Stockholders' Equity-Common and Preferred Shares - Summary of Company's Stock Option Activity Under its 2005 Plan (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Equity [Abstract]
Shares, Options outstanding, Beginning balance	143
Shares, Granted	107
Shares, Forfeited and expired	(45)
Shares, Options outstanding, Ending balance	205	143
Shares, Options exercisable at September 30, 2013	119
Shares, Options vested or expected to vest at September 30, 2013	169
Weighted Average Exercise Price, Options outstanding, Beginning balance	$ 19.73
Weighted Average Exercise Price, Granted	$ 3.90
Weighted Average Exercise Price, Forfeited and expired	$ 16.48
Weighted Average Exercise Price, Options outstanding, Ending balance	$ 12.19	$ 19.73
Weighted Average Exercise Price, Options exercisable at September 30, 2013	$ 15.18
Weighted Average Exercise Price, Options vested or expected to vest at September 30, 2013	$ 13.09
Weighted Average Remaining Contractual Life, Options outstanding	7 years 4 months 17 days	8 years 7 months 21 days
Weighted Average Remaining Contractual Life, Options exercisable at September 30, 2013	6 years 2 months 1 day
Weighted Average Remaining Contractual Life, Options vested or expected to vest at September 30, 2013	7 years 11 days
Aggregate Intrinsic Value, Options outstanding, Beginning balance
Aggregate Intrinsic Value, Options granted
Aggregate Intrinsic Value, Options forfeited and expired
Aggregate Intrinsic Value, Options outstanding, Ending balance
Aggregate Intrinsic Value, Options exercisable at September 30, 2013
Aggregate Intrinsic Value, Options vested or expected to vest at September 30, 2013