Note 8 - Common Stock (Tables)

12 Months Ended

Dec. 31, 2016

Notes Tables

Common Stock Reserved for Future Issuance [Table Text Block]

	December 31,
	2016		2015
Stock-based compensation awards		2,982,470		2,419,901
Employee Stock Purchase Plan		292,821		297,359
Total		3,275,291		2,717,260