Subsequent Events - Additional Information (Detail) $ / shares in Units, $ in Thousands				1 Months Ended										12 Months Ended
	Jan. 05, 2017	Dec. 14, 2016	Apr. 15, 2015	Feb. 28, 2017 USD ($) $ / shares shares	Jan. 31, 2017 USD ($) $ / shares shares	Sep. 30, 2016 USD ($) shares	Jun. 30, 2016 USD ($)	Apr. 30, 2016 USD ($) shares	Dec. 31, 2015 USD ($) shares	May 31, 2015 USD ($) shares	Feb. 28, 2015 USD ($) shares	Aug. 31, 2014 USD ($)	Jul. 31, 2012 USD ($)	Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 USD ($)	Feb. 23, 2017 USD ($)	Nov. 30, 2015 shares
Subsequent Event [Line Items]
Debt instrument, periodic payment, principal														$ 9,800
Outstanding principal amount									$ 14,341					8,221	$ 14,341
Common stock units issued | shares										215,000	110,833
Proceeds from issuance of common stock and common stock warrants						$ 15,600	$ 9,500	$ 3,500	$ 9,970	$ 17,200	$ 6,700	$ 18,000	$ 57,400	$ 28,661	$ 33,820	$ 18,000
Common stock shares issued | shares									1,080,352					7,074,246	1,080,352
Reverse split of common stock		one-for-twenty	one-for-fifteen
Reverse stock split ratio		0.05	0.067
NASDAQ listing minimum bid price requirement description														In January 2017, the Company received notice from The NASDAQ Stock Market LLC that effective January 20, 2017 it had regained compliance with the NASDAQ Capital Market’s minimum bid price continued listing requirement of at least ten consecutive days with a closing bid price of its common stock in excess of $1.00.
Series G
Subsequent Event [Line Items]
Number of securities called by each warrant | shares								1
Warrants, expiration date														Apr. 01, 2017
Series H
Subsequent Event [Line Items]
Number of securities called by each warrant | shares								1
Warrants, expiration date														Oct. 01, 2016
Subsequent Event
Subsequent Event [Line Items]
Proceeds from issuance of common stock and common stock warrants				$ 11,900
Reverse split of common stock	one-for-twenty
Reverse stock split ratio	0.05
Regain compliance with listing qualifications initial period date					Jan. 20, 2017
Regain compliance with listing qualifications minimum number of consecutive business period					10 days
Regain compliance with listing qualifications common stock minimum bid price | $ / shares					$ 1.00
Subsequent Event | Series K Warrant
Subsequent Event [Line Items]
Warrant , exercise price | $ / shares				$ 2.35
Warrants, expiration date				Feb. 17, 2022
Subsequent Event | Series M Warrant
Subsequent Event [Line Items]
Warrant , exercise price | $ / shares				$ 2.35
Warrants, expiration date				Nov. 17, 2017
Subsequent Event | Series L Warrant
Subsequent Event [Line Items]
Warrant , exercise price | $ / shares				$ 0.01
Warrants, expiration date				Feb. 17, 2018
Warrant, exercise price aggregate | $ / shares				$ 1.90
Subsequent Event | Series G
Subsequent Event [Line Items]
Common stock units issued | shares				5,680,000
Number of securities called by each warrant | shares				1
Public offering price per share | $ / shares				$ 1.90
Subsequent Event | Series G | Series K Warrant
Subsequent Event [Line Items]
Number of securities called by each warrant | shares				1
Subsequent Event | Series G | Series M Warrant
Subsequent Event [Line Items]
Number of securities called by each warrant | shares				1
Subsequent Event | Series H
Subsequent Event [Line Items]
Common stock units issued | shares				570,000
Public offering price per share | $ / shares				$ 1.89
Subsequent Event | Series H | Series K Warrant
Subsequent Event [Line Items]
Number of securities called by each warrant | shares				1
Subsequent Event | Series H | Series M Warrant
Subsequent Event [Line Items]
Number of securities called by each warrant | shares				1
Subsequent Event | Series H | Series L Warrant
Subsequent Event [Line Items]
Number of securities called by each warrant | shares				1
Convertible 2017 Notes
Subsequent Event [Line Items]
Debt instrument maturity date														Mar. 15, 2017	Mar. 15, 2017
Aggregate principal amount on sale of convertible notes									$ 26,108					$ 26,108	$ 26,108
2022 Notes
Subsequent Event [Line Items]
Debt instrument maturity date														Jul. 01, 2022
Percentage of convertible senior notes													7.50%
10% convertible senior notes, maturity date													2022
Outstanding principal amount									$ 14,341					$ 8,221	$ 14,341
Aggregate principal amount on sale of convertible notes													$ 45,000
Common stock shares issued | shares						699,968					8,502			251,832				55,392
2022 Notes | Subsequent Event
Subsequent Event [Line Items]
Percentage of convertible senior notes					7.50%
Aggregate principal amount on sale of convertible notes					$ 8,400
Common stock shares issued | shares					2,155,382
2022 Notes | Subsequent Event | Principal Amount of Convertible Notes
Subsequent Event [Line Items]
Outstanding principal amount					$ 1,200
Whitebox | Convertible 2017 Notes
Subsequent Event [Line Items]
Debt instrument maturity date														Mar. 15, 2017
Debt instrument coupon rate														2.00%
Whitebox | Convertible 2017 Notes | Subsequent Event
Subsequent Event [Line Items]
Debt instrument maturity date				Jun. 23, 2017
Percentage of convertible senior notes				10.00%
10% convertible senior notes, maturity date				2017
Debt instrument coupon rate				12.00%
Repayments of debt				$ 8,000
Percentage of net proceeds from underwritten public offering for repayment of debt																	15.00%
Aggregate total principal payment																	$ 9,600
Outstanding principal amount																	$ 16,500
Whitebox | Convertible 2017 Notes | First Installment | Subsequent Event
Subsequent Event [Line Items]
Debt instrument, periodic payment, principal				2,000
Whitebox | Convertible 2017 Notes | April 13, 2017 | Subsequent Event
Subsequent Event [Line Items]
Debt instrument, periodic payment, principal				2,000
Whitebox | Convertible 2017 Notes | May 12, 2017 | Subsequent Event
Subsequent Event [Line Items]
Debt instrument, periodic payment, principal				2,000
Whitebox | Convertible 2017 Notes | June 13, 2017 | Subsequent Event
Subsequent Event [Line Items]
Debt instrument, periodic payment, principal				$ 2,000