2013 Annual Meeting of Stockholders - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Stockholder Equity [Line Items]
Shares of common stock authorized before the amendment	140,000,000
Common stock shares authorized	280,000,000	140,000,000
Percentage of holding by affiliates upon which warrants may not be exercised	19.99%
Minimum [Member]
Stockholder Equity [Line Items]
Percentage of holding by affiliates upon which warrants may not be exercised	19.99%
Series D and E Preferred Stock [Member]
Stockholder Equity [Line Items]
Voting power limit prior to shareholder approval	19.99%
Series D and Series E Voting Power Limit	19.99%
Series D Preferred Stock [Member]
Stockholder Equity [Line Items]
Beneficial Ownership of Series D and affiliates at which dividends may not be paid in voting shares	19.99%
Beneficial Ownership % (in the event that it was approved by stockholders) of Series D and affiliates at which dividends may not be paid in voting shares	35.00%
Percentage of holding by affiliates upon which holder might not convert shares	19.99%
Percentage of holding by affiliates in the event that it was approved by stockholders upon which holder might not convert preferred shares into common shares	35.00%