Note 8 - Net Loss Per Share Attributable to Common Stockholders (Tables)

6 Months Ended

Jun. 30, 2017

Notes Tables

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]

	Three Months Ended June 30,				Six Months Ended June 30,
	2017		2016		2017		2016
Outstanding stock options		2,783,570		2,234,934		2,783,570		2,234,934
		2,783,570		2,234,934		2,783,570		2,234,934