B. SUMMARY OF CRITICAL ACCOUNTING POLICIES (Tables)

12 Months Ended

Dec. 31, 2018

Accounting Policies [Abstract]

Property and equipment estimated useful life

Laboratory equipment	3 – 5 years
Office equipment	5 years
Office furniture and fixtures	7 years
Computer equipment and software	3 years
Leasehold improvements	Shorter of useful life or remaining lease term

Anti-dilutive securities

	Year ended December 31,
	2018		2017
Warrants to purchase common stock		10,690,718		120,773
Convertible preferred shares outstanding		2,854,593		-
Options to purchase common stock		241,735		188,744
Restricted stock grants		19,914		-

Fair values of investments by type

	December 31, 2018
	Amortized Cost		Accrued Interest		Gross Unrealized Gains		Gross Unrealized losses			Estimated Fair Value
Obligations of U.S. Government and its agencies	$	118,719	$	379	$	333	$	-		$	119,431
Corporate debt securities		373,201		1,818		293		(110	)		375,202
Total investments	$	491,920	$	2,197	$	626	$	(110	)	$	494,633

Scheduled of investments maturity

	December 31, 2018		December 31, 2017
Maturing in one year or less	$	494,633	$	6,122,400
Maturing after one year through three years		-		1,809,428
Total investments	$	494,633	$	7,931,828

Significant unobservable inputs

Series C Warrants	December 31, 2017
Closing stock price	$	9.80
Expected dividend rate		0	%
Expected stock price volatility		81.26	%
Risk-free interest rate		1.83	%
Expected life (years)		1.56

Impact of new accounting standard

	Preferred stock		Common stock		Additional paid in capital		Accumulated other comprensive loss / gain			Accumulated deficit			Totoal stockholder's deficit
Balance - December 31, 2017	$	-	$	141	$	222,397,198	$	(16,193	)	$	(213,499,285	)	$	8,881,861
Balance - December 31, 2018 before effect of ASU 2017-11		285		379		239,380,012		516			(227,643,334	)		11,737,858
Effect of ASU 2017-11		-		-		192,082		-			(158,409	)		33,673
Balance - December 31, 2018	$	285	$	379	$	239,572,094	$	516		$	(227,801,743	)	$	11,771,531

Fair value measurements

			Fair Value Measurements at Reporting Date Using
	Balance as of December 31, 2018		Quoted prices in Active Markets for Identical Securities (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Current Assets
Cash and cash equivalents	$	12,367,321	$	12,367,321	$	-	$	-
Marketable securities	$	494,633	$	-	$	494,633	$	-

			Fair Value Measurements at Reporting Date Using
	Balance as of December 31, 2017		Quoted prices in Active Markets for Identical Securities (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Current Assets
Cash and cash equivalents	$	1,604,810	$	1,604,810	$	-	$	-
Marketable securities	$	6,122,400	$	-	$	6,122,400	$	-
Long-term Assets
Marketable securities	$	1,809,428	$	-	$	1,809,428	$	-
Current Liabilities
Warrant liabilities	$	33,673	$	-	$	-	$	33,673