Note 2 - Summary of Significant Accounting Policies (Detail) - Stock Option Activity (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012
Outstanding at December 31, 2011	7,371,304
Outstanding at December 31, 2011 (in Dollars per share)	$ 12.48
Outstanding at March 31, 2012	9,430,897
Outstanding at March 31, 2012 (in Dollars per share)	$ 11.64
Outstanding at March 31, 2012	8 years 9 months
Outstanding at March 31, 2012 (in Dollars)	$ 30,229
Exercisable at March 31, 2012	3,255,916
Exercisable at March 31, 2012 (in Dollars per share)	$ 8.37
Exercisable at March 31, 2012	7 years 10 months
Exercisable at March 31, 2012 (in Dollars)	$ 17,679
Options granted	2,314,976
Options granted (in Dollars per share)	$ 9.53
Options forfeited	(247,306)
Options forfeited (in Dollars per share)	$ 17.13
Options exercised	(8,077)
Options exercised (in Dollars per share)	$ 5.91