Marketable Securities (Summary of available-for-sale securities ) (Details) - USD ($)	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Increase (Decrease) in Notes Payable, Related Parties	$ 10,000,000	$ 6,000,000
Proceeds from Sale and Maturity of Marketable Securities	6,000,000
Available-for-sale Securities, Short-term Investments, Amortized Cost		5,938,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	1,859,000	2,050,000
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	1,285,000	0
Aggregate fair value	3,144,000	2,050,000
Equity securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	7,149,000	7,475,000
Gross Unrealized Gains	588,000	248,000
Gross Unrealized Losses	64,000	37,000
Estimated Fair Value	7,673,000	7,686,000
Securities in a continuous loss position for less than 12 months	26,000	37,000
Securities in a continuous loss position for more than 12 months	38,000	0
Unrealized losses	$ 64,000	37,000
Proceeds for CMIC Loan [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross Realized Gain (Loss)		62,000
Maximum [Member]
Schedule of Available-for-sale Securities [Line Items]
Increase (Decrease) in Notes Payable, Related Parties		$ 10,000,000