Summary of Basic and Diluted Earnings Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Earnings Per Share Basic And Diluted [Line Items]
Net income (loss)	$ (331)	$ 4,959	$ 1,459	$ 11,963
Weighted-average common shares outstanding	37,881	37,588	37,834	37,425
Earnings (loss) per share, basic	$ (0.01)	$ 0.13	$ 0.04	$ 0.32
Net income (loss)	$ (331)	$ 4,959	$ 1,459	$ 11,963
Weighted-average common shares outstanding, basic	37,881	37,588	37,834	37,425
Effect of assumed exercise of stock options, warrants and RSUs		1,342	1,063	1,439
Weighted-average common shares outstanding, diluted	37,881	38,930	38,897	38,864
Earnings (loss) per share, diluted	$ (0.01)	$ 0.13	$ 0.04	$ 0.31
Outstanding options and RSUs excluded as impact would be antidilutive	1,865	27	55	27
Stock Options
Earnings Per Share Basic And Diluted [Line Items]
Weighted-average effect of dilutive securities		1,078	817	1,187
RSUs
Earnings Per Share Basic And Diluted [Line Items]
Weighted-average effect of dilutive securities		261	246	249
Warrants
Earnings Per Share Basic And Diluted [Line Items]
Weighted-average effect of dilutive securities		3		3