Stockholders' Equity-Common and Preferred Shares - Summary of the Company's Stock Option Activity under ts 2005 Plan (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Shares, Options outstanding, Beginning balance	143
Shares, Granted	77
Shares, Forfeited and expired	(42)
Shares, Options outstanding, Ending balance	178	143
Options exercisable at June 30, 2013, Shares	73
Options vested or expected to vest at June 30, 2013, Shares	134
Weighted Average Exercise Price, Options outstanding Beginning balance	$ 19.73
Weighted Average Exercise Price, Granted	$ 4.38
Weighted Average Exercise Price, Forfeited and expired	$ 17.66
Weighted Average Exercise Price, Options outstanding, Ending balance	$ 13.66	$ 19.73
Options exercisable at June 30, 2013, Weighted Average Exercise Price	$ 21.98
Options vested or expected to vest at June 30, 2013, Weighted Average Exercise Price	$ 15.60
Weighted Average Remaining Contractual Life, Options outstanding at December 31, 2012	8 years 3 months	8 years 7 months 21 days
Weighted Average Remaining Contractual Life, Options outstanding at June 30, 2013	8 years 3 months	8 years 7 months 21 days
Options exercisable at June 30, 2013, Weighted Average Remaining Contractual Life	6 years 8 months 27 days
Options vested or expected to vest at June 30, 2013, Weighted Average Remaining Contractual Life	7 years 10 months 28 days
Aggregate Intrinsic Value, Options outstanding Beginning balance
Aggregate Intrinsic Value, Options outstanding Ending balance
Options exercisable at June 30, 2013, Aggregate Intrinsic Value
Options vested or expected to vest at June 30, 2013, Aggregate Intrinsic Value