Stock-Based Compensation - Additional Information (Detail) (USD $)	1 Months Ended	12 Months Ended		150 Months Ended								12 Months Ended					2 Months Ended	12 Months Ended				1 Months Ended	12 Months Ended	1 Months Ended	12 Months Ended			12 Months Ended			1 Months Ended	12 Months Ended								1 Months Ended		12 Months Ended					1 Months Ended	12 Months Ended	1 Months Ended		12 Months Ended	1 Months Ended				12 Months Ended		1 Months Ended	12 Months Ended		1 Months Ended									12 Months Ended	1 Months Ended	12 Months Ended						12 Months Ended	1 Months Ended		12 Months Ended				1 Months Ended		1 Months Ended						12 Months Ended
	Feb. 28, 2009	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012	Dec. 31, 2010	Feb. 25, 2008	Feb. 04, 2008	Jan. 31, 2003	Dec. 31, 2002	Dec. 31, 2001	Aug. 31, 2001	Dec. 31, 2011 Scenario 1	Dec. 31, 2011 Scenario 2	Dec. 31, 2012 Cashless	Dec. 31, 2011 Cashless	Dec. 31, 2011 Monte Carlo Option Pricing Model	Feb. 29, 2004 Stock Option	Dec. 31, 2012 Stock Option	Dec. 31, 2011 Stock Option	Dec. 31, 2003 Stock Option	Dec. 31, 2011 Restricted Stock	Mar. 31, 2002 Non Employee Board Member and Former Member of Audit Committee Second Consulting Agreement	Dec. 31, 2002 Non Employee Board Member and Former Member of Audit Committee Second Consulting Agreement	Jun. 30, 2003 Non Employee Board Member and Former Member of Audit Committee Third Consulting Agreement	Dec. 31, 2004 Non Employee Board Member and Former Member of Audit Committee Third Consulting Agreement	Dec. 31, 2003 Non Employee Board Member and Former Member of Audit Committee Third Consulting Agreement	Dec. 31, 2002 Non Employee Board Member and Former Member of Audit Committee Stock Option	Dec. 31, 2002 Non Employee Board Member and Former Member of Audit Committee Stock Option Second Consulting Agreement	Dec. 31, 2004 Non Employee Board Member and Former Member of Audit Committee Stock Options Third Consulting Agreement	Dec. 31, 2003 Non Employee Board Member and Former Member of Audit Committee Stock Options Third Consulting Agreement	Jan. 31, 2003 Board of Directors	Dec. 31, 2011 Board of Directors	Dec. 31, 2010 Board of Directors	Dec. 31, 2009 Board of Directors	Dec. 31, 2004 Board of Directors	Dec. 31, 2003 Board of Directors	Dec. 31, 2004 Board of Directors Stock Option	Dec. 31, 2003 Board of Directors Stock Option	Dec. 31, 2011 Board of Directors Restricted Stock	Nov. 30, 2005 Member of Scientific Advisory Board	May 31, 2003 Member of Scientific Advisory Board	Dec. 31, 2004 Member of Scientific Advisory Board	Dec. 31, 2003 Member of Scientific Advisory Board	Dec. 31, 2005 Member of Scientific Advisory Board Stock Option	Dec. 31, 2004 Member of Scientific Advisory Board Stock Option	Dec. 31, 2003 Member of Scientific Advisory Board Stock Option	Sep. 30, 2003 Board Member and Member of Scientific Advisory Board	Dec. 31, 2003 Board Member and Member of Scientific Advisory Board Stock Option	Oct. 31, 2003 Former Chief Financial Officer	Sep. 30, 2003 Former Chief Financial Officer	Dec. 31, 2003 Former Chief Financial Officer	Oct. 31, 2003 Former Chief Financial Officer Cashless	Oct. 31, 2003 Former Chief Financial Officer Stock Option	Apr. 30, 2004 Investor Relations Firm	Mar. 31, 2004 Investor Relations Firm	Dec. 31, 2005 Investor Relations Firm	Dec. 31, 2004 Investor Relations Firm	Mar. 31, 2004 Investor Relations Firm Stock Option	Dec. 31, 2003 Investor Relations Firm Stock Option Options Vested on December Thirty One Twenty Zero Three	Dec. 31, 2004 Investor Relations Firm Stock Option Options Vested on January and February Twenty Zero Four	Aug. 31, 2012 Consultant	May 31, 2012 Consultant	Nov. 15, 2011 Consultant	Mar. 31, 2009 Consultant	Feb. 28, 2009 Consultant	Apr. 30, 2008 Consultant	Mar. 31, 2008 Consultant	Dec. 31, 2007 Consultant	Mar. 31, 2006 Consultant	Dec. 31, 2011 Consultant	Mar. 31, 2006 Consultant Stock Option	Dec. 31, 2009 Consultant Stock Option	Dec. 31, 2008 Consultant Stock Option	Dec. 31, 2007 Consultant Stock Option	Dec. 31, 2011 Consultant Restricted Stock Scenario 2	Dec. 31, 2012 Minimum	Dec. 31, 2011 Minimum	Dec. 31, 2012 Maximum	Apr. 30, 2004 Maximum Investor Relations Firm	Mar. 31, 2004 Maximum Investor Relations Firm	Dec. 31, 2001 Consulting Agreement Non Employee Board Member and Former Member of Audit Committee	Dec. 31, 2003 Consulting Agreement Non Employee Board Member and Former Member of Audit Committee Stock Option	Dec. 31, 2002 Consulting Agreement Non Employee Board Member and Former Member of Audit Committee Stock Option	Dec. 31, 2001 Consulting Agreement Non Employee Board Member and Former Member of Audit Committee Stock Option	Oct. 31, 2001 Stock Incentive Plan Twenty Zero One	Dec. 31, 2012 Stock Incentive Plan Twenty Zero One	Oct. 31, 2001 Stock Incentive Plan Twenty Zero One Minimum	Oct. 31, 2001 Stock Incentive Plan Twenty Zero One Maximum	Dec. 31, 2012 Non Employee Director Stock Options Plan, Twenty Zero Three	Dec. 31, 2003 Non Employee Director Stock Options Plan, Twenty Zero Three	Dec. 31, 2012 Incentive Compensation Plan 2009	Feb. 28, 2009 Incentive Compensation Plan 2009	Dec. 31, 2012 Non Qualified Options Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of share based compensation plans		3		3
Number of common stock for issuance upon exercise of grants																																																																																					833,334					166,667		3,333,334
Stock awards, vesting period																																																																																					3 years
Stock options expiration period																																																																																							3 years	10 years
Stock awards, available for future grant																																																																																						291,992			146,557		979,259
Non-plan stock option grants to employees and non-employees																																																																																													1,477,379
Non-plan grants outstanding		3,539,961	3,091,474	3,539,961	1,965,748																																																																																								1,440,045
Expected life		5 years 9 months 22 days	5 years 1 month 17 days	5 years 2 months 9 days												10 years																																																												5 years		10 years
Expected dividend yield used in the option valuation model		0.00%	0.00%	0.00%
Stock Option expected to vest only upon achievement of certain market conditions			166,668									83,334	83,334
Total fair value of options vested		$ 2,447,000	$ 2,153,000	$ 13,056,000								$ 5,000,000,000	$ 10,000,000,000
Unrecognized compensation cost		5,628,000		5,628,000												1,006,000
Unrecognized compensation cost, recognition period		3 years 8 months 12 days														5 years 6 months
Annualized volatility		116.00%	131.00%	119.00%												110.00%
Annualized risk free rate		0.90%	1.90%	1.84%												3.50%
Common stock price		$ 2.05		$ 2.05		$ 2.40	$ 3.54	$ 6.00	$ 21.00	$ 13.68	$ 13.68																																																																		$ 9.00
Weighted-average grant-date fair values of options granted		$ 1.77	$ 6.07
Unvested option		1,472,051	1,317,480	1,472,051
Number of stock options exercised		51,830	216,443											90,253	83,334																																					8,334
Stock options exercised		96,000	253,000
Proceeds from exercise of stock options		0	234,000
Number of shares issued in the conversion of options in a noncash transaction		51,830	64,273																																														2,772
Intrinsic value of options exercised		162,000	1,174,000	1,724,000
Number of options vested	83,334	595,420	380,391														10,000			2,500			3,334																																	2,500	7,500							833			833		834
Number of options granted																						4,000		4,000							16,667										1,667						4,167			16,667																															33,334
Exercise price of stock options		$ 2.13	$ 7.02																			$ 21.00									$ 21.00									$ 15.66	$ 21.00						$ 24.30		$ 17.82	$ 24.30				$ 30.96	$ 34.80										$ 0	$ 2.64		$ 3.78	$ 22.50												$ 21.00
Stock option, fair market value																																																																																	239,000
Common stock price per share																						$ 12.96		$ 21.00							$ 16.80									$ 8.10	$ 16.80						$ 14.64						$ 26.70												$ 0.72	$ 2.34		$ 2.76	$ 13.20												$ 13.68
Stock-based compensation expense		2,792,000	3,245,000	12,374,000																								41,000	17,000	40,000							51,000	193,000	18,000					7,000	5,000	13,000		122,000	40,000		74,000					14,000	67,000		29,000	23,000											33,000	24,000	15,000	2,000	110,000							71,000	64,000	147,000
Number of options granted per month																						334
Number of options vest per month																						334		334																															834
Stock option, fair market value																						11,000		33,000							156,000										16,000
Deferred compensation																											11,000
Fair value adjustments of unvested options																									(2,000)	21,000									4,000	82,000						2,000	6,000
Options vesting rate, vested immediately																															33.33%										50.00%
Stock option issued																																								834																10,000		4,167							33,334	8,000		834	2,500
Number of options issuable as services are performed																																																																															10,000	16,667
Number of options vest per month																																																						834
Extension of exercise period																		90 days	90 days
Additional stock-based compensation expense		271,000	63,000
Common stock options granted, shares																																																													4,348	7,000
Fair market value of shares																																																													10,000	16,000
Restricted common stock granted		1,379,739																																416,670
Restricted common stock vested																					46,876											390,628	26,042
Restricted shares, value																																		$ 450,000																													$ 113,000
Restricted shares, value per share																																		$ 1.08																													$ 5.40
Restricted common stock issued																					20,834																																																	20,834