Reconciliation of Basic and Diluted Loss per Share (Detail) (USD $) In Thousands, except Per Share data, 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
Basic Loss
Net loss	$ (5,624)	$ (3,549)	$ (3,190)	$ 3,846	$ (1,652)	$ (3,800)	$ (2,765)	$ 2,019	$ (8,517)	$ (6,198)	$ (20,577)
Weighted average common shares outstanding									18,982	18,811	18,680
Basic loss per common share									$ (0.45)	$ (0.33)	$ (1.10)
Diluted Loss
Net loss	$ (5,624)	$ (3,549)	$ (3,190)	$ 3,846	$ (1,652)	$ (3,800)	$ (2,765)	$ 2,019	$ (8,517)	$ (6,198)	$ (20,577)
Weighted average common shares outstanding									18,982	18,811	18,680
Effect of dilutive securities
Weighted average common shares outstanding and potential dilutive shares									18,982	18,811	18,680
Diluted loss per share									$ (0.45)	$ (0.33)	$ (1.10)
Stock options
Effect of dilutive securities
Effect of dilutive securities
Restricted stock
Effect of dilutive securities
Effect of dilutive securities