Note 10 - Stock Repurchase Program (Details Textual) - USD ($)	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016	Aug. 27, 2015	Jan. 21, 2009
Common Stock, Shares Authorized	6,000,000	6,000,000
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Capital Units, Authorized	10,000,000
Stock Repurchased and Retired During Period, Value			$ 2,311,673
Repurchase Program 2009 [Member]
Stock Repurchased and Retired During Period, Value	$ 0	$ 0	$ 1,695,788
Stock Repurchase Program, Authorized Amount					$ 2,500,000
Stock Repurchase Program Authorized Additional Amount				$ 5,000,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 4,540,806