Note 9 - Common Stock (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

Common Stock Reserved for Future Issuance [Table Text Block]

	December 31,		December 31,
	2017		2016
Conversion of Series A Preferred Stock		22,112,775		-
Stock-based compensation awards		3,572,457		2,982,470
Employee Stock Purchase Plan		192,463		292,821
Total		25,877,695		3,275,291