Note 6 - Derivative Instruments and Hedging Activities (Details) - Effects of Derivative Instruments on Income and Other Comprehensive Income (OCI) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Operating Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	$ (269,645)	$ (200,756)	$ (571,235)	$ (506,138)
Cost of Sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in OCI on Derivative (Effective Portion)	333,909	430,277	(210,883)	214,810
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	(102,310)	$ (31,457)	(216,794)	$ (72,101)
Amount of Gain or (Loss) Recognized in Income on Derivative (ineffective Portion and Amount Excluded from Effectiveness Testing)	$ (8,741)		$ (31,323)