Note 13 - Employee Equity Incentive Plans - Stock Options Outstanding (Details) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Low Price range (in dollars per share)	$ 0	$ 0
High Price range (in dollars per share)	$ 0.70	$ 0.70
Outstanding stock options (in shares)	1,225,000	2,002,500
Weighted average remaining contractual life - outstanding (Year)	2 years 226 days	1 year 146 days
Weighted average outstanding strike price - outstanding (in dollars per share)	$ 0.17	$ 0.14
Vested stock options (in shares)	737,500	1,752,500
Weighted average remaining contractual life - vested (Year)	1 year 138 days	1 year 7 days
Weighted average outstanding strike price - vested (in dollars per share)	$ 0.15	$ 0.13
Range One [Member]
Low Price range (in dollars per share)	0	0
High Price range (in dollars per share)	$ 0.20	$ 0.20
Outstanding stock options (in shares)	850,000	1,777,500
Weighted average remaining contractual life - outstanding (Year)	2 years 54 days	1 year 51 days
Weighted average outstanding strike price - outstanding (in dollars per share)	$ 0.15	$ 0.13
Vested stock options (in shares)	625,000	1,652,500
Weighted average remaining contractual life - vested (Year)	1 year 116 days	339 days
Weighted average outstanding strike price - vested (in dollars per share)	$ 0.14	$ 0.13
Range Two [Member]
Low Price range (in dollars per share)	0.21	0.21
High Price range (in dollars per share)	$ 0.29	$ 0.29
Outstanding stock options (in shares)	375,000	125,000
Weighted average remaining contractual life - outstanding (Year)	3 years 255 days	2 years 302 days
Weighted average outstanding strike price - outstanding (in dollars per share)	$ 0.23	$ 0.22
Vested stock options (in shares)	112,500	100,000
Weighted average remaining contractual life - vested (Year)	1 year 244 days	2 years 167 days
Weighted average outstanding strike price - vested (in dollars per share)	$ 0.21	$ 0.21
Range Three [Member]
Low Price range (in dollars per share)	0.30	0.30
High Price range (in dollars per share)	$ 0.49	$ 0.49
Outstanding stock options (in shares)	0	100,000
Weighted average remaining contractual life - outstanding (Year)	0 years	4 years 62 days
Weighted average outstanding strike price - outstanding (in dollars per share)	$ 0	$ 0.30
Vested stock options (in shares)	0	0
Weighted average remaining contractual life - vested (Year)	0 years	0 years
Weighted average outstanding strike price - vested (in dollars per share)	$ 0	$ 0
Range Four [Member]
Low Price range (in dollars per share)	0.50	0.50
High Price range (in dollars per share)	$ 0.70	$ 0.70
Outstanding stock options (in shares)	0	0
Weighted average remaining contractual life - outstanding (Year)	0 years	0 years
Weighted average outstanding strike price - outstanding (in dollars per share)	$ 0	$ 0
Vested stock options (in shares)	0	0
Weighted average remaining contractual life - vested (Year)	0 years	0 years
Weighted average outstanding strike price - vested (in dollars per share)	$ 0	$ 0