Property and Equipment (Components of Property and Equipment) (Details) - USD ($)	9 Months Ended
	Dec. 31, 2019	Mar. 31, 2019
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 17,335,000	$ 17,499,000
Less accumulated depreciation	9,333,000	7,952,000
Property and equipment, net before construction work in progress	8,002,000	9,547,000
Construction in process	86,000	283,000
Property and equipment, net	8,088,000	9,830,000
Network Sites and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	16,187,000	15,954,000
Property and equipment, net	$ 0
Network Sites and Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Estimated useful life	5 years
Network Sites and Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Estimated useful life	10 years
Furniture and Fixtures and Other Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 291,000	1,026,000
Furniture and Fixtures and Other Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Estimated useful life	2 years
Furniture and Fixtures and Other Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Estimated useful life	5 years
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 143,000	140,000
Computer Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Estimated useful life	5 years
Computer Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Estimated useful life	7 years
Computer Software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 480,000	28,000
Computer Software [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Estimated useful life	1 year
Computer Software [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Estimated useful life	7 years
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Estimated useful life	10 years
Property and equipment, gross	$ 234,000	$ 351,000