Unaudited Quarterly Financial Data (Details) (USD $)	3 Months Ended								12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Unaudited Quarterly Financial Data [Abstract]
Net sales	$ 83,904,000	$ 83,992,000	$ 70,840,000	$ 62,975,000	$ 76,682,000	$ 65,568,000	$ 66,174,000	$ 50,245,000	$ 301,711,000	$ 258,669,000	$ 213,151,000
Cost of goods sold	62,995,000	59,564,000	52,420,000	45,159,000	52,761,000	43,642,000	46,469,000	34,231,000	220,138,000	177,103,000	143,810,000
Gross profit	20,909,000	24,428,000	18,420,000	17,816,000	23,921,000	21,926,000	19,705,000	16,014,000	81,573,000	81,566,000	69,341,000
Operating expenses [Abstract]
General and administrative	10,031,000	12,628,000	9,812,000	5,392,000	11,766,000	9,580,000	8,706,000	9,632,000	37,863,000	39,684,000	25,807,000
Sales and marketing	1,907,000	2,281,000	1,837,000	1,826,000	2,059,000	1,905,000	2,143,000	1,731,000	7,851,000	7,838,000	7,290,000
Research and development	611,000	601,000	539,000	522,000	541,000	452,000	398,000	549,000	2,273,000	1,940,000	1,930,000
Total operating expenses	12,549,000	15,510,000	12,188,000	7,740,000	14,366,000	11,937,000	11,247,000	11,912,000	47,987,000	49,462,000	35,027,000
Operating income	8,360,000	8,918,000	6,232,000	10,076,000	9,555,000	9,989,000	8,458,000	4,102,000	33,586,000	32,104,000	34,314,000
Other expense [Abstract]
Interest expense, net	3,148,000	3,165,000	3,339,000	3,413,000	3,177,000	6,524,000	4,663,000	3,925,000	13,065,000	18,289,000	12,324,000
Income from continuing operations before income tax expense	5,212,000	5,753,000	2,893,000	6,663,000	6,378,000	3,465,000	3,795,000	177,000	20,521,000	13,815,000	21,990,000
Income tax expense	2,110,000	2,826,000	1,418,000	2,714,000	3,311,000	2,317,000	1,631,000	74,000	9,068,000	7,333,000	7,432,000
Income from continuing operations					3,067,000	1,148,000	2,164,000	103,000	11,453,000	6,482,000	14,558,000
Income from discontinued operations					0	0	0	100,877,000	0	100,877,000	(106,069,000)
Net income (loss)	$ 3,102,000	$ 2,927,000	$ 1,475,000	$ 3,949,000	$ 3,067,000	$ 1,148,000	$ 2,164,000	$ 100,980,000	$ 11,453,000	$ 107,359,000	$ (91,511,000)
Basic net income per share from continuing operations (in dollars per share)					$ 0.20	$ 0.08	$ 0.15	$ 0.01	$ 0.68	$ 0.45	$ 1.01
Basic net income per share from discontinued operations (in dollars per share)					$ 0	$ 0	$ 0	$ 6.97	$ 0	$ 6.89	$ (7.40)
Basic net income (loss) per share (in dollars per share)	$ 0.17	$ 0.16	$ 0.09	$ 0.26	$ 0.20	$ 0.08	$ 0.15	$ 6.98	$ 0.68	$ 7.34	$ (6.39)
Diluted net income per share from continuing operations (in dollars per share)					$ 0.19	$ 0.07	$ 0.15	$ 0.01	$ 0.65	$ 0.42	$ 1.01
Diluted net income per share from discontinued operation (in dollars per share)					$ 0	$ 0	$ 0	$ 6.90	$ 0	$ 6.59	$ (7.37)
Diluted net income (loss) per share (in dollars per share)	$ 0.16	$ 0.16	$ 0.09	$ 0.25	$ 0.19	$ 0.07	$ 0.15	$ 6.91	$ 0.65	$ 7.01	$ (6.36)