Unaudited Quarterly Financial Data - Schedule of Quarterly Financial Information (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended										12 Months Ended
	Mar. 31, 2014		Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013		Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 28,273	[1]	$ 22,628	$ 15,464	$ 19,568		$ 21,952	$ 20,170	$ 23,421	$ 14,413	$ 85,933	$ 79,956	$ 84,942
Gross profit	10,474	[1]	8,439	5,413	6,805		8,843	8,630	9,829	5,511	31,131	32,813	35,214
Operating income (loss)	4,416		2,725	(305)	2,253	[2]	2,878	2,987	3,555	(1,230)	9,089	8,190	7,022
Net income	$ 2,815		$ 1,670	$ (217)	$ 1,373		$ 1,156	$ 1,709	$ 2,039	$ (828)	$ 5,641	$ 4,076	$ 3,776
Basic earnings (loss) per share:	$ 0.29		$ 0.17	$ (0.02)	$ 0.14		$ 0.12	$ 0.18	$ 0.21	$ (0.09)	$ 0.58	$ 0.43	$ 0.40
Diluted earnings (loss) per share:	$ 0.29		$ 0.17	$ (0.02)	$ 0.14		$ 0.12	$ 0.18	$ 0.21	$ (0.09)	$ 0.58	$ 0.43	$ 0.39

[1] The Company terminated a distributor contract which resulted in sales returns of $1,538 and lowered gross profit by $1,033.

[2] Included in operating income is a non-recurring environmental benefit of $1,207. See Note 13.