Note 7 - Exercise Price Range Relating to Oustanding and Exercisable Options (Details) (USD $)	3 Months Ended
	Mar. 31, 2015
Range 1 (in shares)	3,370,592
Range 1	8 years 29 days
Range 1 (in dollars per share)	$ 6.30
Range 3 (in shares)	1,145,063
Range 3 (in dollars per share)	$ 12.74
Range One [Member]
Range 1 (in dollars per share)	$ 2.20
Range 1 (in dollars per share)	$ 2.40
Range 1 (in shares)	195,000
Range 1	9 years 222 days
Range 1 (in dollars per share)	$ 2.33
Range Two [Member]
Range 1 (in dollars per share)	$ 2.45
Range 1 (in dollars per share)	$ 2.45
Range 1 (in shares)	1,035,000
Range 1	9 years 182 days
Range 1 (in dollars per share)	$ 2.45
Range Three [Member]
Range 1 (in dollars per share)	$ 2.47
Range 1 (in dollars per share)	$ 4.05
Range 1 (in shares)	605,000
Range 1	8 years 299 days
Range 1 (in dollars per share)	$ 3.18
Range 3 (in shares)	86,250
Range 3 (in dollars per share)	$ 3.96
Range 4 [Member]
Range 1 (in dollars per share)	$ 4.07
Range 1 (in dollars per share)	$ 75.81
Range 1 (in shares)	1,535,592
Range 1	6 years 156 days
Range 1 (in dollars per share)	$ 10.62
Range 3 (in shares)	1,058,813
Range 3 (in dollars per share)	$ 13.45