Note 3 - Marketable Securities (Details Textual) - USD ($)	12 Months Ended
	Mar. 31, 2016		Mar. 31, 2015
Marketable Securities	$ 9,656,000		$ 5,279,000
Available-for-sale Securities, Amortized Cost Basis	9,791,000		5,490,000
Available-for-sale Securities, Gross Unrealized Gain	422,000		0
Available-for-sale Securities, Gross Unrealized Loss	557,000		211,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	5,903,000		4,168,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	163,000		176,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	4,711,000		1,111,000
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	395,000		35,000
Marketable Securities, Realized Gain (Loss), Excluding Other than Temporary Impairments	$ 49,720	[1]	$ 8,487

[1] The Consolidated Statement of Cash Flow for the year ended March 31, 2016 has been restated. See Note 1A.