Note 2 - Summary of Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2017

Notes Tables

Schedules of Concentration of Risk, by Risk Factor [Table Text Block]

Major distribution or collaboration partner	March 31 , 2017			March 31 , 2016
Distributer A		23	%		20	%
Distributer B		25	%		*
Distributer C		21	%		*
Collaborator		*			14	%

Major distribution partner	March 31 , 2017			December 31 , 2016
Distributer A		25	%		22	%
Distributer B		25	%		24	%
Distributer C		28	%		31	%

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

	Three Months Ended
	March 31,
(in thousands)	2017			2016
Net loss	$	(4,011	)	$	(5,077	)
Basic Shares		15,284			4,086
Add: shares issued upon assumed exercise of stock options and warrants		—			—
Diluted shares	$	15,284		$	4,086
Basic and diluted net loss per share	$	(0.26	)	$	(1.24	)

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

	Three Months Ended
	March 31,
(in thousands)	2017		2016
Period end stock options to purchase common stock		2,134		300
Period end common stock warrants		565		1,458
		2,699		1,758