Note 11 - Long-term Incentive Plan - Stock Option Activity (Details)	6 Months Ended
	Jun. 30, 2018 $ / shares shares
Options outstanding (in shares) | shares	760,000
Weighted average exercise price, options outstanding (in dollars per share)	$ 2.51
Weighted average fair value at grant date, options outstanding (in dollars per share)	$ 1
Options granted (in shares) | shares
Weighted average exercise price, options granted (in dollars per share)
Weighted average fair value at grant date, options granted (in dollars per share)
Options exercised (in shares) | shares
Weighted average exercise price, options exercised (in dollars per share)
Options cancelled or forfeited (in shares) | shares
Weighted average exercise price, options cancelled or forfeited (in dollars per share)
Weighted average fair value at grant date, options cancelled or forfeited (in dollars per share)
Options outstanding (in shares) | shares	760,000
Weighted average exercise price, options outstanding (in dollars per share)	$ 2.51
Weighted average fair value at grant date, options outstanding (in dollars per share)	$ 1
Options vested (in shares) | shares	706,000
Options exercisable (in shares) | shares	286,000