Note 10 - Summary of Outstanding Stock Options by Price Range (Details)	12 Months Ended
	Dec. 31, 2015 $ / shares shares
Range One [Member]
Range of exercise prices minimum (in dollars per share)	$ 0.22
Range of exercise prices maximum (in dollars per share)	$ 1.93
Outstanding options (in Shares) (in shares) | shares	369
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	3 years 109 days
Outstanding options, weighted average exercise price (in dollars per share)	$ 1.87
Exercisable (in Shares) (in shares) | shares	348
Exercisable options, weighted average exercise price (in dollars per share)	$ 1.93
Range Two [Member]
Range of exercise prices minimum (in dollars per share)	2
Range of exercise prices maximum (in dollars per share)	$ 3.24
Outstanding options (in Shares) (in shares) | shares	258
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	5 years 182 days
Outstanding options, weighted average exercise price (in dollars per share)	$ 3.22
Exercisable (in Shares) (in shares) | shares	258
Exercisable options, weighted average exercise price (in dollars per share)	$ 3.22
Range Three [Member]
Range of exercise prices minimum (in dollars per share)	3.65
Range of exercise prices maximum (in dollars per share)	$ 8.79
Outstanding options (in Shares) (in shares) | shares	58
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	3 years 109 days
Outstanding options, weighted average exercise price (in dollars per share)	$ 6.12
Exercisable (in Shares) (in shares) | shares	58
Exercisable options, weighted average exercise price (in dollars per share)	$ 6.12
Range Four [Member]
Range of exercise prices minimum (in dollars per share)	8.84
Range of exercise prices maximum (in dollars per share)	$ 18.98
Outstanding options (in Shares) (in shares) | shares	262
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	328 days
Outstanding options, weighted average exercise price (in dollars per share)	$ 9.19
Exercisable (in Shares) (in shares) | shares	262
Exercisable options, weighted average exercise price (in dollars per share)	$ 9.19
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term	3 years 109 days