Note 7 - Convertible Preferred Stock and Common Stock Warrants (Tables)

6 Months Ended

Jun. 30, 2017

Notes Tables

Schedule of Warrants Outstanding to Acquire Shares of Common Stock [Table Text Block]

	Outstanding		Range of exercise price per share
Common stock warrants issued prior to Merger		457,721		$20.00	-	$750.00
Common stock warrants issued in Series A		13,555,887			$2.22
		14,013,608