Note 13 - Net Loss Per Share Available to Common Stockholders (Tables)

12 Months Ended

Dec. 31, 2018

Notes Tables

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

	Years Ended December 31,
	2018			2017			2016
Numerator:
Net loss available to common stockholders	$	(41,244	)	$	(31,491	)	$	(16,480	)
Denominator:
Weighted average number of shares, basic and diluted		5,783			5,638			5,474
Net loss per share available to common stockholders:
Basic and diluted net loss per common share available to common stockholders	$	(7.13	)	$	(5.59	)	$	(3.01	)

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

	Years Ended December 31,
	2018		2017		2016
Options to purchase common stock		436		436		536
RSUs		834		568		429
Common stock subject to repurchase		—		—		1
Total		1,270		1,004		966