Note 10 - Stock Options - Summary of the Status of Non-vested Shares (Details) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Balance, non-vested (in shares)	1,323,669	498,504
Balance, non-vested (in dollars per share)	$ 1.22	$ 1.05
Granted (in shares)	3,525,000	1,123,500
Granted (in dollars per share)	$ 0.28	$ 1.19
Vested (in shares)	(1,934,835)	(287,835)
Vested (in dollars per share)	$ 0.49	$ 0.83
Forfeited (in shares)	(1,254,000)	(10,500)
Forfeited (in dollars per share)	$ 0.56	$ 1.48
Balance, non-vested (in shares)	1,659,834	1,323,669
Balance, non-vested (in dollars per share)	$ 0.58	$ 1.22