Consolidated Statements of Stockholders' Equity (USD $)	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Balance at Mar. 31, 2013	$ 611,571	$ 6,321,411	$ 21,191,237		$ 28,124,219
Balance (in shares) at Mar. 31, 2013	2,446,286
Net income			1,466,636		1,466,636
Unrealized loss from marketable securities, net of tax				(7,780)	(7,780)
Cash dividend ($0.30 per share)			(733,885)		(733,885)
Exercise of stock options (in shares)	2,500				2,500
Exercise of stock options	625	24,750			25,375
Repurchase of stock options		(394,490)			(394,490)
Repurchase of common stock (in shares)	(93,758)
Repurchase of common stock	(23,440)	(1,054,776)			(1,078,216)
Tax effect from exercise, forfeiture and repurchase of stock options		(65,000)			(65,000)
Compensation expense related to stock options		23,198			23,198
Balance at Mar. 31, 2014	588,756	4,855,093	21,923,988	(7,780)	27,360,057
Balance (in shares) at Mar. 31, 2014	2,355,027
Net income			2,483,926		2,483,926
Unrealized loss from marketable securities, net of tax				(127,133)	(127,133)
Exercise of stock options (in shares)	17,500				17,500
Exercise of stock options	4,375	146,375			150,750
Repurchase of stock options		(130,335)			(130,335)
Tax effect from exercise, forfeiture and repurchase of stock options		49,000			49,000
Compensation expense related to stock options		8,958			8,958
Balance at Mar. 31, 2015	$ 593,131	$ 4,929,090	$ 24,407,915	$ (134,913)	$ 29,795,223
Balance (in shares) at Mar. 31, 2015	2,372,527