Stock Options - Summary of activity of stock options (Details) (USD $)	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Shares outstanding, beginning	83,750	53,750	107,500
Number of shares granted		40,000	42,500
Number of shares exercised	(3,750)	(10,000)	(85,250)
Shares forfeited or expired			(11,000)
Shares outstanding, end	80,000	83,750	53,750
Options Vested	30,000
Options Exercisable	30,000
Options Outstanding, Weighted Average Exercise Price Per Share, beginning	$ 6.42	$ 5.69	$ 5.94
Options Outstanding, Weighted Average Exercise Price Per Share, end	$ 6.52	$ 6.42	$ 5.69
Options Outstanding, Weighted Aggregate Average Remaining Contract Life in Years	8 years 237 days	7 years 121 days	2 years 186 days
Options Outstanding, Intrinsic Value, beginning	$ 127,363	$ 401,200	$ 237,088
Options Outstanding, Intrinsic Value, end		127,363	401,200
Options Granted, Weighted Average Exercise Price Per Share		$ 6.80	$ 6.24
Options Exercised, Weighted Average Exercise Price Per Share	$ 4.35	$ 4.00	$ 6.26
Options Forfeited or Expired, Weighted Average Exercise Price Per Share			$ 5.89
Options Vested, Weighted Average Exercise Price Per Share	$ 6.42
Options Vested, Weighted Aggregate Average Remaining Contract Life in Years	7 years 299 days
Options Vested, Intrinsic Value
Options Exercisable, Weighted Average Exercise Price Per Share	$ 6.42
Options Exercisable, Weighted Aggregate Average Remaining Contract Life in Years	7 years 299 days
Options Exercisable, Intrinsic Value