Royalty Agreement, Note Payable, and Accrued Interest - Additional Information (Detail)		1 Months Ended	3 Months Ended		12 Months Ended
	May. 23, 2014	Aug. 31, 2006 Patents	Mar. 31, 2014 USD ($)	Jun. 30, 2011 USD ($) $ / shares shares	Dec. 31, 2015	Dec. 31, 2014 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2013 USD ($)
Debt Instrument [Line Items]
U.S. patents along with foreign counterparts | Patents		12
Quarterly royalty payments rate						3.00%
Royalty revenue						$ 200,000
Royalty financing agreement with a syndicate of lenders				$ 8,500,000
Capitalization of fees expenses				$ 473,000
Lender warrants to purchase common stock | shares				71,022
Lender warrants to purchase common stock, before stock split | shares				2,840,909
Class of warrant or right, exercise price of warrants or rights | $ / shares				$ 8.80
Class of warrant or right, exercise price of warrants or rights, before stock split | $ / shares				$ 0.22
Common stock premium rate				20.00%
Number of trading days for the average closing price				10 days
Warrants expiration date				Dec. 31, 2016
Warrants account for as equity instrument, fair value				$ 390,000
Discount interest rate				18.70%
Capitalized expenses amortization period				48 months
Cash payments to lenders for accrued interest							$ 167,000
Cumulative cash shortfall agreement from default stands								$ 525,000
Transferred rights, effective date					Feb. 28, 2014
Gain from fair value of assigned interests			$ 5,823,000			5,823,000
Gain from extinguishment of debt			$ 3,041,000			$ 3,041,000
Common Stock [Member]
Debt Instrument [Line Items]
Reverse stock split ratio					1-for-40
Reverse stock split conversion ratio	0.025