Warrants and Derivative Liabilities - Schedule of Fair Value Assumptions Used to Calculate Value of Convertible Note Derivative Feature (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013
Combined principal balances of the term loans		$ 10,411,000	$ 10,411,000	$ 14,389,000	$ 15,380,000
Stock price		$ 1.64	$ 2.34	$ 2.64	$ 2.67
Percentage volume condition met		87.20%	80.20%	87.50%	80.50%
Expected volatility		68.60%	66.30%	65.80%	66.90%
Risk-free interest rate		0.12%	0.10%	0.21%	0.20%
Expected annual dividend yield		16.50%	15.50%	16.70%	16.50%
Recovery rate		35.00%	35.00%	37.00%	30.00%
Redeemable	N/A	yes	yes	yes	yes
Term (years)		9 months	1 year	1 year 3 months 4 days	1 year 6 months 4 days
Dilution effect	N/A	yes	yes	yes	yes
Fair value			$ 200,000	$ 500,000	$ 500,000
Fair value as a percent of par		0.02%	0.70%	3.30%	3.40%