Stockholders' Equity - Common and Preferred Shares - Summary of the Company's Stock Option Activity under its 2005 Plan (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share Options outstanding, Beginning Balance	672
Share options, Granted	25
Share options, Forfeited and expired	(8)
Share options outstanding, Ending Balance	689
Share options exercisable, Ending Balance	272
Share options vested or expected to vest, Ending Balance	585
Weighted Average Exercise Price, Options outstanding, Beginning Balance	$ 3.63
Weighted Average Exercise Price, Granted	$ 1.74
Weighted Average Exercise Price, Forfeited and expired	$ 3.28
Weighted Average Exercise Price, Options outstanding, Ending Balance	$ 3.57
Weighted Average Exercise Price, Options exercisable, Ending Balance	$ 4.50
Weighted Average Exercise Price, Options vested or expected to vest, Ending Balance	$ 3.67
Weighted Average Remaining Contractual Life, Options Outstanding, Beginning Balance	8 years 5 months 27 days
Weighted Average Remaining Contractual Life, Options Outstanding, Ending Balance	8 years 3 months 18 days
Weighted Average Remaining Contractual Life, Options exercisable, Ending Balance	7 years 22 days
Weighted Average Remaining Contractual Life, Options vested or expected to vest, Ending Balance	8 years 1 month 24 days
Aggregate Intrinsic Value, Options outstanding, Ending Balance	$ 0
Aggregate Intrinsic Value, Options exercisable outstanding, Ending Balance	0
Aggregate Intrinsic Value, Options vested or expected to vest, Ending Balance	$ 0