Restructuring - Additional Information (Detail)	1 Months Ended	12 Months Ended
Nov. 30, 2012 Position	Dec. 31, 2011 Position
Restructuring and Related Activities [Abstract]
Reduction in workforce, number of employees	21	35

The number of positions eliminated during the period as a result of restructuring activities.

No definition available.

Name:	us-gaap_RestructuringAndRelatedCostNumberOfPositionsEliminated
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration