Fair Value Measurements - Additional Information (Detail) (USD $)	6 Months Ended
	Jun. 30, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assumed stock prices	75.00%
Change in stock price	$ 0.030
Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Probability of existing note holders	50.00%
Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Probability of existing note holders	90.00%