Purchased Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Finite Lived Intangible Assets [Line Items]
Gross Assets	$ 52,005	$ 46,379
Accumulated Amortization	(35,696)	(32,166)
Net Assets	16,309	14,213
Technology and patents
Finite Lived Intangible Assets [Line Items]
Gross Assets	34,517	32,176
Accumulated Amortization	(25,176)	(22,869)
Net Assets	9,341	9,307
Customer relationships
Finite Lived Intangible Assets [Line Items]
Gross Assets	15,147	11,898
Accumulated Amortization	(9,314)	(8,148)
Net Assets	5,833	3,750
Leasehold interest
Finite Lived Intangible Assets [Line Items]
Gross Assets	1,391	1,355
Accumulated Amortization	(256)	(241)
Net Assets	1,135	1,114
Noncompete agreements
Finite Lived Intangible Assets [Line Items]
Gross Assets	950	950
Accumulated Amortization	(950)	(908)
Net Assets		$ 42