Property, Plant, Equipment and Rental Assets - Tabular Disclosure (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Mar. 31, 2020
Property, Plant and Equipment
Total property, plant and equipment, gross	$ 33,259	$ 32,059
Less: accumulated depreciation	(25,184)	(24,310)
Total property, plant, equipment and rental assets, net	8,075	7,749
Machinery, equipment, automobiles and furniture
Property, Plant and Equipment
Total property, plant and equipment, gross	15,243	15,115
Leasehold improvements
Property, Plant and Equipment
Total property, plant and equipment, gross	8,044	7,857
Molds and tooling
Property, Plant and Equipment
Total property, plant and equipment, gross	3,132	3,101
Rental assets
Property, Plant and Equipment
Total property, plant and equipment, gross	$ 6,840	$ 5,986