Summary of Operations by Geographic Area (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Segment Reporting Information [Line Items]
Net sales to external customers	$ 20,674	$ 34,484	$ 34,115	$ 24,248	$ 18,694	$ 31,586	$ 33,218	$ 24,697	$ 113,521	$ 108,195	$ 108,600
Operating income (loss)									(2,133)	(544)	1,285
Assets	49,659				47,736				49,659	47,736
USA
Segment Reporting Information [Line Items]
Net sales to external customers									85,374	81,856	80,890
Operating income (loss)									(459)	7	206
Assets	38,341				35,317				38,341	35,317	34,175
Canada
Segment Reporting Information [Line Items]
Net sales to external customers									28,147	26,339	27,710
Operating income (loss)									(1,607)	(582)	769
Assets	11,009				11,630				11,009	11,630	12,742
Other Countries
Segment Reporting Information [Line Items]
Net sales to external customers
Operating income (loss)									(67)	31	310
Assets	$ 309				$ 789				$ 309	$ 789	$ 865