Property, Plant and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Mar. 31, 2016
Property, Plant and Equipment
Depreciation expense	$ 300	$ 300
Total property, plant and equipment, gross	31,554		$ 31,695
Less accumulated depreciation	(28,486)		(28,158)
Total property, plant and equipment, net	3,068		3,537
Machinery, rental equipment, equipment, automobiles and furniture
Property, Plant and Equipment
Total property, plant and equipment, gross	18,766		19,016
Leasehold improvements
Property, Plant and Equipment
Total property, plant and equipment, gross	9,855		9,855
Molds and tooling
Property, Plant and Equipment
Total property, plant and equipment, gross	$ 2,933		$ 2,824