Option Activity and Changes (Detail) (USD $)	9 Months Ended
	Sep. 28, 2013
Shares
Options outstanding at December 31, 2012	3,128,408
Options granted	902,770
Options cancelled and forfeited	(1,339,934)
Options exercised	(69,838)
Options outstanding at September 28, 2013	2,621,406
Vested and expected to vest at September 28, 2013	2,386,932
Options exercisable at September 28, 2013	1,412,001
Weighted Average Exercise Price
Options outstanding at December 31, 2012	$ 11.52
Options granted	$ 5.59
Options cancelled and forfeited	$ 13.73
Options exercised	$ 3.91
Options outstanding at September 28, 2013	$ 8.55
Vested and expected to vest at September 28, 2013	$ 8.77
Options exercisable at September 28, 2013	$ 10.34