STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($)	Preferred Stock [Member] Series B Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Treasury Stock [Member]	Total
Balance at Dec. 31, 2014	$ 0	$ 9,321	$ 377,022,587	$ (306,507,584)	$ (2,612,861)	$ 67,911,463
Balance (in shares) at Dec. 31, 2014	0	9,320,331
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock options/warrants for compensation and services	$ 0	$ 0	7,384,656	0	0	7,384,656
Issuance of stock options/warrants for compensation and services (in shares)	0	0
Common stock issued in connection with a public offering	$ 0	$ 1,744	26,778,324	0	0	26,780,068
Common stock issued in connection with a public offering (in shares)	0	1,744,167
Options and warrants exercised	$ 0	$ 48	589,953	0	0	590,001
Options and warrants exercised (in shares)	0	48,726
Retirement of treasury stock	$ 0	$ (33)	(2,612,828)	0	2,612,861	0
Retirement of treasury stock (in shares)	0	(33,213)
Net loss	$ 0	$ 0	0	(58,587,190)	0	(58,587,190)
Balance at Dec. 31, 2015	$ 0	$ 11,080	409,162,692	(365,094,774)	0	44,078,998
Balance (in shares) at Dec. 31, 2015	0	11,080,011
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock options/warrants for compensation and services	$ 0	$ 0	6,735,576	0	0	6,735,576
Issuance of stock options/warrants for compensation and services (in shares)	0	0
Common stock issued in connection with a public offering	$ 550,000	$ 6,685	25,220,572	0	0	25,777,257
Common stock issued in connection with a public offering (in shares)	550	6,685,362
Options and warrants exercised	$ 0	$ 64	744,087	0	0	744,151
Options and warrants exercised (in shares)	0	64,393
Warrants issued in connection with a public offering	$ 0	$ 0	(6,923,551)	0	0	(6,923,551)
Preferred stock conversion	$ (32,000)	$ 76	31,924	0	0	0
Preferred stock conversion (in shares)	(32)	76,191
Issuance of restricted stock grant	$ 0	$ 388	1,937	0	0	2,325
Issuance of restricted stock grant (in shares)	0	387,597
Warrants issued in connection with term loan	$ 0	$ 0	633,749	0	0	633,749
Beneficial conversion feature - Series B preferred stock	(314,286)	0	314,286	0	0	0
Series B preferred stock deemed dividend	314,286	0	(314,286)	0	0	0
Class action settlement share issuance	$ 0	$ 260	4,499,740	0	0	4,500,000
Class action settlement share issuance (in shares)	0	260,263
Net loss	$ 0	$ 0	0	(50,771,221)	0	(50,771,221)
Balance at Dec. 31, 2016	$ 518,000	$ 18,553	440,106,726	(415,865,995)	0	$ 24,777,284
Balance (in shares) at Dec. 31, 2016	518	18,553,817				18,553,817
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of stock options/warrants for compensation and services	$ 0	$ 0	3,344,520	0	0	$ 3,344,520
Issuance of stock options/warrants for compensation and services (in shares)	0	0
Common stock issued in connection with a public offering	$ 0	$ 5,000	13,946,218	0	0	13,951,218
Common stock issued in connection with a public offering (in shares)	0	5,000,000
Options and warrants exercised	$ 0	$ 881	3,012,779	0	0	$ 3,013,660
Options and warrants exercised (in shares)	0	880,788				900,000
Preferred stock conversion	$ (518,000)	$ 1,233	516,767	0	0	$ 0
Preferred stock conversion (in shares)	(518)	1,233,334
Issuance of restricted stock grant	$ 0	$ 388	0	0	0	388
Issuance of restricted stock grant (in shares)	0	387,597
Warrants repriced to term loan lender	$ 0	$ 0	76,549	0	0	76,549
Shares issued in connection with licensing sale	$ 0	$ 1,970	6,073,677	0	0	6,075,647
Shares issued in connection with licensing sale (in shares)	0	1,969,697
1 - 6 reverse stock split fractional shares	$ 0	$ 12	(12)	0	0	$ 0
1 - 6 reverse stock split fractional shares (in shares)	0	12,268				12,268
Warrant liability exercises	$ 0	$ 0	1,894,589	0	0	$ 1,894,589
Banking fee on warrant exercises	0	0	(2,368)	0	0	(2,368)
Net loss	0	0	0	(34,986,432)	0	(34,986,432)
Balance at Dec. 31, 2017	$ 0	$ 28,037	$ 468,969,445	$ (450,852,427)	$ 0	$ 18,145,055
Balance (in shares) at Dec. 31, 2017	0	28,037,501				28,037,501