Supplemental Cash Flow Information - Summary of Additional Cash Flow Information (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Supplemental disclosures of cash flow information:
Cash paid for interest		$ 1,161
Cash paid for dividends		157
Non-cash investing and financing activities:
Accrued preferred stock dividend		391
Accrued warrant liability		11,078
Accrued derivative liability		815
Subscription receivable		550
Conversion of preferred stock derivative balance into common stock		79
Cashless exercise of warrants recorded as a liability	(298)
Common stock issued in connection with conversion of debt		$ 229