Note 7 - Stock-based Compensation Expense by Department (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Cost of Sales [Member]
Allocated Share Based Compensation Expense	$ 40	$ 114	$ 181	$ 217
Selling and Marketing Expense [Member]
Allocated Share Based Compensation Expense	229	231	605	416
Research and Development Expense [Member]
Allocated Share Based Compensation Expense	105	180	285	362
General and Administrative Expense [Member]
Allocated Share Based Compensation Expense	376	457	1,011	948
Allocated Share Based Compensation Expense	$ 750	$ 982	$ 2,082	$ 1,943