Stock options and warrants (Other Common Stock Purchase Options and Warrants) (Details) (USD $)	9 Months Ended			3 Months Ended		9 Months Ended			1 Months Ended	3 Months Ended		9 Months Ended					3 Months Ended			9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011	Sep. 30, 2012 Other Options and Warrants [Member]	Sep. 30, 2011 Other Options and Warrants [Member]	Sep. 30, 2012 Other Options and Warrants [Member]	Sep. 30, 2011 Other Options and Warrants [Member]	Sep. 30, 2012 Nonvested Options [Member] Other Options and Warrants [Member]	Jun. 30, 2012 Public Offering [Member] perUnitItemType	Sep. 30, 2011 Public Offering [Member]	Sep. 30, 2011 Investor Relations Services [Member]	Sep. 30, 2012 Investor Relations Services [Member]	Sep. 30, 2011 Investor Relations Services [Member]	Sep. 30, 2012 Investor Relations Services [Member] Other Options and Warrants [Member]	Sep. 30, 2011 Investor Relations Services [Member] Excercise Price Range One [Member]	Dec. 31, 2010 Investor Relations Services [Member] Excercise Price Range One [Member]	Sep. 30, 2011 Vice President Marketing and Business [Member]	Sep. 30, 2012 Non-Compensatory Rights [Member] Other Options and Warrants [Member]	Sep. 30, 2012 Rights [Member] Other Options and Warrants [Member]	Sep. 30, 2012 Senior Vice President and Chief Commercial Officer [Member] Other Options and Warrants [Member]	Sep. 30, 2012 Share Based Subsequent Event [Member] Investor Relations Services [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield						0.00%	0.00%
Expected price volatility						141.00%
Expected volatility, minimum							119.00%
Expected volatility, maximum							145.00%
Risk free interest rate						0.74%
Risk-free interest rate, minimum							1.20%
Risk-free interest rate, maximum							1.95%
Expected term, years						5
Expected term (in years), minimum							3
Expected term (in years), maximum							10
Share-based compensation, operating expense				$ 15,403	$ 29,179	$ 58,347	$ 62,446
Shares Underlying Options/Warrants
Other options and warrants, beginning						282,178		7,917										572,505	26,503
Other options and warrants exercised
Other options and warrants granted						325,000		20,000			5,000						6,667			20,000
Other options and warrants vested								(3,470)
Other options and warrants forfeited						(8,170)		(4,447)		22,892	3,751
Other options and warrants, ending				599,008		599,008		20,000										572,505	26,503
Other options and warrants exercisable				274,008		274,008					1,500		1,500		1,251	1,000
Weighted Average Exercise Price
Other options and warrants, beginning						$ 8.7		$ 21.18
Other options and warrants exercised																				$ 3.42
Other options and warrants granted				$ 2.56		$ 2.56		$ 3.42			$ 30.0		$ 30.0				$ 19.5
Other options and warrants vested								$ 23.28
Other options and warrants forfeited				$ 31.69		$ 31.69		$ 19.5		$ 144.6
Other options and warrants, ending				$ 5.06		$ 5.06		$ 3.42
Options and warrants exercisable				$ 36.95		$ 36.95					$ 360.0		$ 360.0		$ 180.3	$ 167.1
Weighted Average Remaining Contractual Term
Other options and warrants outstanding, ending				4.9		4.9
Other options and warrants exercisable						4.7
Aggregate Intrinsic Value
Other options and warrants, ending				82,400		82,400
Other options and warrants execisable
Weighted average grant date fair value
Other options and warrants, beginning								$ 16.14
Other options and warrants granted								$ 3.04
Other options and warrants vested								$ 16.14
Other options and warrants forfeited								$ 16.11
Other options and warrants, ending								$ 3.04
Vesting period											12 months						3 years
Expired														1,503							334
Expired, weighted-average exercise price																					$ 66.0
Expiration of options, years											3									10
Fair value of options, vested and exercisable												20,227	40,454
Unrecognized compensation expense				39,000		39,000
Unrecognized compensation expense, weighted average period of recognition						1
Common stock, shares issued	7,716,480		1,608,146
Net proceeds from issuance of common stock	$ 10,938,512								$ 12,200,000
Warrants, number of shares									305,000
Warrants, exercise price									2.5