Note 10 - Stock-based Compensation (Tables)

3 Months Ended

Mar. 31, 2018

Notes Tables

Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block]

	Three Months Ended March 31,
	2018		2017
Stock options and employee stock purchase plan awards
Research and development	$	9	$	9
Selling, general and administrative		30		30
Restricted stock awards
Research and development		—		12
Selling, general and administrative		—		17
Restricted stock units
Research and development		17		18
Selling, general and administrative		41		42
Total stock-based compensation	$	97	$	128