Revenue Recognition, Consolidated Statement of Operations (Details) - USD ($)	3 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Mar. 31, 2018	Mar. 31, 2017
Consolidated Statement of Operations [Abstract]
Net sales	$ 92,565,000	$ 95,519,000
Cost of goods sold	75,314,000	68,843,000
Gross profit	17,251,000	26,676,000
Operating expenses [Abstract]
General and administrative	12,340,000	6,187,000
Sales and marketing	4,392,000	3,394,000
Research and development	1,736,000	1,002,000
Total operating expenses	18,468,000	10,583,000
Operating (loss) income	(1,217,000)	16,093,000
Interest expense, net	5,075,000	3,314,000
(Loss) income before income tax (benefit) expense	(6,292,000)	12,779,000
Income tax expense	(1,278,000)	4,628,000
Net (loss) income	$ (5,014,000)	$ 8,151,000
Basic net income per share (in dollars per share)	$ (0.27)	$ 0.44
Diluted net income per share (in dollars per share)	$ (0.27)	$ 0.42
As Previously Reported [Member] | ASC 606 [Member]
Consolidated Statement of Operations [Abstract]
Net sales		$ 95,063,000
Cost of goods sold		69,224,000
Gross profit		25,839,000
Operating expenses [Abstract]
General and administrative		6,187,000
Sales and marketing		3,394,000
Research and development		1,002,000
Total operating expenses		10,583,000
Operating (loss) income		15,256,000
Interest expense, net		3,314,000
(Loss) income before income tax (benefit) expense		11,942,000
Income tax expense		4,316,000
Net (loss) income		$ 7,626,000
Basic net income per share (in dollars per share)		$ 0.41
Diluted net income per share (in dollars per share)		$ 0.39
Adoption of ASU 2014-09 [Member] | ASC 606 [Member]
Consolidated Statement of Operations [Abstract]
Net sales		$ 456,000	$ 557,000	$ (824,000)
Cost of goods sold		(381,000)	$ 66,000	$ (758,000)
Gross profit		837,000
Operating expenses [Abstract]
General and administrative		0
Sales and marketing		0
Research and development		0
Total operating expenses		0
Operating (loss) income		837,000
Interest expense, net		0
(Loss) income before income tax (benefit) expense		837,000
Income tax expense		312,000
Net (loss) income		$ 525,000
Basic net income per share (in dollars per share)		$ 0.03
Diluted net income per share (in dollars per share)		$ 0.03