Note 7 - Net Loss Per Common Share (Tables)

3 Months Ended

Mar. 31, 2018

Notes Tables

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

	Three Month Period Ended March 31,
	2018		2017
Basic and diluted weighted average common stock shares outstanding		14,098,610		12,964,639
Potentially dilutive securities excluded from loss per share computations:
Common stock options		3,326,841		3,387,581
Common stock purchase warrants		6,676,849		7,603,141
Restricted stock unvested		337,981		282,350