|
Warrants to Purchase Common Stock - Additional Information (Detail) (USD $)
|
1 Months Ended | 12 Months Ended | 90 Months Ended | 1 Months Ended | 12 Months Ended | 1 Months Ended | 12 Months Ended | 12 Months Ended | 12 Months Ended | 1 Months Ended | 0 Months Ended | 12 Months Ended | 12 Months Ended | |||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Aug. 31, 2012
|
Jun. 30, 2012
|
Dec. 31, 2013
|
Dec. 31, 2012
|
Dec. 31, 2011
|
Dec. 31, 2013
|
Aug. 16, 2012
|
Dec. 31, 2012
Non Employee Warrants [Member]
|
Aug. 31, 2012
Non Employee Warrants [Member]
|
Apr. 30, 2012
Non Employee Warrants [Member]
|
Dec. 31, 2011
Non Employee Warrants [Member]
|
Sep. 30, 2011
Non Employee Warrants [Member]
|
Mar. 31, 2011
Non Employee Warrants [Member]
|
Feb. 28, 2011
Non Employee Warrants [Member]
|
Nov. 30, 2010
Non Employee Warrants [Member]
|
Dec. 31, 2013
Non Employee Warrants [Member]
|
Dec. 18, 2012
Non Employee Warrants [Member]
|
Aug. 28, 2012
Non Employee Warrants [Member]
|
Aug. 16, 2012
Non Employee Warrants [Member]
|
Apr. 02, 2012
Non Employee Warrants [Member]
|
Nov. 22, 2010
Non Employee Warrants [Member]
|
Sep. 30, 2011
Non Employee Warrants [Member]
Maximum [Member]
|
Sep. 30, 2011
Non Employee Warrants [Member]
Minimum [Member]
|
Apr. 30, 2012
Warrants to Purchase Series C Shares [Member]
|
Dec. 31, 2013
Warrants to Purchase Series C Shares [Member]
|
Dec. 31, 2013
National Securities Corporation [Member]
|
Dec. 31, 2013
National Securities Corporation [Member]
Warrants to Purchase Series C Shares [Member]
|
Dec. 31, 2013
Debt Placement Agent Warrants [Member]
|
Apr. 26, 2010
Debt Placement Agent Warrants [Member]
|
Apr. 26, 2010
Debt Placement Agent Warrants [Member]
Series A [Member]
|
Apr. 26, 2010
Debt Placement Agent Warrants [Member]
Senior Convertible Notes 2008 [Member]
Series A [Member]
|
Apr. 26, 2010
Debt Placement Agent Warrants [Member]
Senior Convertible Notes 2009 [Member]
Series A [Member]
|
Dec. 31, 2007
Common Stock [Member]
|
Apr. 30, 2012
Common Stock [Member]
Warrants to Purchase Series C Shares [Member]
|
Nov. 15, 2011
Common Stock [Member]
Warrants to Purchase Series C Shares [Member]
|
Dec. 31, 2013
Common Stock [Member]
Warrants to Purchase Series C Shares [Member]
|
Apr. 02, 2012
Common Stock [Member]
Warrants to Purchase Series C Shares [Member]
|
Dec. 31, 2013
Preferred Stock Placement Warrants [Member]
|
Dec. 31, 2013
Preferred Stock Placement Warrants [Member]
Series A [Member]
|
Dec. 31, 2013
Preferred Stock Placement Warrants [Member]
Series A [Member]
Maximum [Member]
|
Dec. 31, 2013
Preferred Stock Placement Warrants [Member]
Series A [Member]
Minimum [Member]
|
Dec. 31, 2009
PCP Warrants [Member]
|
Dec. 31, 2011
PCP Warrants [Member]
Series A [Member]
|
Dec. 31, 2009
PCP Warrants [Member]
Series A [Member]
|
|
| Warrants To Purchase Common Stock [Line Items] | ||||||||||||||||||||||||||||||||||||||||||||
| Period of Issued Warrants | 5 years | 7 years | ||||||||||||||||||||||||||||||||||||||||||
| Notes Principal Amount Percentage | 10.00% | 10.00% | 40.00% | 40.00% | ||||||||||||||||||||||||||||||||||||||||
| Warrant exercise price | 5.72 | 6.00 | 2.95 | 1.37 | 1.37 | 4.88 | 5.65 | 5.72 | 1.37 | 9.23 | 5.59 | 1.00 | 9.23 | 9.23 | 8.39 | 1.00 | 6.15 | 9.23 | ||||||||||||||||||||||||||
| Exercise price percentage | 110.00% | 110.00% | ||||||||||||||||||||||||||||||||||||||||||
| Issued warrants to purchase common stock | 20,000 | 5,000 | 75,000 | 60,000 | 50,000 | 35,000 | 73,009 | 25,000 | 25,000 | 41,716 | 461,263 | 48,510 | 41,716 | 258,421 | 40,787 | 27,175 | ||||||||||||||||||||||||||||
| Fair value of the warrant | $ 92,000 | $ 19,100 | $ 144,000 | $ 98,000 | $ 69,000 | $ 103,000 | $ 113,000 | $ 38,000 | $ 200,000 | $ 100,000 | $ 100,000 | $ 600,000 | $ 47,000 | |||||||||||||||||||||||||||||||
| Volatility | 104.51% | 97.45% | 110.30% | 91.10% | 95.40% | 93.20% | 93.70% | 96.30% | 90.80% | 92.40% | 94.40% | 92.00% | ||||||||||||||||||||||||||||||||
| Risk free rate | 1.06% | 0.28% | 0.83% | 0.40% | 3.58% | 2.65% | 1.40% | 0.90% | 0.40% | 0.93% | 3.30% | 2.00% | ||||||||||||||||||||||||||||||||
| Estimated per share fair value | $ 1.96 | $ 8.00 | $ 3.45 | |||||||||||||||||||||||||||||||||||||||||
| Dividend yield | 0.00% | 0.00% | 0.00% | 0.00% | 0.00% | 0.00% | 0.00% | |||||||||||||||||||||||||||||||||||||
| Fair Value Assumptions, Expected Term | 6 years | 3 years | 5 years | 10 years | 5 years | 5 years | ||||||||||||||||||||||||||||||||||||||
| Warrants issued | 20,970 | |||||||||||||||||||||||||||||||||||||||||||
| Warrant Fair Value | $ 8.50 | |||||||||||||||||||||||||||||||||||||||||||
| Stock Issued During Period Shares warrants Exercised | 78,710 | 78,636 | ||||||||||||||||||||||||||||||||||||||||||
| Cashless Exercise Of Warrants | 153,415 | 328,510 | ||||||||||||||||||||||||||||||||||||||||||
| Investment Warrants, Exercise Price | $ 5.00 | $ 5.59 | $ 5.45 | |||||||||||||||||||||||||||||||||||||||||
| Stock Issued During Period Shares New Issues | 5,750,000 | 10,558,422 | 3,361 | 340 | 2,125,096 | |||||||||||||||||||||||||||||||||||||||
| Proceeds From Issuance Of Common Stock | 26,400,000 | 92,399,000 | 28,855,000 | 193,000 | 121,452,000 | 1,000 | ||||||||||||||||||||||||||||||||||||||
| Class of Warrant or Right, Outstanding | 711,895 | |||||||||||||||||||||||||||||||||||||||||||
| Fee paid to National Securities Corporation as consideration for its services as the placement agent | 10.00% | |||||||||||||||||||||||||||||||||||||||||||
| Fair value of warrants reduction in carrying amount in share | 1,300,000 | |||||||||||||||||||||||||||||||||||||||||||
| Amount Charge Due To Mark To Market Valuation Of Warrants Exercisable For Common Stock | 1,400,000 | |||||||||||||||||||||||||||||||||||||||||||
| Final fair value of common stock | $ 2,700,000 | |||||||||||||||||||||||||||||||||||||||||||
| Common Stock Shares Issued | 39,652,950 | 24,400,754 | 39,652,950 | 534 | ||||||||||||||||||||||||||||||||||||||||
| Common Stock Shares Exercised | 2,986 | |||||||||||||||||||||||||||||||||||||||||||
| Fair market value of common stock on the date of exercise | $ 6.81 | |||||||||||||||||||||||||||||||||||||||||||