Stock-based Compensation - Amended and Restated 2000 Employee Stock Purchase Plan - Additional Information (Detail) (ESPP [Member], USD $) Share data in Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 04, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in the number of shares available to be sold under the ESPP		2
Maximum value of shares employees can purchase	$ 25,000
Option price as percentage of fair market value	85.00%
Maximum offering period	27 months
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of employee contribution to plan from base salary	1.00%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of employee contribution to plan from base salary	10.00%