[1] Other unallocated corporate expenses for the fiscal year ended September 30, 2012 includes a credit of $3.3 million related to insurance proceeds received as reimbursement of litigation costs previously incurred.