Note 3 - Basis of Presentation and Summary of Significant Accounting Policies - Outstanding Dilutive Securities (Details) - shares	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Anti-dilutive securities (in shares)	14,214,066	2,700,455
Convertible Debt Securities [Member]
Anti-dilutive securities (in shares)	774,886	429,161
Series A Convertible Preferred Stock [Member]
Anti-dilutive securities (in shares)	10,449,338
Warrant [Member]
Anti-dilutive securities (in shares)	457,721	461,209
Employee Stock Option [Member]
Anti-dilutive securities (in shares)	2,525,989	1,797,812
Restricted Stock [Member]
Anti-dilutive securities (in shares)	6,132	12,273