Note 10 - Stock Based Compensation (Detail) - Summary of Stock Option Awards and Changes (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Options Outstanding - Number Outstanding (in Shares)	3,264,880	3,113,144	2,167,646	1,641,979
Options Outstanding - Weighted Average Remaining Contractual Term (in years)	6 years 255 days
Options Outstanding - Weighted Average Exercise Price	$ 3.25	$ 3.75	$ 3.96	$ 3.96
Options Exercisable - Number Outstanding (in Shares)	1,910,025
Options Exercisable - Weighted Average Remaining Contractual Term (in years)	5 years 146 days
Range One (Member)
Range of Exercise Price - Lower Limit	$ 1.00
Range of Exercise Price - Upper Limit	$ 3.00
Options Outstanding - Number Outstanding (in Shares)	2,279,918
Options Outstanding - Weighted Average Remaining Contractual Term (in years)	7 years 109 days
Options Outstanding - Weighted Average Exercise Price	$ 2.47
Options Exercisable - Number Outstanding (in Shares)	1,108,562
Options Exercisable - Weighted Average Remaining Contractual Term (in years)	5 years 328 days
Options Exercisable - Weighted Average Exercise Price	$ 2.59
Range Two (Member)
Range of Exercise Price - Lower Limit	$ 3.01
Range of Exercise Price - Upper Limit	$ 5.00
Options Outstanding - Number Outstanding (in Shares)	547,704
Options Outstanding - Weighted Average Remaining Contractual Term (in years)	6 years 109 days
Options Outstanding - Weighted Average Exercise Price	$ 3.85
Options Exercisable - Number Outstanding (in Shares)	364,205
Options Exercisable - Weighted Average Remaining Contractual Term (in years)	5 years 109 days
Options Exercisable - Weighted Average Exercise Price	$ 3.93
Range Three (Member)
Range of Exercise Price - Lower Limit	$ 5.01
Range of Exercise Price - Upper Limit	$ 7.00
Options Outstanding - Number Outstanding (in Shares)	388,631
Options Outstanding - Weighted Average Remaining Contractual Term (in years)	4 years 146 days
Options Outstanding - Weighted Average Exercise Price	$ 5.77
Options Exercisable - Number Outstanding (in Shares)	388,631
Options Exercisable - Weighted Average Remaining Contractual Term (in years)	4 years 146 days
Options Exercisable - Weighted Average Exercise Price	$ 5.77
Range Four (Member)
Range of Exercise Price - Lower Limit	$ 7.01
Range of Exercise Price - Upper Limit	$ 10.00
Options Outstanding - Number Outstanding (in Shares)	22,167
Options Outstanding - Weighted Average Remaining Contractual Term (in years)	2 years
Options Outstanding - Weighted Average Exercise Price	$ 8.06
Options Exercisable - Number Outstanding (in Shares)	22,167
Options Exercisable - Weighted Average Remaining Contractual Term (in years)	2 years
Options Exercisable - Weighted Average Exercise Price	$ 8.06
Range Five (Member)
Options Outstanding - Number Outstanding (in Shares)	26,460
Options Outstanding - Weighted Average Remaining Contractual Term (in years)	1 year 73 days
Options Outstanding - Weighted Average Exercise Price	$ 17.04
Options Exercisable - Number Outstanding (in Shares)	26,460
Options Exercisable - Weighted Average Remaining Contractual Term (in years)	1 year 73 days
Options Exercisable - Weighted Average Exercise Price	$ 17.04