Note 10 - Fair Value Measurements - Black -Scholes Model and Assumptions (Details)	6 Months Ended
	Jun. 30, 2017 $ / shares
Stock price (in dollars per share)	$ 2.33
Exercise price (in dollars per share)	$ 2.22
Expected term (in years) (Year)	4 years 273 days
Risk-free interest rate	1.90%
Expected volatility	110.00%