Fair Value Measurements - Additional Information (Detail) (USD $)			12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Accrued Warrant Liability [Member]	Dec. 31, 2013 Compensatory Stock Options not Yet Issued [Member]
Assets or liabilities	$ 0	$ 0
Increase in expected term			10.00%
Increase in accrued warrant liability with increase in expected term			22.00%
Decrease in expected term			10.00%
Decrease in accrued warrant liability with decrease in expected term			16.00%
Increase in stock price			10.00%
Increase in accrued warrant liability with increase in stock price			32.00%
Decrease in stock price			10.00%
Decrease in accrued warrant liability with decrease in stock price			26.00%
Increase or decrease in expected term				10.00%
Increase or decrease in amount accrued with expected term change				6.00%
Increase or decrease in stock price				10.00%
Increase or decrease in amount accrued with stock price change				10.00%