Note 5 - Net Income per Share (Details) - Schedule of Earnings Per Share, Basic and Diluted - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Basic net income per share computation:
Net income	$ 272,055	$ 199,466	$ 682,364	$ 478,532
Weighted-average common shares outstanding	3,255,887	3,256,887	3,255,887	3,256,887
Basic net income per share	$ 0.08	$ 0.06	$ 0.21	$ 0.15
Diluted net income per share computation
Net income	$ 272,055	$ 199,466	$ 682,364	$ 478,532
Less: Change in fair value of warrants	34,000	0	33,000	0
Diluted income	$ 238,055	$ 199,466	$ 649,364	$ 478,532
Weighted-average common shares outstanding	3,255,887	3,256,887	3,255,887	3,256,887
Incremental shares attributable to the assumed exercise of outstanding stock options and warrants	10,246	3,912	11,305	5,171
Total adjusted weighted-average shares	3,266,133	3,260,799	3,267,192	3,262,058
Diluted net income per share	$ 0.07	$ 0.06	$ 0.20	$ 0.15