Summary of Basic and Diluted Earnings Per Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Earnings Per Share Basic And Diluted [Line Items]
Net income (loss)	$ (2,267)	$ 2,273	$ 1,790	$ 7,004
Weighted-average common shares outstanding	37,865	37,405	37,812	37,341
Earnings (loss) per share, basic	$ (0.06)	$ 0.06	$ 0.05	$ 0.19
Net income (loss)	$ (2,267)	$ 2,273	$ 1,790	$ 7,004
Weighted-average common shares outstanding, basic	37,865	37,405	37,812	37,341
Effect of assumed exercise of stock options, warrants and RSUs		1,446	1,119	1,487
Weighted-average common shares outstanding, diluted	37,865	38,851	38,931	38,828
Earnings (loss) per share, diluted	$ (0.06)	$ 0.06	$ 0.05	$ 0.18
Outstanding options and RSUs excluded as impact would be antidilutive	1,146	31	54	27
Stock Options
Earnings Per Share Basic And Diluted [Line Items]
Weighted-average effect of dilutive securities		1,201	849	1,241
RSUs
Earnings Per Share Basic And Diluted [Line Items]
Weighted-average effect of dilutive securities		242	269	242
Warrants
Earnings Per Share Basic And Diluted [Line Items]
Weighted-average effect of dilutive securities		3	1	4