Stock Incentive Plans - Summary of Activity of Stock Incentive and Equity Plans (Detail) (USD $)	9 Months Ended
	Sep. 30, 2013
Shares available for grant
Shares available for grant, Beginning balance	2,200,604
Shares available for grant, Granted	(109,472)
Shares available for grant, Exercised
Shares available for grant, Cancelled/forfeited	243,650
Shares available for grant, Ending balance	2,334,782
Number of options outstanding
Number of options outstanding, Beginning balance	2,117,110
Number of options outstanding, Granted	82,815
Number of options outstanding, Exercised	(27,931)
Number of options outstanding, Cancelled/forfeited	(247,613)
Number of options outstanding, Ending balance	1,924,381
Weighted - average option exercise price
Weighted - average option exercise price, Beginning balance	$ 13.32
Weighted - average option exercise price, Granted	$ 7.79
Weighted - average option exercise price, Exercised	$ 5.02
Weighted - average option exercise price, Cancelled/forfeited	$ 18.40
Weighted - average option exercise price, Ending balance	$ 12.50
Number of restricted stock and board shares issued
Number of restricted stock and board shares issued, Beginning balance	59,932
Number of restricted stock and board shares issued, Granted	26,657
Number of restricted stock and board shares issued, Exercised
Number of restricted stock and board shares issued, Canceled/forfeited
Number of restricted stock and board shares issued, Ending balance	86,589