Secured Debt and Convertible Notes - Additional Information (Detail) (USD $)	1 Months Ended	3 Months Ended		12 Months Ended	106 Months Ended			12 Months Ended		1 Months Ended	3 Months Ended		0 Months Ended		1 Months Ended			1 Months Ended
	Jul. 31, 2012	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013 Warrant	Mar. 31, 2014	Dec. 31, 2012	Oct. 31, 2011	Dec. 31, 2013 First Installment	Dec. 31, 2013 Final Installment	Jul. 31, 2012 7.5% convertible senior notes due 2022	Mar. 31, 2014 7.5% convertible senior notes due 2022	Mar. 31, 2014 Convertible Notes Prior To First July Two Thousand Seventeen	May 07, 2014 Subsequent Event	May 09, 2014 Subsequent Event	May 31, 2014 Subsequent Event	Jul. 31, 2012 Loan Agreement 1	Aug. 29, 2010 Loan Agreement 1	Dec. 31, 2013 Loan Agreement	Mar. 31, 2014 Loan Agreement	Aug. 31, 2010 Loan Agreement	Dec. 31, 2013 Restructure Period
Debt Instrument [Line Items]
Borrowings from loan and security agreement																	$ 5,000,000		$ 5,100,000	$ 12,500,000
Proceeds from Convertible Notes																5,400,000
End-of-term payment as percentage of amount borrowed				5.75%												8.00%
Proceeds from the offerings of common stock units					205,340,000													5,100,000
Debt Instrument, Face Amount							15,000,000			45,000,000
Debt Instrument, repurchase amount				15,000,000		5,000,000	10,000,000
Debt Instrument, Interest Rate, Effective Percentage				11.00%
Repayments of outstanding principal															9,300,000
Debt Instrument, Periodic Payment, Principal															1,000,000
Debt Instrument, Payment Terms															36 equal monthly payments commencing in June 2014.
Number of Warrants Outstanding				3
Number of Shares of Common Stock Exercisable for Warrants				388,411
Exercise Price of Common Stock				$ 1.18
Long term borrowing interest rate																					13.00%
Percentage of payment on principal amount and interest due								50.00%	50.00%
Repayments of outstanding principal under additional term loan facilities with TriplePoint													9,300,000
Secured debt, net		10,023,000		10,127,000	10,023,000								1,000,000
Debt payable terms													36 months
Proceeds from issuance of convertible debt, net					42,300,000					40,900,000				25,900,000
Debt Financing agreements additional ability by Other party to invest in Convertible Debt														5,200,000
Debt Financing agreements future additional Term Loan or purchase of additional Convertible Debt														32,000,000
Discount on sale of convertible notes										2,700,000
Debt issuance cost										1,400,000
Percentage of interest on convertible senior notes due										7.50%
Amortization of Debt Discount and Issue Cost		600,000	1,600,000
Interest Expense		500,000	700,000
Long term Debt Interest Rate		40.00%
Amortization period of debt discount		5 years
Amortization period of debt issuance cost		5 years
Convertible notes, conversion date	Jul. 01, 2017	Jul. 01, 2017									Jul. 01, 2017
Loan maturity date		Jul. 01, 2022		Jul. 01, 2022
Conversion Rate		175.6697		175.6697							175.6697	202.0202
Conversion price per share common stock											$ 5.69
Debt instrument, convertible, conversion price											1,000	1,000
Discount rate used in computation of interest payment				2.00%
Valuation rate of shares for conversion				90.00%
Number of trading days for valuation				10 days
Convertible notes converted to common stock		18,100,000			18,100,000
Debt instrument reduced amount				26,900,000
Common stock issuable upon conversion of debt											3,179,608
Common stock issued in connection with settlement liabilities											2,957,775
Common stock issued to settle convertible note related obligation											$ 4,900,000
Percentage repurchase price		100.00%
Number of trading days required for redemption		20 or more trading days
Excess to percentage of conversion price												150.00%
Number of consecutive trading days required for redemption		30 days
Required principal amount in percentage		25.00%