Note 2 - Fair Value Measurements (Detail) - Unrealized Gains And Losses On Investments (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Money Market Funds	$ 15,959	$ 51,066
US Treasuries and US Government Agency Bonds	14,121	25,281
Auction-rate securities backed by Student-Loan Notes	11,755	13,675	19,180
Total	25,876	38,956
Adjusted Cost [Member]
Money Market Funds	15,959	51,066
US Treasuries and US Government Agency Bonds	85,483	79,830
Auction-rate securities backed by Student-Loan Notes	12,245	14,305
Total	113,687	145,201
Unrealized Gain Or Loss [Member]
Money Market Funds	0	0
US Treasuries and US Government Agency Bonds	45	14
Total	45	14
Total Fair Value [Member]
US Treasuries and US Government Agency Bonds	(7)	(17)
Auction-rate securities backed by Student-Loan Notes	(490)	(630)
Total	(497)	(647)
Fair Value of Investments in Unrealized Loss Position [Member]
Money Market Funds	15,959	51,066
US Treasuries and US Government Agency Bonds	85,521	79,827
Auction-rate securities backed by Student-Loan Notes	11,755	13,675
Total	$ 113,235	$ 144,568

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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+ Details

- Definition

Amount of investment in debt and equity securities categorized neither as trading securities nor held-to-maturity securities and intended be sold or mature one year or operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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+ Details

- Definition

Investment in short-term money-market instruments (such as commercial paper, banker's acceptances, repurchase agreements, government securities, certificates of deposit, and so forth) which are highly liquid (that is, readily convertible to known amounts of cash) and so near their maturity that they present an insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify as cash equivalents by definition. Original maturity means an original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

+ References+ Details