Note 2 - Stock-Based Compensation (Detail) - 2004 Employee Stock Purchase Plan	3 Months Ended
Mar. 31, 2013
Available shares as of January 1, 2013	4,217,960
Additions to plan	713,466
Purchases	(65,247)
Available shares as of March 31, 2013	4,866,179

Number of shares of capital stock issued (purchased by employees) in connection with an employee stock ownership plan.

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

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