Restructuring and Excess Facilities - Additional Information (Detail) (USD $)	12 Months Ended							3 Months Ended		12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2008 Sunnyvale building [Member]	Dec. 31, 2008 Buildings in United Kingdom [Member]	Dec. 31, 2008 Selling, general and administrative expenses [Member] Sunnyvale building [Member]	Dec. 31, 2008 Selling, general and administrative expenses [Member] Buildings in United Kingdom [Member]	Mar. 31, 2011 Excess Facilities [Member]	Dec. 31, 2010 Excess Facilities [Member]	Dec. 31, 2012 Excess Facilities [Member]	Dec. 31, 2011 Excess Facilities [Member]	Dec. 31, 2010 Excess Facilities [Member]	Dec. 31, 2010 Scopus Facilities [Member]	Dec. 31, 2009 Scopus Facilities [Member]	Dec. 31, 2009 Scopus Facilities [Member] Cost of revenue [Member]	Dec. 31, 2009 Scopus Facilities [Member] Severance and other expenses [Member]	Dec. 31, 2009 Scopus Facilities [Member] Provisions for excess and obsolete inventories [Member]
Restructuring Cost and Reserve [Line Items]
Expected sublease income						$ 1,200,000	$ 200,000
Lease terminated				2010-09	2010-10
Excess facilities expense	(94,000)	(517,000)	(2,991,000)					517,000	3,061,000	(94,000)	(517,000)	(3,061,000)	(3,000)	8,300,000	6,300,000	500,000	5,800,000
Severance costs														$ 2,000,000