Stock-Based Compensation - Summary of Outstanding Stock Options and Related Activity (Detail) - USD ($) $ / shares in Units, shares in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Outstanding shares, beginning balance	2,134	2,170	2,275
Granted shares	75	633	120
Exercised shares	(8)	(4)
Cancelled shares	(556)	(665)	(225)
Outstanding shares, ending balance	1,645	2,134	2,170
Outstanding weighted average exercise price, beginning balance	$ 5.29	$ 6.76	$ 7.02
Exercisable, shares	1,132	1,291	1,573	1,474
Granted, weighted average exercise price	$ 1.27	$ 0.95	$ 1.31
Vested and expected to vest, shares	1,593
Exercised, weighted average exercise price	$ 1.19	1.38
Cancelled, weighted average exercise price	4.05	5.98	6.52
Outstanding weighted average exercise price, Ending balance	5.39	5.29	6.76
Exercisable, weighted average exercise price	7.34	$ 8.04	$ 8.81	$ 10.09
Vested and expected to vest, weighted average exercise price	$ 5.53
Aggregate intrinsic value	$ 0
Exercisable, Aggregate intrinsic value	0
Vested and expected to vest, Aggregate Intrinsic Value	$ 0