Note 7 - Deferred Tax Assets and Liabilities (Details) - USD ($)	Mar. 31, 2016	Mar. 31, 2015
Vacation accrual	$ 118,611	$ 114,217
Inventory reserve	90,825	65,394
Depreciation and amortization	(30,174)	(63,631)
Stock-based compensation deductions	115,257	107,570
Unrealized gain on marketable securities	(257,545)	(425,922)
Other	14,214	28,716
Net deferred tax assets (liabilities)	$ 51,188
Net deferred tax assets (liabilities)		(173,656)
Deferred tax assets		$ 102,052
Long-term deferred tax assets	$ 51,188
Long-term deferred tax liabilities		$ (275,708)