Note 3 - Accounting Policies (Details Textual) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Inventory, Net	$ 4,641		$ 5,340
Inventory, Raw Materials, Net of Reserves	1,600
Inventory, Finished Goods, Net of Reserves	3,000
Cost of Goods Sold	1,186
Deferred Revenue, Current	5,235		$ 1,099
Asset Impairment Charges	0	0
Available-for-sale Securities, Gross Realized Gains	0	0
Available-for-sale Securities, Gross Realized Losses	0	$ 0
Accounting Standards Update 2016-09 [Member]
Deferred Tax Assets, Gross	3,600
Deferred Tax Assets, Valuation Allowance	3,600
Cost of Sales [Member]
Inventory Write-down	900
SUSTOL [Member]
Cost of Goods Sold	$ 300