Stock Incentive Plans - Summary of Activity of Stock Incentive and Equity Plans (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014
Shares available for grant
Shares available for grant, Beginning balance	2,240,103
Shares available for grant, Granted	(39,925)
Shares available for grant, Exercised
Shares available for grant, canceled/forfeited	28,626
Shares available for grant, Ending balance	2,228,804
Number of options outstanding
Number of options outstanding, Beginning balance	1,926,070
Number of options outstanding, Granted	12,000
Number of options outstanding, Exercised	(47,654)
Number of options outstanding, Canceled/forfeited	(28,645)
Number of options outstanding, Ending balance	1,861,771
Weighted - average option exercise price
Weighted - average option exercise price, Beginning balance	$ 12.46
Weighted - average option exercise price, Granted	$ 9.95
Weighted - average option exercise price, Exercised	$ 5.37
Weighted - average option exercise price, Canceled/forfeited	$ 17.35
Weighted - average option exercise price, Ending balance	$ 12.56
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	27,925
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	87,857
Restricted stock units [Member]
Number of restricted stock units outstanding
Number of restricted stock units outstanding, Beginning balance	45,941
Number of restricted stock units outstanding, Granted
Number of restricted stock units outstanding, Exercised
Number of restricted stock units outstanding, Canceled/forfeited
Number of restricted stock units outstanding, Ending balance	45,941