Intangible Assets and Debt Issuance Costs (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Acquired Intangible Assets by Major Class [Line Items]
Intangible assets, gross carrying amount	$ 184,472	$ 180,294
Intangible assets, accumulated amortization	(118,232)	(109,317)
Intangible assets, net amount	66,240	70,977
Unamortized Intangible Assets (Trademarks), Weighted Useful Lives	0
Trademarks, net	2,308	2,308	[1]
Amortized Intangible Assets, Gross Carrying Amount	173,762	173,762
Amortized Intangible Assets, Accumulated Amortization	(114,108)	(106,708)
Amortized Intangible Assets, Net Amount	59,654	67,054	[1]
Licenses
Acquired Intangible Assets by Major Class [Line Items]
Weighted Useful Lives (Years)	4 years 11 months 16 days
Amortized Intangible Assets, Gross Carrying Amount	91,488	91,488
Amortized Intangible Assets, Accumulated Amortization	(81,691)	(77,844)
Amortized Intangible Assets, Net Amount	9,797	13,644
Product lines
Acquired Intangible Assets by Major Class [Line Items]
Weighted Useful Lives (Years)	5 years 10 months 2 days
Amortized Intangible Assets, Gross Carrying Amount	66,594	66,594
Amortized Intangible Assets, Accumulated Amortization	(21,496)	(19,561)
Amortized Intangible Assets, Net Amount	45,098	47,033
Customer relationships
Acquired Intangible Assets by Major Class [Line Items]
Weighted Useful Lives (Years)	5 years 2 months 16 days
Amortized Intangible Assets, Gross Carrying Amount	9,347	9,347
Amortized Intangible Assets, Accumulated Amortization	(7,041)	(5,903)
Amortized Intangible Assets, Net Amount	2,306	3,444
Trade Name
Acquired Intangible Assets by Major Class [Line Items]
Weighted Useful Lives (Years)	5 years
Amortized Intangible Assets, Gross Carrying Amount	3,000	3,000
Amortized Intangible Assets, Accumulated Amortization	(700)	(250)
Amortized Intangible Assets, Net Amount	2,300	2,750
Non-compete/Employment contracts
Acquired Intangible Assets by Major Class [Line Items]
Weighted Useful Lives (Years)	3 years 10 months 24 days
Amortized Intangible Assets, Gross Carrying Amount	3,333	3,333
Amortized Intangible Assets, Accumulated Amortization	(3,180)	(3,150)
Amortized Intangible Assets, Net Amount	153	183
4.50% Convertible senior notes
Acquired Intangible Assets by Major Class [Line Items]
Deferred Costs, Weighted Useful Lives (Years)	5 years 18 days
Deferred Costs, Gross Carrying Amount	8,402	4,224
Deferred Costs, Accumulated Amortization	(4,124)	(2,609)
Deferred Costs, Net Amount	$ 4,278	$ 1,615

[1] Derived from audited financial statements