Stock Incentive Plans - Summary of Activity of Stock Incentive and Equity Plans (Detail) (USD $)	9 Months Ended
	Sep. 30, 2014
Shares available for grant
Shares available for grant, Beginning balance	2,240,103
Shares available for grant, Granted	(367,225)
Shares available for grant, Exercised	0
Shares available for grant, Cancelled/forfeited	196,719
Shares available for grant, Ending balance	2,069,597
Number of options outstanding
Number of options outstanding, Beginning balance	1,926,070
Number of options outstanding, Granted	339,300
Number of options outstanding, Exercised	(47,654)
Number of options outstanding, Cancelled/forfeited	(193,831)
Number of options outstanding, Ending balance	2,023,885
Weighted - average option exercise price
Weighted - average option exercise price, Beginning balance	$ 12.46
Weighted - average option exercise price, Granted	$ 5.49
Weighted - average option exercise price, Exercised	$ 5.37
Weighted - average option exercise price, Cancelled/forfeited	$ 17.29
Weighted - average option exercise price, Ending balance	$ 11.01
Number of restricted stock and board shares issued
Number of restricted stock and board shares issued, Beginning balance	133,639
Number of restricted stock and board shares issued, Granted	27,925
Number of restricted stock and board shares issued, Exercised	0
Number of restricted stock and board shares issued, Cancelled/forfeited	(20,911)
Number of restricted stock and board shares issued, Ending balance	140,653
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	0
Number of restricted stock units outstanding, Exercised	0
Number of restricted stock units outstanding, Cancelled/forfeited	(2,907)
Number of restricted stock units outstanding, Ending balance	43,034