Stock-Based Compensation Expense Resulting From Stock Option Awards and ESPP (Detail) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 3,855	$ 3,867	$ 7,718	$ 7,741
Stock Options Plan | Cost of Revenues
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	30	55	56	115
Stock Options Plan | Selling, General and Administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	3,362	3,533	6,786	7,123
Restricted Stock Units | Selling, General and Administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	216	86	374	86
Employee Stock Purchase Plan | Selling, General and Administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 247	$ 193	$ 502	$ 417