Shareholders' Equity - Summary of Stock Option Plan Activity and Shares Available for Granting of Options (Detail)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2011 Stock Option Plan 1985	Dec. 31, 2010 Stock Option Plan 1985	Dec. 31, 2009 Stock Option Plan 1985	Dec. 31, 2009 Stock Option Plan 2008	Dec. 31, 2010 Stock Option Plan 2009	Dec. 31, 2009 Stock Option Plan 2009	Dec. 31, 2011 Stock Option Plan 2010	Dec. 31, 2010 Stock Option Plan 2010	Dec. 31, 2011 Stock Option Plan 2011	May 04, 2011 Stock Option Plan 2011
Shares Available for Grant of Options [Roll Forward]
Beginning Balance		6,912	6,912	6,912	911,585	550,800		365,115
Options authorized							3,000,000		3,000,000	3,000,000	3,000,000
Options granted	(2,998,390)	0	0	0	0	0	(2,449,200)	0	(2,634,885)	(2,998,390)
Options not granted					(911,585)	(550,800)		(365,115)
Ending Balance		6,912	6,912	6,912	0	0	550,800	0	365,115	1,610