Stock-Based Compensation - Summary of Outstanding Stock Options and Related Activity (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Outstanding shares, beginning balance	2,275	2,167	2,706
Granted shares	120	826	25
Exercised shares		(32)	(7)
Cancelled shares	(225)	(686)	(557)
Outstanding shares, ending balance	2,170	2,275	2,167
Outstanding weighted average exercise price, beginning balance	$ 7.02	$ 11.03	$ 11.69
Exercisable, shares	1,573	1,474	2,167	2,545
Granted, weighted average exercise price	$ 1.31	$ 1.39	$ 4.07
Vested and expected to vest, shares	2,092
Exercised, weighted average exercise price		$ 0.50	$ 1.77
Cancelled, weighted average exercise price	$ 6.52	$ 12.37	$ 14.04
Outstanding weighted average exercise price, Ending balance	$ 6.76	$ 7.02	$ 11.03
Exercisable, weighted average exercise price	$ 8.81	$ 10.09	$ 11.03	$ 11.54
Vested and expected to vest, weighted average exercise price	$ 6.96
Aggregate intrinsic value
Exercisable, Aggregate intrinsic value
Vested and expected to vest, Aggregate Intrinsic Value