Note 4 - Stockholders' Equity - Allocation of Recognized Period Costs (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]
Allocation of recognized period costs	$ 956	$ 914	$ 2,041	$ 1,801
Research and Development Expense [Member]
Allocation of recognized period costs	651	510	1,357	1,001
Selling, General and Administrative Expenses [Member]
Allocation of recognized period costs	684	931	1,559	1,752
Allocation of recognized period costs	$ 2,291	$ 2,355	$ 4,957	$ 4,554