Note 9 - Stock-based Compensation - Allocation of Share-based Compensation Expense (Details) - Restricted Stock [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Allocated Share-based Compensation Expense	$ 98	$ 139	$ 186	$ 178
Cost of Sales [Member]
Allocated Share-based Compensation Expense	1	2	4	5
Selling and Marketing Expense [Member]
Allocated Share-based Compensation Expense		2		3
Research and Development Expense [Member]
Allocated Share-based Compensation Expense	1	3	4	5
General and Administrative Expense [Member]
Allocated Share-based Compensation Expense	$ 96	$ 132	$ 178	$ 165