Quarterly Results (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																12 Months Ended
	Jan. 31, 2017		Oct. 31, 2016		Jul. 31, 2016		Apr. 30, 2016		Jan. 31, 2016		Oct. 31, 2015		Jul. 31, 2015		Apr. 30, 2015		Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 23,441		$ 67,795		$ 61,354		$ 20,827		$ 19,494		$ 64,981		$ 61,072		$ 23,048		$ 173,417	$ 168,595	$ 164,052
Gross profit	6,431		24,311		23,738		8,063		4,210		23,210		23,996		8,194		62,543	59,610	55,398
Net income	$ (4,985)		$ 23,998		$ 6,885		$ (3,138)		$ (5,726)		$ 6,003		$ 7,450		$ (3,178)		$ 22,760	$ 4,549	$ 849
Per common share
Basic (dollar per share)	$ (0.33)	[1]	$ 1.59	[1]	$ 0.46	[1]	$ (0.21)	[1]	$ (0.38)	[1]	$ 0.40	[1]	$ 0.50	[1]	$ (0.21)	[1]	$ 1.51	$ 0.31	$ 0.06
Assuming dilution (dollar per share)	$ (0.33)	[1]	$ 1.57	[1]	$ 0.45	[1]	$ (0.21)	[1]	$ (0.38)	[1]	$ 0.39	[1]	$ 0.49	[1]	$ (0.21)	[1]	$ 1.49	$ 0.30	$ 0.06

[1] Net loss per share was calculated based on basic shares outstanding due to the anti-dilutive effect on the inclusion of common stock equivalent shares.