Note 10 - Stock-based Compensation Plan - Allocation of Share-based Compensation Expense (Details) - Restricted Stock [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Allocation of Share-based Compensation Expense	$ 85	$ 242	$ 480	$ 638
Cost of Sales [Member]
Allocation of Share-based Compensation Expense
Selling and Marketing Expense [Member]
Allocation of Share-based Compensation Expense	3		9	4
Research and Development Expense [Member]
Allocation of Share-based Compensation Expense	10	11	31	26
General and Administrative Expense [Member]
Allocation of Share-based Compensation Expense	$ 72	$ 231	$ 440	$ 608