Note 5 - Stockholders' Deficit - Warrant Activity (Details) - $ / shares |
6 Months Ended | 12 Months Ended |
|---|---|---|
Dec. 31, 2017 |
Jun. 30, 2017 |
|
| Warrants outstanding and exercisable (in shares) | 2,342,590 | |
| Warrants outstanding and exercisable, weighted average exercise price (in dollars per share) | $ 1.97 | |
| Warrants outstanding and exercisable, remaining contractual term (Year) | 1 year 98 days | |
| Warrants issued (in shares) | ||
| Warrants issued, weighted average exercise price (in dollars per share) | ||
| Warrants forfeited (in shares) | (433,282) | |
| Warrants forfeited, weighted average exercise price (in dollars per share) | $ 2.20 | |
| Warrants outstanding and exercisable (in shares) | 1,909,308 | 2,342,590 |
| Warrants outstanding and exercisable, weighted average exercise price (in dollars per share) | $ 1.92 | $ 1.97 |
| Minimum [Member] | ||
| Warrants outstanding and exercisable, remaining contractual term (Year) | 43 days | |
| Maximum [Member] | ||
| Warrants outstanding and exercisable, remaining contractual term (Year) | 1 year 200 days |