Note 7 - Fair Value Measurements (Detail) - Financial assets measured at fair value on a recurring basis: (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Acquisition-related contingent consideration [Member] | Financial Liabilities [Member] | Fair Value, Inputs, Level 3 [Member]
Financial Liabilities			$ (475)	[1]
Acquisition-related contingent consideration [Member] | Financial Liabilities [Member]
Financial Liabilities			(475)	[1]
Acquisition-related contingent consideration [Member] | Fair Value, Inputs, Level 3 [Member]
Financial Liabilities	(475)	[1]
Acquisition-related contingent consideration [Member]
Financial Liabilities	(475)	[1]
Financial Assets [Member] | Fair Value, Inputs, Level 1 [Member]
Financial Assets	171,588		199,679
Financial Assets [Member] | Fair Value, Inputs, Level 2 [Member]
Financial Assets	54,756		69,222
Financial Assets [Member] | Fair Value, Inputs, Level 3 [Member]
Financial Assets	22,746		2,804
Financial Assets [Member]
Financial Assets	249,090		271,705
Cash, including short-term deposits [Member] | Fair Value, Inputs, Level 1 [Member]
Financial Assets	60,581	[2]	80,085	[2]
Cash, including short-term deposits [Member]
Financial Assets	60,581	[2]	80,085	[2]
US Treasury and Government [Member] | Fair Value, Inputs, Level 1 [Member]
Financial Assets	78,476	[3]	99,477	[3]
US Treasury and Government [Member]
Financial Assets	78,476	[3]	99,477	[3]
Corporate Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Financial Assets	32,531	[3]	20,117	[3]
Corporate Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Financial Assets	6	[3]
Corporate Securities [Member]
Financial Assets	32,537	[3]	20,117	[3]
Commercial Paper [Member] | Fair Value, Inputs, Level 2 [Member]
Financial Assets	21,546	[3]	22,291	[3]
Commercial Paper [Member]
Financial Assets	21,546	[3]	22,291	[3]
Corporate Obligations [Member] | Fair Value, Inputs, Level 2 [Member]
Financial Assets	33,210	[3]	46,931	[3]
Corporate Obligations [Member] | Fair Value, Inputs, Level 3 [Member]
Financial Assets	21,719	[3]	1,783	[3]
Corporate Obligations [Member]
Financial Assets	54,929	[3]	48,714	[3]
Non-controlling interests in certain funds [Member] | Fair Value, Inputs, Level 3 [Member]
Financial Assets	1,021	[4]	1,021	[4]
Non-controlling interests in certain funds [Member]
Financial Assets	$ 1,021	[4]	$ 1,021	[4]

[1] Recorded within "Other long-term liabilities."

[2] At March 31, 2013, the Company recorded $47.5 million and $13.1 million within "Cash and cash equivalents" and "Marketable securities," respectively.

[3] Recorded within "Marketable securities."

[4] Recorded within "Other long-term assets."