Galectin Therapeutics (GALT) 10-K 6 Mar 19 2018 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Feb. 20, 2019	Jun. 30, 2018
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Entity Registrant Name	GALECTIN THERAPEUTICS INC
Entity Central Index Key	1,133,416
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Public Float			$ 213
Trading Symbol	GALT
Entity Common Stock, Shares Outstanding		45,550,226
Entity Shell Company	false
Entity Emerging Growth Company	false
Entity Small Business	true

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 8,253	$ 3,053
Prepaid expenses and other current assets	579	766
Total current assets	8,832	3,819
Property and equipment, net	0	0
Other	174	342
Intangible assets, net	0	0
Total assets	9,006	4,161
Current liabilities:
Accounts payable	297	608
Accrued expenses	1,512	2,292
Accrued dividends payable	299	68
Total current liabilities	2,108	2,968
Total liabilities	2,108	2,968
Commitments and contingencies (Note 10)
Stockholders' (deficit) equity:
Undesignated stock, $0.01 par value; 20,000,000 shares authorized at December 31, 2018 and 2017, 20,000,000 shares designated at December 31, 2018 and 2017, respectively	0	0
Common stock, $0.001 par value; 100,000,000 and 50,000,000 shares authorized at December 31, 2018 and 2017, respectively, 41,190,905 and 35,789,388 issued and outstanding at December 31, 2018 and 2017, respectively	41	36
Additional paid-in capital	194,130	173,363
Retained deficit	(196,215)	(181,168)
Total stockholders' (deficit) equity	5,175	(530)
Total liabilities, redeemable convertible preferred stock and stockholders' (deficit) equity	9,006	4,161
Series C 6% super dividend redeemable convertible preferred stock
Current liabilities:
Convertible preferred stock, value	1,723	1,723
Series A 12% convertible preferred stock
Stockholders' (deficit) equity:
Convertible preferred stock, value	537	557
Series B-1 12% convertible preferred stock
Stockholders' (deficit) equity:
Convertible preferred stock, value	1,761	1,761
Series B-2 12% convertible preferred stock
Stockholders' (deficit) equity:
Convertible preferred stock, value	3,697	3,697
Series B-3 8% convertible preferred stock
Stockholders' (deficit) equity:
Convertible preferred stock, value	$ 1,224	$ 1,224

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Undesignated stock, par value	$ 0.01	$ 0.01
Undesignated stock, shares authorized	20,000,000	20,000,000
Undesignated stock, shares designated	20,000,000	20,000,000
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	100,000,000	50,000,000
Common stock, issued	41,190,905	35,789,388
Common stock, outstanding	41,190,905	35,789,388
Series C 6% super dividend redeemable convertible preferred stock
Convertible preferred stock, shares authorized	1,000	1,000
Convertible preferred stock, shares issued	176	176
Convertible preferred stock, shares outstanding	176	176
Convertible preferred stock, redemption value	$ 8,863,000
Convertible preferred stock, liquidation value	$ 1,786,000
Series A 12% convertible preferred stock
Convertible preferred stock, shares authorized	1,742,500	1,742,500
Convertible preferred stock, issued	1,327,500	1,377,500
Convertible preferred stock, outstanding	1,327,500	1,377,500
Convertible preferred stock, liquidation value	$ 1,367,000
Series B-1 12% convertible preferred stock
Convertible preferred stock, shares authorized	900,000	900,000
Convertible preferred stock, issued	900,000	900,000
Convertible preferred stock, outstanding	900,000	900,000
Convertible preferred stock, liquidation value	$ 1,800,000
Series B-2 12% convertible preferred stock
Convertible preferred stock, shares authorized	2,100,000	2,100,000
Convertible preferred stock, issued	2,100,000	2,100,000
Convertible preferred stock, outstanding	2,100,000	2,100,000
Convertible preferred stock, liquidation value	$ 4,200,000
Series B-3 8% convertible preferred stock
Convertible preferred stock, shares authorized	2,508,000	2,508,000
Convertible preferred stock, issued	2,508,000	2,508,000
Convertible preferred stock, outstanding	2,508,000	2,508,000
Convertible preferred stock, liquidation value	$ 2,508,000

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Operating expenses:
Research and development	$ 6,471	$ 11,721
General and administrative	7,131	4,526
Total operating expenses	13,602	16,247
Total operating loss	(13,602)	(16,247)
Other income (expense):
Interest income	38	24
Interest expense	(336)	(12)
Total other income (expense)	(298)	12
Net loss	(13,900)	(16,235)
Preferred stock dividends	(1,147)	(1,232)
Net loss applicable to common stockholders	$ (15,047)	$ (17,467)
Basic and diluted net loss per share	$ (0.38)	$ (0.49)
Shares used in computing basic and diluted net loss per share	39,414	35,521

Consolidated Statements of Chan

Consolidated Statements of Changes in Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Series A 12% convertible preferred stock	Series B-1 12% convertible preferred stock	Series B-2 12% convertible preferred stock	Series B-3 8% convertible preferred stock	Series C 6% super dividend redeemable convertible preferred stock	Series A 12% convertible preferred stock	Series A 12% convertible preferred stockSeries A 12% convertible preferred stock	Series A 12% convertible preferred stockSeries B-1 12% convertible preferred stock	Series A 12% convertible preferred stockSeries B-2 12% convertible preferred stock	Series A 12% convertible preferred stockSeries B-3 8% convertible preferred stock	Series A 12% convertible preferred stockSeries C 6% super dividend redeemable convertible preferred stock	Series B-1 12% convertible preferred stock	Series B-1 12% convertible preferred stockSeries A 12% convertible preferred stock	Series B-1 12% convertible preferred stockSeries B-1 12% convertible preferred stock	Series B-1 12% convertible preferred stockSeries B-2 12% convertible preferred stock	Series B-1 12% convertible preferred stockSeries B-3 8% convertible preferred stock	Series B-1 12% convertible preferred stockSeries C 6% super dividend redeemable convertible preferred stock	Series B-2 12% convertible preferred stock	Series B-2 12% convertible preferred stockSeries A 12% convertible preferred stock	Series B-2 12% convertible preferred stockSeries B-1 12% convertible preferred stock	Series B-2 12% convertible preferred stockSeries B-2 12% convertible preferred stock	Series B-2 12% convertible preferred stockSeries B-3 8% convertible preferred stock	Series B-2 12% convertible preferred stockSeries C 6% super dividend redeemable convertible preferred stock	Series B-3 8% convertible preferred stock	Series B-3 8% convertible preferred stockSeries A 12% convertible preferred stock	Series B-3 8% convertible preferred stockSeries B-1 12% convertible preferred stock	Series B-3 8% convertible preferred stockSeries B-2 12% convertible preferred stock	Series B-3 8% convertible preferred stockSeries B-3 8% convertible preferred stock	Series B-3 8% convertible preferred stockSeries C 6% super dividend redeemable convertible preferred stock	Common Stock	Common StockSeries A 12% convertible preferred stock	Common StockSeries B-1 12% convertible preferred stock	Common StockSeries B-2 12% convertible preferred stock	Common StockSeries B-3 8% convertible preferred stock	Common StockSeries C 6% super dividend redeemable convertible preferred stock	Additional Paid-In Capital	Additional Paid-In CapitalSeries A 12% convertible preferred stock	Additional Paid-In CapitalSeries B-1 12% convertible preferred stock	Additional Paid-In CapitalSeries B-2 12% convertible preferred stock	Additional Paid-In CapitalSeries B-3 8% convertible preferred stock	Additional Paid-In CapitalSeries C 6% super dividend redeemable convertible preferred stock	Retained Deficit	Retained DeficitSeries A 12% convertible preferred stock	Retained DeficitSeries B-1 12% convertible preferred stock	Retained DeficitSeries B-2 12% convertible preferred stock	Retained DeficitSeries B-3 8% convertible preferred stock	Retained DeficitSeries C 6% super dividend redeemable convertible preferred stock
Stockholders' Equity (Deficit), Balance (in shares) at Dec. 31, 2016							1,377,500						900,000						2,100,000						2,508,000						32,912,942
Stockholders' Equity (Deficit), Balance at Dec. 31, 2016	$ 10,292						$ 557						$ 1,761						$ 3,697						$ 1,224						$ 33						$ 166,721						$ (163,701)
Temporary Equity, Balance (in shares) at Dec. 31, 2016						176
Temporary Equity, Balance at Dec. 31, 2016						$ 1,723
Convertible preferred stock dividend																																						$ 62	$ 257	$ 599	$ 237	$ 77		$ (62)	$ (257)	$ (599)	$ (237)	$ (77)
Convertible preferred stock dividend (in shares)																																27,550	103,691	241,945	95,998	35,200
Issuance of common stock	3,383																														$ 3						3,380
Issuance of common stock (in shares)																															2,213,360
Issuance of common stock and warrants in private placements	200																																				200
Issuance of common stock and warrants in private placements (in shares)																															102,368
Issuance of common stock for services	33																																				33
Issuance of common stock for services (in shares)																															18,677
Issuance of restricted common stock to directors	4																																				4
Issuance of restricted common stock to directors (in shares)																															37,657
Issuance of warrants in connection with line of credit	$ 696																																				696
Issuance of common stock for stock option exercises ( in shares)	0
Stock-based compensation expense	$ 1,097																																				1,097
Net loss	(16,235)																																										(16,235)
Temporary Equity, Balance (in shares) at Dec. 31, 2017						176
Temporary Equity, Balance at Dec. 31, 2017						$ 1,723
Stockholders' Equity (Deficit), Balance (in shares) at Dec. 31, 2017							1,377,500						900,000						2,100,000						2,508,000						35,789,388
Stockholders' Equity (Deficit), Balance at Dec. 31, 2017	(530)						$ 557						$ 1,761						$ 3,697						$ 1,224						$ 36						173,363						(181,168)
Convertible preferred stock dividend			$ (55)	$ (127)	$ (50)																																	$ 146	$ 155	$ 363	$ 144	$ 107		$ (146)	$ (210)	$ (490)	$ (194)	$ (107)
Convertible preferred stock dividend (in shares)																																27,126	27,835	64,948	25,769	20,394
Issuance of common stock	5,603																														$ 1						5,602
Issuance of common stock (in shares)																															669,714
Issuance of common stock and warrants in private placements	6,003																														$ 2						6,001
Issuance of common stock and warrants in private placements (in shares)																															2,455,595
Issuance of common stock for services	12																																				12
Issuance of common stock for services (in shares)																															2,883
Issuance of common stock for stock option exercises	$ 3,773																														$ 2						3,771
Issuance of common stock for stock option exercises ( in shares)	2,098,829																														2,098,829
Issuance of common stock from Series A conversion							$ (20)																														20
Issuance of common stock from Series A conversion (in shares)							(50,000)																								8,424
Stock-based compensation expense	4,445																																				4,445
Net loss	(13,900)																																										(13,900)
Temporary Equity, Balance (in shares) at Dec. 31, 2018						176
Temporary Equity, Balance at Dec. 31, 2018						$ 1,723
Stockholders' Equity (Deficit), Balance (in shares) at Dec. 31, 2018							1,327,500						900,000						2,100,000						2,508,000						41,190,905
Stockholders' Equity (Deficit), Balance at Dec. 31, 2018	$ 5,175						$ 537						$ 1,761						$ 3,697						$ 1,224						$ 41						$ 194,130						$ (196,215)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (13,900)	$ (16,235)
Adjustments to reconcile net loss to net cash from operating activities:
Depreciation and amortization	0	1
Stock-based compensation expense	4,445	1,101
Issuance of common stock for services	12	33
Non-cash interest expense	336	12
Changes in operating assets and liabilities:
Prepaid expenses and other assets	19	8
Accounts payable and accrued expenses	(1,091)	(812)
Net cash from operating activities	(10,179)	(15,892)
CASH FLOWS FROM INVESTING ACTIVITIES:
Net cash from investing activities	0	0
CASH FLOWS FROM FINANCING ACTIVITIES:
Net proceeds from issuance of common stock and warrants	15,379	3,583
Net cash from financing activities	15,379	3,583
NET DECREASE IN CASH AND CASH EQUIVALENTS	5,200	(12,309)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	3,053	15,362
CASH AND CASH EQUIVALENTS, END OF PERIOD	8,253	3,053
NONCASH FINANCING ACTIVITIES:
Payment of preferred stock dividends in common stock	915	1,232
Common stock purchase warrants issued in connection with line of credit	$ 0	$ 696

Nature of Business and Basis of

Nature of Business and Basis of Presentation	12 Months Ended
	Dec. 31, 2018
Nature of Business and Basis of Presentation	1. Nature of Business and Basis of Presentation Galectin Therapeutics Inc. and subsidiaries (the “Company”) is a clinical stage biopharmaceutical company that is applying its leadership in galectin science and drug development to create new therapies for fibrotic disease and cancer. These candidates are based on the Company’s targeting of galectin proteins which are key mediators of biologic and pathologic function. These compounds also may have application for drugs to treat other diseases and chronic health conditions. The Company was founded in July 2000, was incorporated in the State of Nevada in January 2001 under the name “Pro-Pharmaceuticals, Inc.,” and changed its name to “Galectin Therapeutics Inc.” on May 26, 2011. On March 23, 2012, the Company effected a one-for-six reverse stock split. All common share and per share amounts in these financial statements have been adjusted to reflect the effect of the reverse split. The Company has operated at a loss since its inception and has had no revenues. The Company anticipates that losses will continue for the foreseeable future. At December 31, 2018, the Company had $8,253,000 of unrestricted cash and cash equivalents available to fund future operations. Additionally, the Company generated approximately $1.87 100 The Company is subject to a number of risks similar to those of clinical stage companies, including dependence on key individuals, uncertainty of product development and generation of revenues, dependence on outside sources of capital, risks associated with clinical trials of products, dependence on third-party collaborators for research operations, need for regulatory approval of products, risks associated with protection of intellectual property, and competition with larger, better-capitalized companies. Successful completion of the Company’s development program and, ultimately, the attainment of profitable operations is dependent upon future events, including obtaining adequate financing to fulfill its development activities and achieving a level of revenues adequate to support the Company’s cost structure. There are no assurances that the Company will be able to obtain additional financing on favorable terms, or at all, or successfully market its products.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies The accompanying consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States (“GAAP”). Basis of Consolidation. The consolidated financial statements include the accounts of the Company and Galectin Therapeutics Security Corp., its wholly-owned subsidiary, which was incorporated in Delaware on December 23, 2003 and Galectin Sciences LLC (see Note 11). All intercompany transactions have been eliminated. Use of Estimates. The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and judgments that may affect the reported amounts of assets, liabilities, equity, revenue, expenses and related disclosure of contingent assets and liabilities. Management’s estimates and judgments include assumptions used in stock option and warrant liability valuations, useful lives of property and equipment and intangible assets, accrued liabilities, deferred income taxes and various other assumptions that are believed to be reasonable under the circumstances. Actual results may differ from those estimates under different assumptions or conditions. Fair Value Measurements . The Company has certain financial assets and liabilities recorded at fair value. Fair values determined by Level 1 inputs utilize observable data such as quoted prices in active markets. Fair values determined by Level 2 inputs utilize data points other than quoted prices in active markets that are observable either directly or indirectly. Fair values determined by Level 3 inputs utilize unobservable data points in which there is little or no market data, which require the reporting entity to develop its own assumptions. The estimated value of accounts payable and accrued expenses approximates their carrying value due to their short-term nature. There were no Level 2 or 3 assets or liabilities at December 31, 2018 or 2017. Cash and Cash Equivalents. The Company considers all highly-liquid investments with original maturities of 90 days or less at the time of acquisition to be cash equivalents. The Company had no cash equivalents at December 31, 2018 or 2017. Prepaid Expenses and Other Current Assets. Prepaid expenses and other assets consist principally of prepaid insurance and deferred financing costs (see Note 8). Property and Equipment. Property and equipment, including leasehold improvements, are stated at cost, net of accumulated depreciation and amortization, and are depreciated or amortized using the straight-line method over the estimated useful lives of the related assets of generally three five Security Deposit. At December 31, 2018 and 2017, the Company had a security deposit of $6,000 for leased office space included in Prepaid Expenses and Other Current Assets. Intangible Assets. Intangible assets include patent costs, consisting primarily of related capitalized legal fees, which are amortized over an estimated useful life of five Long-Lived Assets. The Company reviews all long-lived assets for impairment whenever events or circumstances indicate the carrying amount of such assets may not be recoverable. Recoverability of assets to be held or used is measured by comparison of the carrying value of the asset to the future undiscounted net cash flows expected to be generated by the asset. If such asset is considered to be impaired, the impairment recognized is measured by the amount by which the carrying value of the asset exceeds the discounted future cash flows expected to be generated by the asset. Accrued Expenses . As part of the process of preparing our consolidated financial statements, we are required to estimate accrued expenses. This process involves identifying services that third parties have performed on our behalf and estimating the level of service performed and the associated cost incurred on these services as of each balance sheet date in our consolidated financial statements. Examples of estimated accrued expenses include contract service fees in conjunction with clinical trials, professional service fees, such as those arising from the services of attorneys and accountants and accrued payroll expenses. In connection with these service fees, our estimates are most affected by our understanding of the status and timing of services provided relative to the actual services incurred by the service providers. In the event that we do not identify certain costs that have been incurred or we under- or over-estimate the level of services or costs of such services, our reported expenses for a reporting period could be understated or overstated. The date on which certain services commence, the level of services performed on or before a given date, and the cost of services are often subject to our judgment. We make these judgments based upon the facts and circumstances known to us in accordance with accounting principles generally accepted in the U.S. Warrants. The Company has issued common stock warrants in connection with the execution of certain equity and debt financings. The fair value of warrants is determined using the Black-Scholes option-pricing model using assumptions regarding volatility of our common share price, remaining life of the warrant, and risk-free interest rates at each period end. There were no warrant liabilities as of December 31, 2018 or 2017. Research and Development Expenses. Costs associated with research and development are expensed as incurred. Research and development expenses include, among other costs, salaries and other personnel-related costs, and costs incurred by outside laboratories and other accredited facilities in connection with clinical trials and preclinical studies. Income Taxes. The Company accounts for income taxes in accordance with the accounting rules that requires an asset and liability approach to accounting for income taxes based upon the future expected values of the related assets and liabilities. Deferred income tax assets and liabilities are determined based on the differences between the financial reporting and tax bases of assets and liabilities and for tax loss and credit carry forwards and are measured using the expected tax rates estimated to be in effect when such basis differences reverse. Valuation allowances are established, if necessary, to reduce the deferred tax asset to the amount that will, more likely than not, be realized. Concentration of Credit Risk. Financial instruments that subject the Company to credit risk consist of cash and cash equivalents and certificates of deposit. The Company maintains cash and cash equivalents and certificates of deposit with well-capitalized financial institutions. At times, those amounts may exceed federally insured limits. The Company has no significant concentrations of credit risk. Stock-Based Compensation. Stock-based compensation cost is measured at the grant date based on the fair value of the award and is recognized as expense over the service period, which generally represents the vesting period. For awards that have performance-based vesting conditions the Company recognizes the expense over the estimated period that the awards are expected to be earned. The Company generally uses the Black-Scholes option-pricing model to calculate the grant date fair value of stock options. For options that only vest upon the achievement of market conditions, the Company values the options using a Monte Carlo model to calculate the grant date fair value of the stock options. The expense related to options that vest based on market conditions is not reversed should those options not ultimately vest. The expense recognized over the service period is required to include an estimate of the awards that will be forfeited. Stock options issued to non-employees are accounted for in accordance with the provisions of ASC Subtopic 505-50, Equity-Based Payments to Non-employees , which requires valuing the stock options using an option pricing model (the Company uses Black-Scholes) and measuring such stock options to their current fair value when they vest. New Accounting Pronouncements. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) , which requires lessees to recognize the most leases on the balance sheet. The provisions of this guidance are effective for the annual periods beginning after December 15, 2018, and interim periods within those years, with early adoption permitted. The Company is evaluating the requirements of this guidance and has not yet determined the impact of the adoption on our financial position or results of operations.

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2018
Property and Equipment	3. Property and Equipment Property and equipment consist of the following at December 31: 2018 2017 (in thousands) Leasehold improvements $ 2 $ 2 Computer and office equipment 13 13 Furniture and fixtures 59 59 Total 74 74 Less accumulated depreciation and amortization (74 ) (74 ) Property and equipment — net $ — $ — Depreciation and amortization expense for the years ended December 31, 2018 and 2017 was $0 and $0, respectively.

Accrued Expenses

Accrued Expenses	12 Months Ended
	Dec. 31, 2018
Accrued Expenses	4. Accrued Expenses Accrued expenses consist of the following at December 31: 2018 2017 (in thousands) Legal and accounting fees $ 45 $ 74 Accrued compensation 1,294 790 Accrued research and development costs and other 173 1,428 Total $ 1,512 $ 2,292

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2018
Stockholders' Equity	5. Stockholders’ Equity At December 31, 2018, the Company had 100,000,000 shares of common stock and 20,000,000 undesignated shares authorized. As of December 31, 2018, 1,742,500 shares have been designated for Series A 12% Convertible Preferred Stock, 900,000 shares have been designated for Series B-1 Convertible Preferred Stock, 2,100,000 shares have been designated for Series B-2 Convertible Preferred Stock, 1,000 shares have been designated for Series C Super Dividend Convertible Preferred Stock, 2,508,000 shares have been designated for Series B-3 Convertible Preferred Stock, 12,748,500 have been designated as common stock and no shares remain undesignated. At Market Issuances of Common Stock On March 30, 2014, the Company entered into an At Market Issuance Sales Agreement (the “2014 At Market Agreement”) with a sales agent under which the Company may issue and sell shares of its common stock having an aggregate offering price of up to $30.0 million from time to time through the sales agent. Sales of the Company’s common stock through the sales agent, if any, will be made by any method that is deemed an “at the market” offering as defined by the U.S. Securities and Exchange Commission. The Company will pay to the sales agent a commission rate equal to 3.0% of the gross proceeds from the sale of any shares of common stock sold through the sales agent under the 2014 At Market Agreement. In 2017, the Company issued 1,496,797 shares of common stock for net proceeds of approximately $1,946,000 under the 2014 At Market Agreement. On May 19, 2017, the Company entered into an At Market Issuance Sales Agreement (the “2017 At Market Agreement”) with a sales agent under which the Company may issue and sell shares of its common stock having an aggregate offering price of up to $30.0 million from time to time through the sales agent. Sales of the Company’s common stock through the sales agent, if any, will be made by any method that is deemed an “at the market” offering as defined by the U.S. Securities and Exchange Commission. The Company will pay to the sales agent a commission rate equal to 3.0% of the gross proceeds from the sale of any shares of common stock sold through the sales agent under the 2017 At Market Agreement. During the years ended December 31, 2018 and 2017, the Company issued 669,714 and 716,563 shares of common stock for net proceeds of approximately $5,603,000 and $1,437,000, respectively, under the 2017 At Market Agreement. 2017 Private Placement On February 28, 2017, the Company closed a transaction with five individual investors through a private placement of common stock and warrants. In total, the Company issued 102,368 shares of common stock for proceeds of $200,000. The Company also issued, to the five investors, warrants to purchase 76,776 shares of common stock at $5.00 per share. The warrants have an expiration date of February 28, 2024. The exercise price of each warrant is adjustable in the event of a stock split or stock combination, capital reorganization, merger or similar event. The warrants were valued at approximately $101,000 as of the issuance, using the closing price of $1.86, a life of 7 years, a volatility of 97% and a risk-free interest rate of 1.92%. Based upon the Company’s analysis of the criteria contained in ASC Topic 815-40, “Derivatives and Hedging — Contracts in Entity’s Own Equity” the Company has determined that warrants issued in connection with this financing transaction were not derivative liabilities and therefore, were recorded as additional paid-in capital. Other In 2017, the Company entered an agreement with a vendor whereby the Company will issue common stock to the vendor in lieu of paying in cash in amount up to $100,000 for the year. In 2018 and 2017, the Company issued 2,883 and 18,667 shares of common stock and 290 and 1,867 warrants to purchase shares of common stock at $5.00 per share pursuant to this agreement and the value of such shares and warrants, totaling approximately $12,000 and $33,000, respectively, has been recorded as research and development expense. Series A 12% Convertible Preferred Stock — February 4, 2008 Private Placement On February 4, 2008, the Company closed a private placement begun in October 2007 of its Series A 12% Convertible Preferred Stock (“Series A”) and related warrants. In this transaction, the Company sold units of securities at $6.00 per unit, each unit comprised of (i) one share of Series A Preferred, (ii) a warrant to purchase one share of common stock for $9.00, and (iii) a warrant to purchase one share of common stock for $12.00. Each share of the Series A is entitled to dividends at the rate of 12% per annum payable at the Company’s option in cash or shares of common stock valued at the higher of $6.00 per share or 100% of the value weighted average price of the Company’s share price for the 20 consecutive trading days prior to the applicable dividend payment date. Dividends are payable semi-annually on March 30 and September 30. The dividend paid on the initial dividend payment date is calculated from the date the Company deposited each subscription advance. The shares of Series A are entitled to vote as a class with the Company’s common stock and each share of Series A is convertible at any time to one-sixth of a share of common stock, subject to adjustment in the event of a stock dividend, stock split or combination, reclassification or similar event. The Company has the right to require conversion if the closing price of the common stock exceeds $18.00 for 15 consecutive trading days and a registration statement covering the resale of the shares of common stock issuable upon conversion of the Series A is then in effect. Each warrant is exercisable solely for cash beginning August 3, 2008 and expired on February 4, 2012. The exercise price of each warrant is adjustable in the event of a stock split or stock combination, capital reorganization, merger or similar event. In 2018, 50,000 shares of Series A were converted into 8,424 shares of common stock which included 90 shares relating to the prorated dividend prior conversion. There were no shares of Series A converted into shares of common stock in 2017. Prior to 2016, a total of 360,000 shares of Series A had been converted into 60,888 shares of common stock. Series B Convertible Preferred Stock (also see Note 13 Subsequent Events) On February 12, 2009, the Company entered into a securities purchase agreement (the “10X Agreement”) pursuant to which it agreed to issue and sell to 10X Fund LP, at two or more closings, up to: (i) 3,000,000 shares its Series B-1 and B-2 convertible preferred stock with an aggregate stated value of $6.0 million and convertible into 2,000,000 shares of common stock at December 31, 2011 and (ii) warrants to purchase 6,000,000 shares of common stock. Through a series of closings from February 2009 through May 2010, the Company issued and sold, pursuant to the 10X Agreement, a total of (i) 900,000 shares of Series B-1 convertible preferred stock (“Series B-1 convertible preferred stock” or “Series B-1”) and related common stock warrants for 1,800,000 shares of common stock and (ii) 2,100,000 shares of Series B-2 convertible preferred stock (“Series B-2 convertible preferred stock” or “Series B-2”) and related warrants for 4,200,000 shares of common stock for total net proceeds of $5,483,000. On September 22, 2016, the Company entered into a securities purchase agreement (the “B-3 Agreement”) pursuant to which it agreed to issue and sell to 10X Fund LP: (i) 1,500,000 shares its Series B-3 convertible preferred stock (“Series B-3 preferred stock” or “Series B-3”) with an aggregate stated value and proceeds of $1.5 million and convertible into 892,349 shares of common stock, and (ii) warrants to purchase up to 669,262 shares of common stock. Also, pursuant to agreements signed on September 22, 2016 with 10X Fund LP, the Company issued 875,000 warrants to purchase common stock in exchange in exchange for the 10X Fund LP agreeing not to sell any shares of common or preferred stock in the Company for 18 months, except in limited circumstances. Additionally, as previously agreed to by the 10X Fund LP, the sole holder of the Company’s Series B-1, Series B-2 and Series B-3 preferred stock (collectively, with the Series B-1 and Series B-2, the “Series B”), in the Second Amended and Restated Certificate of Designation of Preferences, Rights and Limitations of Series B preferred stock we removed the ability of the holders of the Series B to cause a redemption of their shares of Series B. Accordingly, the Company accounted for the removal of this redemption feature as a modification and reclassified the Series B-1 and Series B-2 preferred stock into permanent equity at September 30, 2016 and forward. On December 23, 2016, the Company and 10X Fund LP amended the B-3 Agreement whereby the Company agreed to issue and sell to 10X Fund LP an additional (i) 1,008,000 shares of its B-3 preferred stock with an aggregate stated value and proceeds of $1.0 million and convertible into 896,997 shares of common stock, and (ii) warrants to purchase up to 924,780 shares of common stock. The terms of the Series B are as follows: Dividends . Holders of the Series B will be entitled to receive cumulative dividends at the rate of 12% for Series B-1 and B-2 and 8% for Series B-3 per annum (compounding monthly) payable quarterly which may, at the Company’s option, be paid in cash or common stock. Pursuant to an agreement with the holder of all shares of Series B, on January 26, 2011, the Company amended and restated the Certificate of Designation of Preferences, Rights and Limitations for the Series B-1 and Series B-2, to provide that dividends are payable in cash or shares of Common Stock valued at 100% of the volume weighted average price of the Common Stock for the 20 consecutive trading days prior to the dividend payment date on and after September 30, 2011. If the Company does not pay any dividend on the Series B, dividends will accrue at the rate of 15% per annum (compounding monthly). Conversion Rights . Each share of Series B-1 and B-2 is convertible into two-thirds (approximately 0.667) shares of common stock at the conversion price of $3.00 per share at the option of the holder, at any time. The shares of Series B-3 are convertible into 1,789,346 shares of common stock at the option of the holder, at any time. Liquidation Rights . In the event of any liquidation, dissolution or winding up of the Company, either voluntarily or involuntarily, the holders of Series B-1 and B-2 will receive $2 per share and holders of B-3 will receive $1 per share plus accrued and unpaid dividends, payable prior and in preference to any distributions to the holders of Common Stock but pari passu with the holders of the Series A 12% Convertible Preferred Stock. Voting Rights . Except as noted below, the holder of each share of Series B-3 shall be entitled to the number of votes equal to the number of shares of Common Stock into which such share of Series B-3 would be convertible, and shall otherwise have voting rights and powers equal to the voting rights and powers of the Common Stock. With respect to the election of directors, the holders of the Series B-3, together with the holders of Series B-1 and Series B-2, shall vote together as a separate class to elect two (2) members of the Board of Directors (the “Series B Directors”), and the Company shall take all reasonably necessary or desirable actions within its control (including, without limitation, calling special meetings of the Board of Directors, nominating such persons designated by the holders of the Series B as directors on the applicable proxy statements and recommending their election) to permit the holders of the Series B to appoint three additional (3) members of the Board of Directors (the “Series B Nominees”), who shall be subject to election by all shares of voting stock of the Company voting together as a single group,) until there are no longer any shares of Series B outstanding. The holders of Series B shall vote together with the holders of Common Stock and other voting capital stock of the Company to elect all other members of the Board of Directors. Other Restrictions . So long as any shares of the Series B remain outstanding, the Company may not, without the approval of the holders of a majority of the shares of Series B outstanding, among other things, (i) change the size of the Company’s Board of Directors; (ii) amend or repeal the Company’s Articles of Incorporation or Bylaws or file any articles of amendment designating the preferences, limitations and relative rights of any series of preferred stock, that would alter or change the preferences, rights, privileges or powers of, or restriction provided for the benefit of the Series B; (iii) create or increase the authorized amount of any additional class or series of shares of stock that is equal to or senior to Series B; (iv) increase or decrease the authorized number of shares of the Series B; (v) purchase, redeem or otherwise acquire for value any shares of any class of capital stock; (vi) merge or consolidate the Company into or with any other corporation or sell, assign, lease, pledge, encumber or otherwise dispose of all or substantially all of the Company’s assets or those of any subsidiary; (vii) voluntarily or involuntarily liquidate, dissolve or wind up the Company or the Company’s business; (viii) pay or declare dividends on any capital stock other than the Preferred Stock, unless the Series B share ratably in such dividend and all accrued dividends payable with respect to the Series B have been paid prior to the payment or declaration of such dividend; (ix) acquire an equitable interest in, or the assets or business of any other entity in any form of transaction; (x) create or commit us to enter into a joint venture, licensing agreement or exclusive marketing or other distribution agreement with respect to the Company’s products, other than in the ordinary course of business; (xi) permit the Company or any subsidiary to sell or issue any security of such subsidiary to any person or entity other than the Company; (xii) enter into, create, incur, assume or guarantee any indebtedness for borrowed money of any kind (other than indebtedness existing on the initial closing date and approved by Series B shareholders); (xiii) enter into, create, incur or assume any liens of any kind (other than certain permitted liens); (xiv) issue any common stock or common stock equivalents; (xv) increase the number of shares of the Company’s common stock that may be issued pursuant to options, warrants or rights to employees, directors, officers, consultants or advisors above the number of shares that were authorized for issuance under our 2001 Stock Incentive Plan, 2003 Non-Employee Director Stock Incentive Plan and 2009 Incentive Compensation Plan as of September 9, 2016. Warrants . Each Series B-1 or B-2 related warrant is exercisable at $3.00 per share of common stock at any time on or after the date of issuance until the fifth anniversary of the respective issue date. The Company may, upon 30 days’ notice and so long as an effective registration statement regarding the underlying shares of common stock is in effect, issue a termination notice with respect to (i) each Class A-1 warrant on any trading day on which the market value of the common stock for each of the 15 previous trading days exceeded $7.50 per share and (ii) each Class A-2 warrant on any trading day on which the market value of the common stock for each of the 15 previous trading days exceeded $10.50 per share. All Class A-1 warrants were exercised for cash proceeds of $3,000,000 in 2011 and 500,000 of the Class A-2 warrants were exercised for cash proceeds of $1,500,000 in 2013. Subsequently, in January 2014, the remaining 500,000 Class A-2 warrants were exercised for cash proceeds of $1,500,000. The fair value of the warrants issued in connection with the Series B-1 was $1,296,000 at the date of issuance based on the following assumptions: an expected life of 5 years, volatility of 118%, risk free interest rate of 1.79% and zero dividends. The Company allocated the gross proceeds based on the relative fair value of the Series B-1 and the related warrants, resulting in $1,105,000 The fair value of the warrants issued during the year ended December 31, 2010 in connection with the Series B-2 was $4,148,000 at the dates of issuance based on the following assumptions: an expected life of 5 years, volatility of 126% to 129%, risk free interest rates of 2.27% to 2.43% and zero dividends. The fair value of the warrants issued during the year ended December 31, 2009 in connection with the Series B-2 was $5,333,000 at the dates of issuance based on the following assumptions: an expected life of 5 years, volatility of 124% to 127%, risk free interest rates of 1.98% to 2.70% and zero dividends. The Company allocated the gross proceeds based on the relative fair value of the Series B-2 and the related warrants, resulting in $1,028,000 and $1,732,000 of the proceeds being allocated to additional paid-in capital for the years ended December 31, 2010 and 2009, respectively. The issuance costs of the Series B-2 and the amounts allocated to warrants were recorded as a reduction to the carrying value of the Series B-2 when issued, and are accreted to the redemption value of the Series B-2 through the earliest redemption dates. The Company analyzed the Series B- , post-allocation of the gross proceeds, and determined that there was a beneficial conversion feature at the dates of issuance. Because the closing price of the common stock on the closing date was greater than the effective conversion price, $ and $ of the proceeds (limited to the allocation of the proceeds) during the years ended December , and , respectively, were allocated to an embedded beneficial conversion feature of the Series B- . The amount allocated to the beneficial conversion feature was recorded as a discount to the Series B- is being accreted, with such accretion being charged through the earliest redemption dates. As noted above, the Series B- preferred was reclassified to permanent equity as of September , and forward and accretion was ended. All warrants issued in the Series B-3 transaction are exercisable at $3.00 per share of common stock at any time on or after the date of issuance until the seventh anniversary of the respective issue date. The fair value of the warrants issued in connection with the September 22, 2016, Series B-3 was $2,262,000 at the date of issuance based on the following assumptions: an expected life of 7 years, volatility of 95%, risk free interest rate of 1.42% and zero dividends. The Company allocated the gross proceeds of $1.5 million based on the relative fair value of the Series B-3 and the related warrants, resulting in $890,000 of the proceeds being allocated to additional paid-in capital and $610,000 being allocated to the Series B-3. The Company analyzed the September 22, 2016, Series B-3, post-allocation of the gross proceeds, and determined that there was a beneficial conversion feature at the dates of issuance. Because the closing price of the common stock on the closing date was greater than the effective conversion price, an embedded beneficial conversion feature of the Series B-3 amounting to $991,000 was charged to additional paid in capital and accumulated deficit. The fair value of the warrants issued in connection with the December 23, 2016, Series B-3 was $658,000 at the date of issuance based on the following assumptions: an expected life of 7 years, volatility of 96%, risk free interest rate of 2.35% and zero dividends. The Company allocated the gross proceeds of $1.008 million based on the relative fair value of the Series B-3 and the related warrants, resulting in $394,000 of the proceeds being allocated to additional paid-in capital and $614,000 being allocated to the Series B-3. The Company analyzed the December 23, 2016, Series B-3, post-allocation of the gross proceeds, and determined that there was a beneficial conversion feature at the dates of issuance. Because the closing price of the common stock on the closing date was greater than the effective conversion price, an embedded beneficial conversion feature of the Series B-3 amounting to $310,000 was charged to additional paid in capital and accumulated deficit. Series C 6% Super Dividend Redeemable Convertible Preferred Stock On December 29, 2010, the Company designated and authorized the sale and issuance of up to 1,000 shares of Series C Super Dividend Redeemable Convertible Preferred Stock (“Series C”) with a par value of $0.01 and a stated value equal to $10,000 (the “Stated Value”). On December 30, 2010, the Company sold and issued 212 shares of Series C at a price of $10,000 per share for gross proceeds of $2,120,000. The Company incurred $47,000 of cash transaction costs resulting in net cash proceeds of $2,073,000. In addition, the Company issued 500 warrants exercisable at $7.20 to a placement agent which had a de minimis value. Additionally, in January 2011, the Company sold and issued 13 shares of Series C at a price of $10,000 per share for gross proceeds of $130,000. The terms of the Series C are as follows: Conversion Rights . Each holder of Series C may convert all, but not less than all, of his Series C shares plus accrued and unpaid dividends into Common Stock at the price of $6.00 per share of Common Stock (“Conversion Price”), such that approximately 1,667 shares of Common Stock will be issued per each converted share of Series C (accrued and unpaid dividends will be issued as additional shares). At December 31, 2018 and 2017, the 176 outstanding shares of Series C were convertible into a total of approximately 293,340 shares of Common Stock. Subject to the continuing obligation to pay post conversion dividends, the Company may convert all, but not less than all, of the Series C (plus all accrued and unpaid dividends) into Common Stock, at the Conversion Price, upon such time that the closing price of the Common Stock is no less than $18.00 per share for 15 consecutive trading days. Dividends ® The dividend shall be payable in arrears semiannually on March 31 and September 30, beginning with the first such date after the original issue date; provided, however, that all dividends and all other distributions shall cease, and no further dividends or other distributions shall be paid, in respect of each share of Series C from and after such time that the Maximum Payout has been paid in respect of such share of Series C. Such dividends shall be payable at the Company’s option either in cash or in duly authorized, fully paid and non-assessable shares of Common Stock valued at the higher of (i) $3.00 per share or (ii) the average of the Common Stock trading price for the ten (10) consecutive trading days ending on the trading day that is immediately prior to the dividend payment date. Series C Post Conversion Dividend Right . In the event that any share of Series C is converted into Common Stock before the Maximum Payout is paid in respect of such converted share of Series C, then the holder shall have the right to continue to receive dividends in respect of such converted share of Series C equal to the remaining payout (the “Series C Preferred Stock Post Conversion Dividend Right”) which shall be equal to the Maximum Payout less the cumulative dividends received through the conversion date. One share of Series C Preferred Stock Post Conversion Dividend Right shall be issued for each such converted share of Series C. The holder of each Series C Preferred Stock Post Conversion Dividend Right shall receive the remaining payout on an equal basis and in conjunction with the then outstanding shares of Series C and all the other then outstanding Series C Post Conversion Dividend Rights, in the same manner and subject to the same terms and conditions as applicable to the payment of dividends on each share of Series C, except that for purposes of calculating the dividend the Floor shall not apply. The Series C Preferred Stock Post Conversion Dividend Right shall have no stated value, liquidation preference or right to any dividends or distributions other than the remaining payout. The Series C Preferred Stock Post Conversion Right is subject to redemption in the same manner as outstanding Series C shares. At the date of issuance, the Series C have an embedded dividend right to continue to receive dividend payments after conversion to common stock (the Series C Post Conversion Dividend Right) which requires bifurcation. The value of this post conversion dividend right on the date of issuance was determined to be de minimis due to the fact that the payment of a dividend stream other than the 6% dividend and conversion of Series C prior to the Company achieving sales of GM-CT-01 was deemed improbable at that time. Upon a conversion of the Series C, the Company will be required to record a liability and the related expense during the period of conversion. In July 2011, 5 shares of Series C were converted into 8,334 shares of common stock and 5 Series C Post Conversion Dividend Rights (Dividend Rights) were issued. In 2013, 24 shares of Series C were converted into 40,193 shares of common stock and 24 Dividend Rights were issued. In 2014, 20 shares of Series C were converted into 33,756 shares of common stock and 20 Dividend Rights were issued. Per the terms of the Series C, these Dividend Rights shall continue to participate in dividends, however the Floor shall not apply. At December 31, 2016 and 2015, these Dividend Rights were determined to have a de minimis value, as the payment of a dividend is considered improbable at this time. The Company will continue to evaluate and assess the Series C Post Conversion Dividend Right for each reporting period. Liquidation Rights . In the event of any liquidation, dissolution or winding up of the Company, either voluntarily or involuntarily, the holders of Series C will receive $10,000 per share plus accrued and unpaid dividends, payable prior and in preference to any distributions to the holders of Common Stock but after and subordinate to the Series A 12% Convertible Preferred Stock (“Series A”), Series B-1 and Series B-2, subject to the Maximum Payout. Redemption . Upon a sale of the Company, the Company shall redeem all of the then outstanding shares of Series C and Series C Preferred Stock Post Conversion Rights within thirty (30) days after the transaction constituting the sale of the Company is closed and such closing is fully funded. The price to redeem a share of Series C and each redeemed Series C Preferred Stock Post Conversion Redemption Right shall be equal to (i) (A) the applicable return on investment (“ROI”) percentage, multiplied by (B) $10,000, minus (ii) the cumulative dividends received through the redemption date. The redemption price shall be payable at the Company’s option either in cash or in shares of common stock valued at the higher of (i) $3.00 per share or (ii) the average market price for the ten consecutive trading days ending immediately prior to the date of redemption. The ROI Percentage shall mean the percentage that applies as of the redemption date, as follows: ROI Percentage 200% before the second anniversary of the date of issuance; 250% on or after the second anniversary of the date of issuance, but before the third anniversary of the date of issuance; 300% on or after the third anniversary of the date of issuance, but before the fourth anniversary of the date of issuance; 350% on or after the fourth anniversary of the date of issuance, but before the fifth anniversary of the date of issuance; 400% on or after the fifth anniversary of the date of issuance, but before the sixth anniversary of the date of issuance; 450% on or after the sixth anniversary of the date of issuance, but before the seventh anniversary of the date of issuance; 500% on or after the seventh anniversary of the date of issuance, but before the eighth anniversary of the date of issuance; and 550% on or after the eighth anniversary of the date of issuance, but before the ninth anniversary of the date of issuance. Due to the redemption feature, the Company has presented the Series C outside of permanent equity, in the mezzanine of the consolidated balance sheets at December 31, 2018 and 2017. At December 31, 2018, the Series C redemption value was $8,863,000. Voting Rights . The Series C shares have no voting rights.

Warrants

Warrants	12 Months Ended
	Dec. 31, 2018
Warrants	6. Warrants Warrant activity is summarized as follows: Outstanding at December 31, 2016 13,488,296 Issued 1,078,643 Exercised — Canceled (1,337,161 ) Outstanding at December 31, 2017 13,229,778 Issued 290 Exercised (2,583,042 ) Canceled — Outstanding at December 31, 2018 10,647,026 The following table summarizes information with regard to outstanding warrants issued in connection with equity and debt financings and consultants as of December 31, 2018. Issued in Connection With Number Issued Exercise Price Exercisable Date Expiration Date February 12, 2009 Series B-1 Transaction $3.00 Investor Warrants — Class B 1,200,000 $ 3.00 February 12, 2009 February 12, 2019 May 13, 2009 Series B-2 Transaction $3.00 Investor Warrants — Class B 600,000 $ 3.00 May 13, 2009 May 13, 2019 June 30, 2009 Series B-2 Transaction $3.00 Investor Warrants — Class B 333,333 $ 3.00 June 30, 2009 June 30, 2019 August 12, 2009 Series B-2 Transaction $3.00 Investor Warrants — Class B 200,000 $ 3.00 August 12, 2009 August 12, 2019 September 30, 2009 Series B-2 Transaction $3.00 Investor Warrants — Class B 216,666 $ 3.00 September 30, 2009 September 30, 2019 November 4, 2009 Series B-2 Transaction $3.00 Investor Warrants — Class B 106,666 $ 3.00 November 4, 2009 November 4, 2019 December 8, 2009 Series B-2 Transaction $3.00 Investor Warrants — Class B 133,143 $ 3.00 December 8, 2009 December 8, 2019 January 29, 2010 Series B-2 Transaction $3.00 Investor Warrants — Class B 216,667 $ 3.00 January 29, 2010 January 29, 2020 March 8, 2010 Series B-2 Transaction $3.00 Investor Warrants — Class B 223,334 $ 3.00 March 8, 2010 March 8, 2020 April 30, 2010 Series B-2 Transaction $3.00 Investor Warrants — Class B 206,667 $ 3.00 April 30, 2010 April 30, 2020 May 10, 2010 Series B-2 Transaction $3.00 Investor Warrants — Class B 371,667 $ 3.00 May 10, 2010 May 10, 2020 November 25, 2015 Offering Warrants 1,180,240 $ 2.50 May 25, 2016 May 25, 2021 September 22, 2016 Series B-3 Transaction $3.00 Investor Warrants 698,158 $ 3.00 September 22, 2016 September 22, 2023 September 29, 2016 Series B-3 Transaction $3.00 Investor Warrants 846,100 $ 3.00 September 29, 2016 September 29, 2023 December 22, 2016 Private placement warrants 1,466,204 $ 5.00 December 22, 2016 December 23, 2023 December 23, 2016 Series B-3 Transaction $3.00 Investor Warrants 924,780 $ 3.00 December 23, 2016 December 23, 2023 December 28, 2016 Private placement warrants 644,468 $ 5.00 December 28, 2016 December 28, 2023 February 27, 2017 Private placement warrants 76,776 $ 5.00 February 27, 2017 February 27, 2024 2018 and 2017 Warrants issued for services 2,157 $ 5.00 Various dates in 2018 and 2017 Various dates in 2025 and 2024 December 19, 2017 Line of credit warrants 1,000,000 $ 5.00 December 19, 2017 December 19, 2024 Total outstanding warrants 10,647,026 Offering Warrants On March 28, 2012, the Company sold and issued 1,333,361 Units (2,666,722 shares of common stock and related $5.63 warrants to purchase 1,333,361 shares of common stock) for gross proceeds of $12.0 million (net cash proceeds of $10,403,000 after the underwriting discount and offering costs). The warrants were valued at $4,445,000 as of the issuance date of March 28, 2012, using the closing price of $4.20, a life of 5 years, a volatility of 119% and a risk-free interest rate of 1.05%. Based upon the Company’s analysis of the criteria contained in ASC Topic 815-40, “Derivatives and Hedging — Contracts in Entity’s Own Equity” the Company has determined that warrants issued in connection with this financing transaction were not derivative liabilities and therefore, were recorded as additional paid-in capital. The remaining balance of 1,317,161 of these warrants expired on March 28, 2017.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2018
Stock-Based Compensation	7. Stock-Based Compensation Summary of Stock-Based Compensation Plans At December 31, 2018, the Company has a stock-based compensation plan where the Company’s common stock has been made available for equity-based incentive grants as part of the Company’s compensation programs. In February 2009, the Company adopted the 2009 Incentive Compensation Plan (the “2009 Plan”) which originally provided for the issuance of up to 3,333,334, which was subsequently increased to 4,733,334 in May 2014, to 5,733,334 in December 2017, and to 6,733,334 in May 2018 shares of the Company’s common stock in the form of options, stock appreciation rights, restricted stock and other stock-based awards to employees, officers, directors, consultants and other eligible persons. At December 31, 2018, 889,920 shares were available for future grant under the 2009 Plan. In addition, the Company has awarded 1,477,379 non-plan stock option grants to employees and non-employees. These non-plan grants have vesting periods and expiration dates similar to those options granted under the Incentive Plans. At December 31, 2018, 500,000 non-plan grants were outstanding. Stock-Based Compensation Following is the stock-based compensation expense related to common stock options, restricted common stock and common stock warrants: Year Ended December 31, 2018 2017 Research and development $ 1,944 $ 521 General and administrative 2,501 580 Total stock-based compensation expense $ 4,445 $ 1,101 The fair value of the options granted is determined using the Black-Scholes option-pricing model. The following weighted average assumptions were used: 2018 2017 Risk-free interest rate 2.47 % 2.05 % Expected life of the options 5.7 5.5 Expected volatility of the underlying stock 104 % 103 % Expected dividend rate 0 % 0 % As noted above, the fair value of stock options is determined by using the Black-Scholes option pricing model. For all options granted since January 1, 2006 the Company has generally used option terms of between 5 to 10 years, generally with 5 to 6 years representing the estimated life of options granted to employees. The volatility of the common stock is estimated using historical volatility over a period equal to the expected life at the date of grant. The risk-free interest rate used in the Black-Scholes option pricing model is determined by reference to historical U.S. Treasury constant maturity rates with terms equal to the expected terms of the awards. An expected dividend yield of zero The following table summarizes the stock option activity in the stock-based compensation plans: Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Life (in years) Aggregate Intrinsic Value (in thousands) Outstanding, December 31, 2016 4,656,888 $ 4.30 Granted 498,375 2.39 Forfeited/Cancelled — — Exercised — — Outstanding, December 31, 2017 5,155,263 $ 4.11 Granted 1,011,875 5.01 Forfeited/Cancelled (1,354,330 ) 7.31 Exercised (2,098,829 ) 2.00 Outstanding, December 31, 2018 2,713,979 $ 4.67 6.74 $ 1,524 Exercisable, December 31, 2018 2,659,114 $ 4.69 6.69 $ 1,518 The aggregate intrinsic value in the table above represents the total pre-tax amount, net of exercise price, which would have been received by option holders if all option holders had exercised all options with an exercise price lower than the market price on December 31, 2018, based on the closing price of the Company’s common stock of $3.43 on that date. The weighted-average grant-date fair values of options granted during 2018 and 2017 were $3.98 and $1.88, respectively. As of December 31, 2018 and 2017, there were unvested options to purchase 54,865 and 628,584 shares of common stock, respectively. Total expected unrecognized compensation cost related to such unvested options is $83,000 at December 31, 2018, which is expected to be recognized over a weighted-average period of 0.41 years. The aggregate intrinsic value of stock options exercised for the year ended December 31, 2018 was $11,076,199. There were no options exercised during the year ended December 31, 2017. During the years ended December 31, 2018 and 2017, 1,409,804 and 1,142,441 options became vested, respectively. The total grant date fair value of options vested during the years ended December 31, 2018 and 2017 was $4,519,000 and $1,066,000, respectively. The following table summarizes additional information regarding outstanding and exercisable options under our stock-based compensation plans at December 31, 2018: Options Outstanding Options Exercisable Exercise Price (Range) Number of Shares Weighted Average Remaining Contractual Life Weighted Average Exercise Price Number of Shares Weighted Average Exercise Price (in years) $0.87 – 1.00 232,000 7.95 $ 0.88 232,000 $ 0.88 $1.01 – 3.00 854,137 7.35 2.34 851,147 2.34 $3.01 – 5.00 558,392 8.22 3.99 506,517 3.98 $5.01 – 8.00 886,950 5.24 6.55 886,950 6.55 $8.01 – 13.38 182,500 5.06 13.38 182,500 13.38 2,713,979 6.74 $ 4.67 2,659,114 $ 4.68 Restricted Stock Issuances In December 2017, two directors elected to take restricted stock grants in lieu of cash retainers for 2018. A total of 37,657 shares of restricted stock valued at approximately $90,000 was amortized to expense on a straight-line basis until December 14, 2018 when the stock vested in full.

Line of Credit

Line of Credit	12 Months Ended
	Dec. 31, 2018
Line of Credit	8. Line of Credit On December 19, 2017, the Company entered into a $10 million Line of Credit arrangement with Richard E. Uihlein, a director and shareholder who has an approximate 7% ownership interest in the Company on a fully-diluted basis at December 31, 2017. Originally, borrowings may be made by the Company through December 31, 2018. Borrowings bear interest at the Applicable Federal Rate for short term loans published by the Internal Revenue Service (2.7% in January 2019). All borrowings and interest are due on December 31, 2019 but may be prepaid without penalty. In connection with the Line of Credit agreement, the Company issued to Mr. Uihlein warrants to purchase 1 million shares of the Company’s common stock for $5 per share. Half of the warrants vested at closing of the Line of Credit and the other half vest ratably with borrowings under the agreement. There were no borrowings under the Line of Credit during the year ended December 31, 2018 or 2017. On December 20, 2018, the Line of Credit arrangement was extended for one year for both borrowings and maturity. on January 11, 2019, the Line of Credit arrangement was extended for an additional two years for both borrowings and maturity. After the second amendment to the Line of Credit arrangement, borrowings may be made through December 31, 2021 with repayment due on December 31, 2022. There was no additional consideration or benefits provided to Mr. Uihlein for any of the extensions of the Line of Credit. The fair value of the 500,000 warrants vested at closing in December 2017 was $696,000 at the date of issuance based on the following assumptions: an expected life of 7 years, volatility of 98%, risk free interest rate of 2.05% and zero dividends. The fair value of the vested warrants was recorded in other current assets and other assets (non-current) as a deferred financing cost and were to be amortized on a straight-line basis from December 19, 2017 through December 31, 2019. The remaining unamortized balance of the deferred financing cost on December 20, 2018 was adjusted to be recorded as expense on a straight-line basis through December 31, 2020. Amortization for the year ended December 31, 2018 and 2017 of $336,000 and $12,000, respectively, was recorded as interest expense. The fair value of warrants that vest in the future based on borrowings will be computed when those borrowings occur and amortized over the remaining period through December 31, 2022 reflecting the second extension.

Loss Per Share

Loss Per Share	12 Months Ended
	Dec. 31, 2018
Loss Per Share	9. Loss Per Share Basic net loss per common share is computed by dividing the net loss available to common stockholders by the weighted average number of common shares outstanding during the period. Diluted net loss per common share is computed by dividing the net loss available to common stockholders by the weighted average number of common shares and other potential common shares then outstanding. Potential common shares consist of common shares issuable upon the assumed exercise of in-the-money stock options and warrants and potential common shares related to the conversion of the preferred stock. The computation of diluted net loss per share does not assume the issuance of common shares that have an anti-dilutive effect on net loss per share. Year Ended December 31, (in thousands, except per share amounts) 2018 2017 Net loss $ (13,900 ) $ (16,235 ) Preferred stock dividends (1,147 ) (1,232 ) Net loss applicable to common stockholders $ (15,047 ) $ (17,467 ) Basic and diluted net loss per share $ (0.38 ) $ (0.49 ) Shares used in computing basic and diluted net loss per share 39,414 35,521 Dilutive shares which could exist pursuant to the exercise of outstanding stock instruments and which were not included in the calculation because their affect would have been anti-dilutive are as follows: Year Ended December 31, 2018 (Shares) 2017 (Shares) Warrants to purchase shares of common stock 10,647,026 13,229,778 Options to purchase shares of common stock 2,713,979 5,155,263 Shares of common stock issuable upon conversion preferred stock 4,303,948 4,312,282 17,664,953 22,697,323

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies	10. Commitments and Contingencies Lease Commitments Effective December 31, 2018, the Company entered into an amendment to its operating lease for office space in Norcross, GA for a term of thirty-eight months, beginning on January 1, 2019 and ending February 28, 2022 at a rate of approximately $3,800 per month. The amended lease provided for free rent for the first two months of the lease and continues the security deposit of $6,000. In addition to base rental payments included in the contractual obligations table above, the Company is responsible for our pro-rata share of the operating expenses for the building. Rent expense under this operating lease was $55,000 and $49,000 for the years ended December 31, 2018 and 2017, respectively. Future minimum payments under this lease as of December 31, 2018 are as follows (in thousands): Year ended December 31, 2019 38 2020 46 2021 48 2022 8 Total $ 140 Legal Proceedings The Company records accruals for such contingencies to the extent that the Company concludes that their occurrence is probable and the related damages are estimable. There are no other pending legal proceedings except as noted above.

Galectin Sciences LLC

Galectin Sciences LLC	12 Months Ended
	Dec. 31, 2018
Galectin Sciences LLC	11. Galectin Sciences LLC In January 2014, we created Galectin Sciences, LLC (the “LLC” or “Investee”), a collaborative joint venture co-owned by SBH Sciences, Inc. (“SBH”), to research and develop small organic molecule inhibitors of galectin-3 for oral administration. The LLC was initially capitalized with a $400,000 cash investment to fund future research and development activities, which was provided by the Company, and specific in-process research and development (“IPR&D”) contributed by SBH. The estimated fair value of the IPR&D contributed by SBH, on the date of contribution, was $400,000. Initially, the Company and SBH have a 50% equity ownership interest in the LLC, with neither party having control over the LLC. Accordingly from inception through the fourth quarter of 2014, the Company accounted for its investment in the LLC using the equity method of accounting. Under the equity method of accounting, the Company’s investment was initially recorded at cost with subsequent adjustments to the carrying value to recognize additional investments in or distributions from the Investee, as well as the Company’s share of the Investee’s earnings, losses and/or changes in capital. The estimated fair value of the IPR&D contributed to the LLC was immediately expensed upon contribution as there was no alternative future use available at the point of contribution. The operating agreement provides that if either party does not desire to contribute its equal share of funding required after the initial capitalization, then the other party, providing all of the funding, will have its ownership share increased in proportion to the total amount contributed from inception. In the fourth quarter of 2014, after the LLC had expended the $400,000 in cash, SBH decided not to contribute its share of the funding required. As a result, the Company contributed the $73,000 needed for the fourth quarter of 2014 expenses of the LLC. The Company contributed $164,000, $201,000, $659,000 and $687,000 in 2018, 2017, 2016 and 2015, respectively, and SBH contributed $73,000 and $50,000 in 2017 and 2016, respectively. As of December 31, 2018, the Company’s ownership percentage in the LLC was 80.8%. The Company accounts for the interest in the LLC as a consolidated, less than wholly owned subsidiary. Because the LLC’s equity is immaterial, the value of the non-controlling interest is also deemed to be immaterial. The Company’s portion of the LLC’s net loss for 2014, prior to the change in accounting discussed previously, was $400,000, which includes the Company’s proportionate share of the non-cash charge associated with the contributed IPR&D of $200,000.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Taxes	12. Income Taxes On December 22, 2017, the Tax Cuts and Jobs Act (2017 Tax Act) was enacted. The 2017 Tax Act includes a number of changes to existing U.S. tax laws that impact the Company, most notably a reduction of the U.S. corporate tax rate from 34% to 21%, for tax years beginning after December 31, 2017. The 2017 Tax Act also provides for the implementation of a territorial tax system, a one-time transition tax on certain foreign earnings, the acceleration of depreciation for certain assets placed into service after September 27, 2017 and other prospective changes beginning in 2018, including repeal of the domestic manufacturing deduction, acceleration of tax revenue recognition, capitalization of research and development expenditures, additional limitations on executive compensation and limitations on the deductibility of interest. Pursuant to the SEC Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act, the Company has calculated as final its re-measurement of deferred taxes and has no uncertain tax positions. This includes a provisional amount related to the re-measurement of deferred tax assets based on the rates at which they are expected to reverse in the future, which is generally 21% plus the applicable state tax rate, with a corresponding change to the valuation allowance as of December 31, 2017. No further adjustments were recorded in the year ended December 31, 2018. The components of the net deferred tax assets are as follows at December 31: 2018 2017 (in thousands) Operating loss carryforwards $ 36,417 $ 34,173 Tax credit carryforwards 1,195 1,195 Other temporary differences 4,678 4,064 42,290 39,432 Less valuation allowance (42,290 ) (39,432 ) Net deferred tax asset $ — $ — The primary factors affecting the Company’s income tax rates were as follows: 2018 2017 Tax benefit at U.S. statutory rates (21 %) (34 %) State tax benefit (4.7 %) (3.8 %) Permanent differences 4.0 % 1.7 % Impact of the 2017 Tax Act — 113.1 % Other 1.1 % (4.9 %) Expiring state NOL’s — — Changes in valuation allowance 20.6 % (72.1 %) 0 % 0 % As of December 31, 2018, the Company has federal and state net operating loss carryforwards totaling $8,924,000 $103,172,000 respectively, which expire through 2037. The net operating losses include Federal and State excess benefits related to stock options of $2,121,000 that will be charged to additional paid-in capital when utilized. In addition, the Company has federal and state research and development credits of $1,263,000 and $216,000, respectively, which expire through 2034. Ownership changes, as defined by Section 382 of the Internal Revenue Code, may have limited the amount of net operating loss carryforwards that can be utilized annually to offset future taxable income. Past and subsequent ownership changes could further affect the limitation in future years. Because of the Company’s limited operating history and its recorded losses, management has provided, in each of the last two years, a 100% valuation allowance against the Company’s net deferred tax assets. The Company is subject to taxation in the U.S. and various states. Based on the history of net operating losses all jurisdictions and tax years are open for examination until the operating losses are utilized or the statute of limitations expires. As of December 31, 2018 and 2017, the Company does not have any significant uncertain tax positions.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2018
Subsequent Events	13. Subsequent Events On January 11, 2019, 10X Fund L.P., converted all of its Series B Convertible Preferred Stock into Common Stock of Galectin Therapeutics. Pursuant to the terms of the conversion, as of January 11, 2019, 10X Fund L.P. converted 5,508,000 shares of its Series B-1, B-2 and B-3 Convertible Preferred Stock into 3,789,346 shares of Common Stock of Galectin Therapeutics. All special voting rights and protective provisions that previously benefited the Series B Preferred Stock were extinguished by the conversion to Common Stock. In connection with the conversion of the Series B Preferred Stock, the Company extended by five years the exercise date of warrants for 3,579,642 shares of Common Stock issued by the Company in connection with sale of the Series B-1 and Series B-2 Preferred Stock. Before the extension, the warrants had various expiration dates in 2019 and 2020. The warrant amendments give 10X Fund the right to nominate one director to the Company’s board of directors. Previously, under the now extinguished voting rights of the Series B Preferred, 10X Fund had the right to name two directors and nominate an additional three directors. The Company has accounted for the modified terms of the warrants pursuant to ASC 718, Stock Compensation, whereby the Company has recognized a charge for the change in fair value of the warrants immediately before and immediately after the modification. In January 2019, the Company recognized a one-time non-cash charge of $6,622,000 related to the extension of the 3,579,642 warrants. The following assumptions were used to value the extension of the warrants immediately before and immediately after the modification: a) immediately before the modification — an expected life range of 0.09 to 1.33 years, volatility of 98%, risk free interest rate range of 2.4% to 2.59% and zero dividends and; b) immediately following the modification — an expected life range of 5.09 to 6.33 years, volatility range of 106%, risk free interest rate range of 2.56% to 2.6% and zero dividends.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Basis of Consolidation	Basis of Consolidation. The consolidated financial statements include the accounts of the Company and Galectin Therapeutics Security Corp., its wholly-owned subsidiary, which was incorporated in Delaware on December 23, 2003 and Galectin Sciences LLC (see Note 11). All intercompany transactions have been eliminated.
Use of Estimates	Use of Estimates. The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and judgments that may affect the reported amounts of assets, liabilities, equity, revenue, expenses and related disclosure of contingent assets and liabilities. Management’s estimates and judgments include assumptions used in stock option and warrant liability valuations, useful lives of property and equipment and intangible assets, accrued liabilities, deferred income taxes and various other assumptions that are believed to be reasonable under the circumstances. Actual results may differ from those estimates under different assumptions or conditions.
Fair Value Measurements	Fair Value Measurements . The Company has certain financial assets and liabilities recorded at fair value. Fair values determined by Level 1 inputs utilize observable data such as quoted prices in active markets. Fair values determined by Level 2 inputs utilize data points other than quoted prices in active markets that are observable either directly or indirectly. Fair values determined by Level 3 inputs utilize unobservable data points in which there is little or no market data, which require the reporting entity to develop its own assumptions. The estimated value of accounts payable and accrued expenses approximates their carrying value due to their short-term nature. There were no Level 2 or 3 assets or liabilities at December 31, 2018 or 2017.
Cash and Cash Equivalents	Cash and Cash Equivalents. The Company considers all highly-liquid investments with original maturities of 90 days or less at the time of acquisition to be cash equivalents. The Company had no cash equivalents at December 31, 2018 or 2017.
Prepaid Expenses and Other Current Assets	Prepaid Expenses and Other Current Assets. Prepaid expenses and other assets consist principally of prepaid insurance and deferred financing costs (see Note 8).
Property and Equipment	Property and Equipment. Property and equipment, including leasehold improvements, are stated at cost, net of accumulated depreciation and amortization, and are depreciated or amortized using the straight-line method over the estimated useful lives of the related assets of generally three five
Security Deposit	Security Deposit. At December 31, 2018 and 2017, the Company had a security deposit of $6,000 for leased office space included in Prepaid Expenses and Other Current Assets.
Intangible Assets	Intangible Assets. Intangible assets include patent costs, consisting primarily of related capitalized legal fees, which are amortized over an estimated useful life of five
Long-Lived Assets	Long-Lived Assets. The Company reviews all long-lived assets for impairment whenever events or circumstances indicate the carrying amount of such assets may not be recoverable. Recoverability of assets to be held or used is measured by comparison of the carrying value of the asset to the future undiscounted net cash flows expected to be generated by the asset. If such asset is considered to be impaired, the impairment recognized is measured by the amount by which the carrying value of the asset exceeds the discounted future cash flows expected to be generated by the asset.
Accrued Expenses	Accrued Expenses . As part of the process of preparing our consolidated financial statements, we are required to estimate accrued expenses. This process involves identifying services that third parties have performed on our behalf and estimating the level of service performed and the associated cost incurred on these services as of each balance sheet date in our consolidated financial statements. Examples of estimated accrued expenses include contract service fees in conjunction with clinical trials, professional service fees, such as those arising from the services of attorneys and accountants and accrued payroll expenses. In connection with these service fees, our estimates are most affected by our understanding of the status and timing of services provided relative to the actual services incurred by the service providers. In the event that we do not identify certain costs that have been incurred or we under- or over-estimate the level of services or costs of such services, our reported expenses for a reporting period could be understated or overstated. The date on which certain services commence, the level of services performed on or before a given date, and the cost of services are often subject to our judgment. We make these judgments based upon the facts and circumstances known to us in accordance with accounting principles generally accepted in the U.S.
Warrants	Warrants. The Company has issued common stock warrants in connection with the execution of certain equity and debt financings. The fair value of warrants is determined using the Black-Scholes option-pricing model using assumptions regarding volatility of our common share price, remaining life of the warrant, and risk-free interest rates at each period end. There were no warrant liabilities as of December 31, 2018 or 2017.
Research and Development Expenses	Research and Development Expenses. Costs associated with research and development are expensed as incurred. Research and development expenses include, among other costs, salaries and other personnel-related costs, and costs incurred by outside laboratories and other accredited facilities in connection with clinical trials and preclinical studies.
Income Taxes	Income Taxes. The Company accounts for income taxes in accordance with the accounting rules that requires an asset and liability approach to accounting for income taxes based upon the future expected values of the related assets and liabilities. Deferred income tax assets and liabilities are determined based on the differences between the financial reporting and tax bases of assets and liabilities and for tax loss and credit carry forwards and are measured using the expected tax rates estimated to be in effect when such basis differences reverse. Valuation allowances are established, if necessary, to reduce the deferred tax asset to the amount that will, more likely than not, be realized.
Concentration of Credit Risk	Concentration of Credit Risk. Financial instruments that subject the Company to credit risk consist of cash and cash equivalents and certificates of deposit. The Company maintains cash and cash equivalents and certificates of deposit with well-capitalized financial institutions. At times, those amounts may exceed federally insured limits. The Company has no significant concentrations of credit risk.
Stock-Based Compensation	Stock-Based Compensation. Stock-based compensation cost is measured at the grant date based on the fair value of the award and is recognized as expense over the service period, which generally represents the vesting period. For awards that have performance-based vesting conditions the Company recognizes the expense over the estimated period that the awards are expected to be earned. The Company generally uses the Black-Scholes option-pricing model to calculate the grant date fair value of stock options. For options that only vest upon the achievement of market conditions, the Company values the options using a Monte Carlo model to calculate the grant date fair value of the stock options. The expense related to options that vest based on market conditions is not reversed should those options not ultimately vest. The expense recognized over the service period is required to include an estimate of the awards that will be forfeited. Stock options issued to non-employees are accounted for in accordance with the provisions of ASC Subtopic 505-50, Equity-Based Payments to Non-employees , which requires valuing the stock options using an option pricing model (the Company uses Black-Scholes) and measuring such stock options to their current fair value when they vest.
New Accounting Pronouncements	New Accounting Pronouncements. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) , which requires lessees to recognize the most leases on the balance sheet. The provisions of this guidance are effective for the annual periods beginning after December 15, 2018, and interim periods within those years, with early adoption permitted. The Company is evaluating the requirements of this guidance and has not yet determined the impact of the adoption on our financial position or results of operations.

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2018
Property and Equipment	Property and equipment consist of the following at December 31: 2018 2017 (in thousands) Leasehold improvements $ 2 $ 2 Computer and office equipment 13 13 Furniture and fixtures 59 59 Total 74 74 Less accumulated depreciation and amortization (74 ) (74 ) Property and equipment — net $ — $ —

Accrued Expenses (Tables)

Accrued Expenses (Tables)	12 Months Ended
	Dec. 31, 2018
Accrued Expenses	Accrued expenses consist of the following at December 31: 2018 2017 (in thousands) Legal and accounting fees $ 45 $ 74 Accrued compensation 1,294 790 Accrued research and development costs and other 173 1,428 Total $ 1,512 $ 2,292

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2018
Return on Investment	The ROI Percentage shall mean the percentage that applies as of the redemption date, as follows: ROI Percentage 200% before the second anniversary of the date of issuance; 250% on or after the second anniversary of the date of issuance, but before the third anniversary of the date of issuance; 300% on or after the third anniversary of the date of issuance, but before the fourth anniversary of the date of issuance; 350% on or after the fourth anniversary of the date of issuance, but before the fifth anniversary of the date of issuance; 400% on or after the fifth anniversary of the date of issuance, but before the sixth anniversary of the date of issuance; 450% on or after the sixth anniversary of the date of issuance, but before the seventh anniversary of the date of issuance; 500% on or after the seventh anniversary of the date of issuance, but before the eighth anniversary of the date of issuance; and 550% on or after the eighth anniversary of the date of issuance, but before the ninth anniversary of the date of issuance.

Warrants (Tables)

Warrants (Tables)	12 Months Ended
	Dec. 31, 2018
Summary of Information with Regard to Outstanding Warrants Issued in Connection with Equity and Debt Financings and Consultants	Warrant activity is summarized as follows: Outstanding at December 31, 2016 13,488,296 Issued 1,078,643 Exercised — Canceled (1,337,161 ) Outstanding at December 31, 2017 13,229,778 Issued 290 Exercised (2,583,042 ) Canceled — Outstanding at December 31, 2018 10,647,026 The following table summarizes information with regard to outstanding warrants issued in connection with equity and debt financings and consultants as of December 31, 2018. Issued in Connection With Number Issued Exercise Price Exercisable Date Expiration Date February 12, 2009 Series B-1 Transaction $3.00 Investor Warrants — Class B 1,200,000 $ 3.00 February 12, 2009 February 12, 2019 May 13, 2009 Series B-2 Transaction $3.00 Investor Warrants — Class B 600,000 $ 3.00 May 13, 2009 May 13, 2019 June 30, 2009 Series B-2 Transaction $3.00 Investor Warrants — Class B 333,333 $ 3.00 June 30, 2009 June 30, 2019 August 12, 2009 Series B-2 Transaction $3.00 Investor Warrants — Class B 200,000 $ 3.00 August 12, 2009 August 12, 2019 September 30, 2009 Series B-2 Transaction $3.00 Investor Warrants — Class B 216,666 $ 3.00 September 30, 2009 September 30, 2019 November 4, 2009 Series B-2 Transaction $3.00 Investor Warrants — Class B 106,666 $ 3.00 November 4, 2009 November 4, 2019 December 8, 2009 Series B-2 Transaction $3.00 Investor Warrants — Class B 133,143 $ 3.00 December 8, 2009 December 8, 2019 January 29, 2010 Series B-2 Transaction $3.00 Investor Warrants — Class B 216,667 $ 3.00 January 29, 2010 January 29, 2020 March 8, 2010 Series B-2 Transaction $3.00 Investor Warrants — Class B 223,334 $ 3.00 March 8, 2010 March 8, 2020 April 30, 2010 Series B-2 Transaction $3.00 Investor Warrants — Class B 206,667 $ 3.00 April 30, 2010 April 30, 2020 May 10, 2010 Series B-2 Transaction $3.00 Investor Warrants — Class B 371,667 $ 3.00 May 10, 2010 May 10, 2020 November 25, 2015 Offering Warrants 1,180,240 $ 2.50 May 25, 2016 May 25, 2021 September 22, 2016 Series B-3 Transaction $3.00 Investor Warrants 698,158 $ 3.00 September 22, 2016 September 22, 2023 September 29, 2016 Series B-3 Transaction $3.00 Investor Warrants 846,100 $ 3.00 September 29, 2016 September 29, 2023 December 22, 2016 Private placement warrants 1,466,204 $ 5.00 December 22, 2016 December 23, 2023 December 23, 2016 Series B-3 Transaction $3.00 Investor Warrants 924,780 $ 3.00 December 23, 2016 December 23, 2023 December 28, 2016 Private placement warrants 644,468 $ 5.00 December 28, 2016 December 28, 2023 February 27, 2017 Private placement warrants 76,776 $ 5.00 February 27, 2017 February 27, 2024 2018 and 2017 Warrants issued for services 2,157 $ 5.00 Various dates in 2018 and 2017 Various dates in 2025 and 2024 December 19, 2017 Line of credit warrants 1,000,000 $ 5.00 December 19, 2017 December 19, 2024 Total outstanding warrants 10,647,026

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2018
Stock-Based Compensation Expense Related to Common Stock Options, Restricted Common Stock and Common Stock Warrants	Following is the stock-based compensation expense related to common stock options, restricted common stock and common stock warrants: Year Ended December 31, 2018 2017 Research and development $ 1,944 $ 521 General and administrative 2,501 580 Total stock-based compensation expense $ 4,445 $ 1,101
Weighted Average Assumptions Used to Determine Fair Value of Options Granted	The fair value of the options granted is determined using the Black-Scholes option-pricing model. The following weighted average assumptions were used: 2018 2017 Risk-free interest rate 2.47 % 2.05 % Expected life of the options 5.7 5.5 Expected volatility of the underlying stock 104 % 103 % Expected dividend rate 0 % 0 %
Summary of Stock Option Activity	The following table summarizes the stock option activity in the stock-based compensation plans: Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Life (in years) Aggregate Intrinsic Value (in thousands) Outstanding, December 31, 2016 4,656,888 $ 4.30 Granted 498,375 2.39 Forfeited/Cancelled — — Exercised — — Outstanding, December 31, 2017 5,155,263 $ 4.11 Granted 1,011,875 5.01 Forfeited/Cancelled (1,354,330 ) 7.31 Exercised (2,098,829 ) 2.00 Outstanding, December 31, 2018 2,713,979 $ 4.67 6.74 $ 1,524 Exercisable, December 31, 2018 2,659,114 $ 4.69 6.69 $ 1,518
Summary of Additional Information Regarding Outstanding and Exercisable Options under Stock Based Compensation Plans	The following table summarizes additional information regarding outstanding and exercisable options under our stock-based compensation plans at December 31, 2018: Options Outstanding Options Exercisable Exercise Price (Range) Number of Shares Weighted Average Remaining Contractual Life Weighted Average Exercise Price Number of Shares Weighted Average Exercise Price (in years) $0.87 – 1.00 232,000 7.95 $ 0.88 232,000 $ 0.88 $1.01 – 3.00 854,137 7.35 2.34 851,147 2.34 $3.01 – 5.00 558,392 8.22 3.99 506,517 3.98 $5.01 – 8.00 886,950 5.24 6.55 886,950 6.55 $8.01 – 13.38 182,500 5.06 13.38 182,500 13.38 2,713,979 6.74 $ 4.67 2,659,114 $ 4.68

Loss Per Share (Tables)

Loss Per Share (Tables)	12 Months Ended
	Dec. 31, 2018
Computation of Diluted Net Loss Per Share does not Assume Issuance of Common Shares that have an Anti-dilutive Effect on Net Loss Per Share	The computation of diluted net loss per share does not assume the issuance of common shares that have an anti-dilutive effect on net loss per share. Year Ended December 31, (in thousands, except per share amounts) 2018 2017 Net loss $ (13,900 ) $ (16,235 ) Preferred stock dividends (1,147 ) (1,232 ) Net loss applicable to common stockholders $ (15,047 ) $ (17,467 ) Basic and diluted net loss per share $ (0.38 ) $ (0.49 ) Shares used in computing basic and diluted net loss per share 39,414 35,521
Dilutive Shares Which Could Exist Pursuant to Exercise of Outstanding Stock Instruments and Which were not Included in Calculation	Dilutive shares which could exist pursuant to the exercise of outstanding stock instruments and which were not included in the calculation because their affect would have been anti-dilutive are as follows: Year Ended December 31, 2018 (Shares) 2017 (Shares) Warrants to purchase shares of common stock 10,647,026 13,229,778 Options to purchase shares of common stock 2,713,979 5,155,263 Shares of common stock issuable upon conversion preferred stock 4,303,948 4,312,282 17,664,953 22,697,323

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2018
Future Minimum Payments of Operating Lease	Future minimum payments under this lease as of December 31, 2018 are as follows (in thousands): Year ended December 31, 2019 38 2020 46 2021 48 2022 8 Total $ 140

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Components of Net Deferred Tax Assets	The components of the net deferred tax assets are as follows at December 31: 2018 2017 (in thousands) Operating loss carryforwards $ 36,417 $ 34,173 Tax credit carryforwards 1,195 1,195 Other temporary differences 4,678 4,064 42,290 39,432 Less valuation allowance (42,290 ) (39,432 ) Net deferred tax asset $ — $ —
Primary Factors Affecting Income Tax Rates	The primary factors affecting the Company’s income tax rates were as follows: 2018 2017 Tax benefit at U.S. statutory rates (21 %) (34 %) State tax benefit (4.7 %) (3.8 %) Permanent differences 4.0 % 1.7 % Impact of the 2017 Tax Act — 113.1 % Other 1.1 % (4.9 %) Expiring state NOL’s — — Changes in valuation allowance 20.6 % (72.1 %) 0 % 0 %

Nature of Business and Basis _2

Nature of Business and Basis of Presentation - Additional Information (Detail) - USD ($) $ in Thousands	2 Months Ended	12 Months Ended
	Feb. 28, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Basis of Presentation [Line Items]
Unrestricted cash and cash equivalents		$ 8,253	$ 3,053	$ 15,362
Proceeds from sale of common stock		15,379	$ 3,583
Expected costs of trail and general overhead		$ 100,000
Subsequent Event | 2019 At Market Sales Agreement [Member]
Basis of Presentation [Line Items]
Proceeds from sale of common stock	$ 1,870

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Significant Accounting Policies [Line Items]
Cash equivalents	$ 0	$ 0
Security deposit for leased office space	$ 6,000	6,000
Estimated useful lives of intangible assets	5 years
Amortization expense of intangible assets	$ 0	1,000
Gross intangible assets	78,000	78,000
Accumulated amortization of intangible assets	78,000	78,000
Level 2
Significant Accounting Policies [Line Items]
Fair value of assets	0	0
Fair value of liabilities	0	0
Level 3
Significant Accounting Policies [Line Items]
Fair value of assets	0	0
Fair value of liabilities	$ 0	$ 0
Computer and office equipment
Significant Accounting Policies [Line Items]
Estimated useful lives of property and equipment	3 years
Furniture and fixtures
Significant Accounting Policies [Line Items]
Estimated useful lives of property and equipment	5 years

Property and Equipment (Detail)

Property and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 74	$ 74
Less accumulated depreciation and amortization	(74)	(74)
Property and equipment-net	0	0
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	2	2
Computer and office equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	13	13
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 59	$ 59

Property and Equipment - Additi

Property and Equipment - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense	$ 0	$ 0

Accrued Expenses (Detail)

Accrued Expenses (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Schedule of Accrued Liabilities [Line Items]
Legal and accounting fees	$ 45	$ 74
Accrued compensation	1,294	790
Accrued research and development costs and other	173	1,428
Total	$ 1,512	$ 2,292

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail)

Dec. 23, 2016USD ($)Yearsshares

Sep. 22, 2016USD ($)Yearsshares

Dec. 30, 2010USD ($)$ / sharesshares

Feb. 12, 2009USD ($)shares

Feb. 04, 2008$ / sharesshares

Feb. 28, 2017USD ($)Years$ / sharesshares

Jan. 31, 2014USD ($)shares

Jul. 31, 2011shares

Jan. 31, 2011USD ($)$ / sharesshares

Dec. 31, 2018USD ($)$ / sharesshares

Dec. 31, 2017USD ($)$ / sharesshares

Dec. 31, 2015USD ($)Yearsshares

Dec. 31, 2014shares

Dec. 31, 2013USD ($)shares

Dec. 31, 2011USD ($)$ / sharesshares

Dec. 31, 2010USD ($)Years

Dec. 31, 2009USD ($)Years

Dec. 31, 2008USD ($)

May 31, 2010USD ($)shares

May 19, 2017USD ($)

Mar. 30, 2014USD ($)

Dec. 29, 2010$ / sharesshares

Class of Stock [Line Items]

Common stock, shares authorized

100,000,000

50,000,000

Undesignated stock, shares authorized

20,000,000

20,000,000

Net proceeds from issuance of common stock | $

$ 15,379,000

$ 3,583,000

Warrants issued

500

6,000,000

Exercise price of warrant | $ / shares

$ 7.20

Fair market value of common stock per share | $ / shares

$ 3.43

Common Stock, Value, Issued | $

$ 41,000

$ 36,000

Common Stock, Shares, Issued

41,190,905

35,789,388

Research and development expense | $

$ 6,471,000

$ 11,721,000

Aggregate stated value and proceeds | $

$ 1,008,000

$ 1,500,000

Private Placement 2017

Class of Stock [Line Items]

Shares of common stock issued

102,368

Proceeds from sale of common stock | $

$ 200,000

Warrants issued

76,776

Exercise price of warrant | $ / shares

$ 5

Issuance of warrants, value | $

$ 101,000

Fair market value of common stock per share | $ / shares

$ 1.86

Warrants expiration date

Feb. 28, 2024

Private Placement 2017 | Measurement Input, Price Volatility

Class of Stock [Line Items]

Fair value assumptions, Measurement Input

97

Private Placement 2017 | Measurement Input, Expected Term

Class of Stock [Line Items]

Fair value assumptions, Measurement Input | Years

7

Private Placement 2017 | Measurement Input, Risk Free Interest Rate

Class of Stock [Line Items]

Fair value assumptions, Measurement Input

1.92

Series A Preferred Stock

Class of Stock [Line Items]

Number of warrant to purchase one share of common stock in each unit issued

1

Series B Warrants

Class of Stock [Line Items]

Exercise price of warrant | $ / shares

$ 3

Series A One Warrant

Class of Stock [Line Items]

Number of consecutive trading days

15 days

Market value of common stock | $ / shares

$ 7.50

Cash proceeds from warrant exercises | $

$ 3,000,000

Series A Two Warrant

Class of Stock [Line Items]

Market value of common stock | $ / shares

$ 10.50

Cash proceeds from warrant exercises | $

$ 1,500,000

$ 1,500,000

Number of warrants exercised

500,000

500,000

Additional Paid-In Capital

Class of Stock [Line Items]

Aggregate stated value and proceeds | $

394,000

890,000

Warrant

Class of Stock [Line Items]

Termination notice period

30 days

Number of warrants exercised

2,583,042

1,337,161

Series B-3 8% convertible preferred stock

Class of Stock [Line Items]

Series A 12% convertible preferred stock, shares authorized

2,508,000

2,508,000

Exercise price of warrant | $ / shares

$ 3

Preferred stock, dividend rate

8.00%

Fair value of warrants | $

658,000

2,262,000

Aggregate stated value and proceeds | $

614,000

610,000

Number of common stock issued upon conversion

1,789,346

Embedded beneficial conversion feature | $

$ 310,000

$ 991,000

Series B-3 8% convertible preferred stock | Measurement Input, Price Volatility

Class of Stock [Line Items]

Fair value assumptions, Measurement Input

96

95

Series B-3 8% convertible preferred stock | Measurement Input, Expected Term

Class of Stock [Line Items]

Fair value assumptions, Measurement Input | Years

7

7

Series B-3 8% convertible preferred stock | Measurement Input, Risk Free Interest Rate

Class of Stock [Line Items]

Fair value assumptions, Measurement Input

2.35

1.42

Series B-1 12% convertible preferred stock

Class of Stock [Line Items]

Preferred stock, dividend rate

12.00%

Convertible stock conversion ratio

0.667

Fair value of warrants | $

$ 1,296,000

Preferred stock issuable

3,000,000

Preferred stock value | $

$ 6,000,000

Common shares issuable upon conversion of preferred stock

2,000,000

Convertible stock conversion price | $ / shares

$ 3

Series B-1 12% convertible preferred stock | Measurement Input, Price Volatility

Class of Stock [Line Items]

Fair value assumptions, Measurement Input

118

Series B-1 12% convertible preferred stock | Measurement Input, Expected Term

Class of Stock [Line Items]

Fair value assumptions, Measurement Input | Years

5

Series B-1 12% convertible preferred stock | Measurement Input, Risk Free Interest Rate

Class of Stock [Line Items]

Fair value assumptions, Measurement Input

1.79

Series B-1 12% convertible preferred stock | Additional Paid-In Capital

Class of Stock [Line Items]

Proceeds from issuance of equity | $

$ 1,105,000

Series B-2 12% convertible preferred stock

Class of Stock [Line Items]

Series A 12% convertible preferred stock, shares authorized

2,100,000

2,100,000

Convertible stock conversion ratio

0.667

Fair value of warrants | $

$ 4,148,000

$ 5,333,000

Preferred stock issuable

3,000,000

Preferred stock value | $

$ 6,000,000

Common shares issuable upon conversion of preferred stock

2,000,000

Convertible stock conversion price | $ / shares

$ 3

Liquidation preference per share after series A preferred stock | $ / shares

$ 2

Convertible preferred shares

50,000

Common stocks issued upon conversion of Preferred Stock

8,424

shares relating to prorated dividend prior conversion

90

Series B-2 12% convertible preferred stock | Measurement Input, Expected Term

Class of Stock [Line Items]

Fair value assumptions, Measurement Input | Years

5

5

Series B-2 12% convertible preferred stock | Measurement Input, Expected Dividend Rate

Class of Stock [Line Items]

Fair value assumptions, Measurement Input

0

0

Series B-2 12% convertible preferred stock | Maximum | Measurement Input, Price Volatility

Class of Stock [Line Items]

Fair value assumptions, Measurement Input

129

127

Series B-2 12% convertible preferred stock | Maximum | Measurement Input, Risk Free Interest Rate

Class of Stock [Line Items]

Fair value assumptions, Measurement Input

2.43

2.70

Series B-2 12% convertible preferred stock | Minimum | Measurement Input, Price Volatility

Class of Stock [Line Items]

Fair value assumptions, Measurement Input

126

124

Series B-2 12% convertible preferred stock | Minimum | Measurement Input, Risk Free Interest Rate

Class of Stock [Line Items]

Fair value assumptions, Measurement Input

2.27

1.98

Series B-2 12% convertible preferred stock | Additional Paid-In Capital

Class of Stock [Line Items]

Proceeds from issuance of equity | $

$ 1,028,000

$ 1,732,000

Series B-2 12% convertible preferred stock | Beneficial Conversion Feature

Class of Stock [Line Items]

Proceeds from issuance of equity | $

$ 388,000

$ 628,000

Series C 6% super dividend redeemable convertible preferred stock

Class of Stock [Line Items]

Convertible preferred stock, shares authorized

1,000

1,000

1,000

Shares of common stock issued

212

13

Preferred stock, dividend rate

6.00%

Stock price per share | $ / shares

$ 10,000

$ 10,000

Number of consecutive trading days for conversion of preferred stock

15 days

Stock issuance costs | $

$ 47,000

Common shares issuable upon conversion of preferred stock

1,667

Aggregate stated value and proceeds | $

2,120,000

$ 130,000

Liquidation preference per share after series A preferred stock | $ / shares

$ 10,000

Preferred stock, par value | $ / shares

$ 0.01

Preferred stock, stated value | $ / shares

$ 10,000

Proceeds from issuance of preferred stock, net | $

$ 2,073,000

Convertible preferred shares

5

176

176

20

24

Common stocks issued upon conversion of Preferred Stock

8,334

293,340

293,340

33,756

40,193

Convertible preferred stock dividend | $

Post conversion dividend rights issued

5

20

24

Redemption period

0 days

Post conversion redemption right, return on investment multiplier amount | $

$ 10,000

Preferred stock redemption price | $ / shares

$ 3

Convertible preferred stock, redemption value | $

8,863,000

Series C 6% super dividend redeemable convertible preferred stock | Series A Preferred Stock

Class of Stock [Line Items]

Dividend as percentage of net sales

2.50%

Series C 6% super dividend redeemable convertible preferred stock | Series B One Preferred Stock

Class of Stock [Line Items]

Dividend as percentage of net sales

1.25%

Series C 6% super dividend redeemable convertible preferred stock | Maximum

Class of Stock [Line Items]

Convertible preferred stock dividend | $

$ 100,000

Series C 6% super dividend redeemable convertible preferred stock | Minimum

Class of Stock [Line Items]

Minimum closing price of the common stock to require conversion | $ / shares

$ 18

Series C 6% super dividend redeemable convertible preferred stock | Additional Paid-In Capital

Class of Stock [Line Items]

Convertible preferred stock dividend | $

$ (107,000)

$ (77,000)

Series B-3 8% convertible preferred stock

Class of Stock [Line Items]

Series A 12% convertible preferred stock, shares authorized

2,508,000

Convertible preferred stock, shares authorized

2,508,000

Liquidation preference per share after series A preferred stock | $ / shares

$ 1

Series A 12% convertible preferred stock

Class of Stock [Line Items]

Series A 12% convertible preferred stock, shares authorized

1,742,500

Preferred stock, dividend rate

12.00%

12.00%

Stock price per share | $ / shares

$ 6

Dividend, percentage of value weighted average share price

100.00%

Number of consecutive trading days prior to dividend payment date

20 days

Number of consecutive trading days for conversion of preferred stock

15 days

Subscription advances received | $

$ 1,742,500

Conversion of Series A to common stock

360,000

Convertible preferred stock dividend | $

Series A 12% convertible preferred stock | Scenario 1

Class of Stock [Line Items]

Stock price per share | $ / shares

$ 9

Series A 12% convertible preferred stock | Scenario 2

Class of Stock [Line Items]

Stock price per share | $ / shares

$ 12

Series A 12% convertible preferred stock | First Payment

Class of Stock [Line Items]

Dividend payable date

--03-30

Series A 12% convertible preferred stock | Second Payment

Class of Stock [Line Items]

Dividend payable date

--09-30

Series A 12% convertible preferred stock | Minimum

Class of Stock [Line Items]

Minimum closing price of the common stock to require conversion | $ / shares

$ 18

Series A 12% convertible preferred stock | Additional Paid-In Capital

Class of Stock [Line Items]

Convertible preferred stock dividend | $

$ (146,000)

$ (62,000)

Series B-1 12% convertible preferred stock

Class of Stock [Line Items]

Series A 12% convertible preferred stock, shares authorized

900,000

900,000

Shares of common stock issued

900,000

Warrants issued

1,800,000

Convertible preferred stock dividend | $

$ 55,000

Series B-1 12% convertible preferred stock | Measurement Input, Expected Dividend Rate

Class of Stock [Line Items]

Fair value assumptions, Measurement Input

0

Series B-1 12% convertible preferred stock | Additional Paid-In Capital

Class of Stock [Line Items]

Convertible preferred stock dividend | $

$ (155,000)

$ (257,000)

Series B-2 12% convertible preferred stock

Class of Stock [Line Items]

Series A 12% convertible preferred stock, shares authorized

2,100,000

2,100,000

Shares of common stock issued

2,100,000

Warrants issued

4,200,000

Proceeds from issuance of equity | $

$ 5,483,000

Convertible preferred stock dividend | $

$ 127,000

Series B-2 12% convertible preferred stock | Additional Paid-In Capital

Class of Stock [Line Items]

Convertible preferred stock dividend | $

$ (363,000)

$ (599,000)

Series B redeemable convertible preferred stock

Class of Stock [Line Items]

Dividend, percentage of value weighted average share price

100.00%

Number of consecutive trading days prior to dividend payment date

20 days

Dividends accrue rate

15.00%

Common Stock

Class of Stock [Line Items]

Convertible preferred stock, shares authorized

12,748,500

Conversion of Series A to common stock

60,888

2014 At Market Agreement

Class of Stock [Line Items]

Aggregate offering price | $

$ 30,000,000

Commission to sales agent as a percentage of gross proceeds

3.00%

Shares of common stock issued

1,496,797

Net proceeds from issuance of common stock | $

$ 1,946,000

Other Agreements

Class of Stock [Line Items]

Warrants issued

290

1,867

Exercise price of warrant | $ / shares

$ 5

$ 5

Research and development expense | $

$ 12,000

$ 33,000

Other Agreements | Vendor

Class of Stock [Line Items]

Common Stock, Shares, Issued

2,883

18,667

Other Agreements | Maximum | Vendor

Class of Stock [Line Items]

Common Stock, Value, Issued | $

$ 100,000

B Three Securities Purchase Agreement

Class of Stock [Line Items]

Warrants to purchase common stock issued in agreeing not to sell any share for 18 months

875,000

B Three Securities Purchase Agreement | Maximum

Class of Stock [Line Items]

Warrants to purchase common stock

669,262

B Three Securities Purchase Agreement | Series B-3 8% convertible preferred stock

Class of Stock [Line Items]

Number of shares agreed to issue and sell

1,500,000

Aggregate stated value and proceeds | $

$ 1,500,000

Number of common stock issued upon conversion

892,349

2017 At Market Agreement

Class of Stock [Line Items]

Aggregate offering price | $

$ 30,000,000

Commission to sales agent as a percentage of gross proceeds

3.00%

Shares of common stock issued

669,714

716,563

Net proceeds from issuance of common stock | $

$ 5,603,000

$ 1,437,000

Amended B Three Securities Purchase Agreement | Maximum

Class of Stock [Line Items]

Warrants to purchase common stock

924,780

Amended B Three Securities Purchase Agreement | Series B-3 8% convertible preferred stock

Class of Stock [Line Items]

Number of shares agreed to issue and sell

1,008,000

Aggregate stated value and proceeds | $

$ 1,000,000

Number of common stock issued upon conversion

896,997

Return on Investment (Detail)

Return on Investment (Detail)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2011
Period 1
Class of Stock [Line Items]
ROI Percentage		200.00%
Redemption date	before the second anniversary of the date of issuance;
Period 2
Class of Stock [Line Items]
ROI Percentage		250.00%
Redemption date	on or after the second anniversary of the date of issuance, but before the third anniversary of the date of issuance;
Period 3
Class of Stock [Line Items]
ROI Percentage		300.00%
Redemption date	on or after the third anniversary of the date of issuance, but before the fourth anniversary of the date of issuance;
Period 4
Class of Stock [Line Items]
ROI Percentage		350.00%
Redemption date	on or after the fourth anniversary of the date of issuance, but before the fifth anniversary of the date of issuance;
Period 5
Class of Stock [Line Items]
ROI Percentage		400.00%
Redemption date	on or after the fifth anniversary of the date of issuance, but before the sixth anniversary of the date of issuance;
Period 6
Class of Stock [Line Items]
ROI Percentage		450.00%
Redemption date	on or after the sixth anniversary of the date of issuance, but before the seventh anniversary of the date of issuance;
Period 7
Class of Stock [Line Items]
ROI Percentage		500.00%
Redemption date	on or after the seventh anniversary of the date of issuance, but before the eighth anniversary of the date of issuance; and
Period 8
Class of Stock [Line Items]
ROI Percentage		550.00%
Redemption date	on or after the eighth anniversary of the date of issuance, but before the ninth anniversary of the date of issuance.

Summary of Warrant Activity (De

Summary of Warrant Activity (Detail) - Warrant - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Shares
Beginning Balance	13,229,778	13,488,296
Issued	290	1,078,643
Cancelled	0	0
Exercised	(2,583,042)	(1,337,161)
Ending Balance	10,647,026	13,229,778

Summary of Information with Reg

Summary of Information with Regard to Outstanding Warrants Issued in Connection with Equity and Debt Financing and Consultants (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 30, 2010
Equity [Line Items]
Number Issued	10,647,026
Exercise Price		$ 7.20
February 12, 2009 Series B-1 Transaction
Equity [Line Items]
Number Issued	1,200,000
Exercise Price	$ 3
Exercisable Date	Feb. 12, 2009
Expiration Date	Feb. 12, 2019
May 13, 2009 Series B-2 Transaction
Equity [Line Items]
Number Issued	600,000
Exercise Price	$ 3
Exercisable Date	May 13, 2009
Expiration Date	May 13, 2019
June 30, 2009 Series B-2 Transaction
Equity [Line Items]
Number Issued	333,333
Exercise Price	$ 3
Exercisable Date	Jun. 30, 2009
Expiration Date	Jun. 30, 2019
August 12, 2009 Series B-2 Transaction
Equity [Line Items]
Number Issued	200,000
Exercise Price	$ 3
Exercisable Date	Aug. 12, 2009
Expiration Date	Aug. 12, 2019
September 30, 2009 Series B-2 Transaction
Equity [Line Items]
Number Issued	216,666
Exercise Price	$ 3
Exercisable Date	Sep. 30, 2019
Expiration Date	Sep. 30, 2019
November 4, 2009 Series B-2 Transaction
Equity [Line Items]
Number Issued	106,666
Exercise Price	$ 3
Exercisable Date	Nov. 4, 2009
Expiration Date	Nov. 4, 2019
December 8, 2009 Series B-2 Transaction
Equity [Line Items]
Number Issued	133,143
Exercise Price	$ 3
Exercisable Date	Dec. 8, 2009
Expiration Date	Dec. 8, 2019
January 29, 2010 Series B-2 Transaction
Equity [Line Items]
Number Issued	216,667
Exercise Price	$ 3
Exercisable Date	Jan. 29, 2010
Expiration Date	Jan. 29, 2020
March 8, 2010 Series B-2 Transaction
Equity [Line Items]
Number Issued	223,334
Exercise Price	$ 3
Exercisable Date	Mar. 8, 2010
Expiration Date	Mar. 8, 2020
April 30, 2010 Series B-2 Transaction
Equity [Line Items]
Number Issued	206,667
Exercise Price	$ 3
Exercisable Date	Apr. 30, 2010
Expiration Date	Apr. 30, 2020
May 10, 2010 Series B-2 Transaction
Equity [Line Items]
Number Issued	371,667
Exercise Price	$ 3
Exercisable Date	May 10, 2010
Expiration Date	May 10, 2020
November 25, 2015 Offering Warrants
Equity [Line Items]
Number Issued	1,180,240
Exercise Price	$ 2.50
Exercisable Date	May 25, 2016
Expiration Date	May 25, 2021
September 22, 2016 Series B-3 Transaction
Equity [Line Items]
Number Issued	698,158
Exercise Price	$ 3
Exercisable Date	Sep. 22, 2016
Expiration Date	Sep. 22, 2023
September 29, 2016 Series B-3 Transaction
Equity [Line Items]
Number Issued	846,100
Exercise Price	$ 3
Exercisable Date	Sep. 29, 2016
Expiration Date	Sep. 29, 2023
December 22, 2016 Private Placement Warrants
Equity [Line Items]
Number Issued	1,466,204
Exercise Price	$ 5
Exercisable Date	Dec. 22, 2016
Expiration Date	Dec. 23, 2023
December 23, 2016 Series B-3 Transaction
Equity [Line Items]
Number Issued	924,780
Exercise Price	$ 3
Exercisable Date	Dec. 23, 2016
Expiration Date	Dec. 23, 2023
December 28, 2016 Private Placement Warrants
Equity [Line Items]
Number Issued	644,468
Exercise Price	$ 5
Exercisable Date	Dec. 28, 2016
Expiration Date	Dec. 28, 2023
February 27, 2017 Private Placement Warrants
Equity [Line Items]
Number Issued	76,776
Exercise Price	$ 5
Exercisable Date	Feb. 27, 2017
Expiration Date	Feb. 27, 2024
2018 and 2017 Warrants issued for services
Equity [Line Items]
Exercisable Date	Various dates in 2018 and 2017
Expiration Date	Various dates in 2025 and 2024
Number Issued	2,157
Exercise Price	$ 5
December 19, 2017 Line of Credit Warrants
Equity [Line Items]
Number Issued	1,000,000
Exercise Price	$ 5
Exercisable Date	Dec. 19, 2017
Expiration Date	Dec. 19, 2024

Summary of Information with R_2

Summary of Information with Regard to Outstanding Warrants Issued in Connection with Equity and Debt Financing and Consultants (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2018$ / shares
February 12, 2009 Series B-1 Transaction
Equity [Line Items]
Warrant issuance date	Feb. 12, 2009
Warrant issued price per share	$ 3
May 13, 2009 Series B-2 Transaction
Equity [Line Items]
Warrant issuance date	May 13, 2009
Warrant issued price per share	$ 3
June 30, 2009 Series B-2 Transaction
Equity [Line Items]
Warrant issuance date	Jun. 30, 2009
Warrant issued price per share	$ 3
August 12, 2009 Series B-2 Transaction
Equity [Line Items]
Warrant issuance date	Aug. 12, 2009
Warrant issued price per share	$ 3
September 30, 2009 Series B-2 Transaction
Equity [Line Items]
Warrant issuance date	Sep. 30, 2009
Warrant issued price per share	$ 3
November 4, 2009 Series B-2 Transaction
Equity [Line Items]
Warrant issuance date	Nov. 4, 2009
Warrant issued price per share	$ 3
December 8, 2009 Series B-2 Transaction
Equity [Line Items]
Warrant issuance date	Dec. 8, 2009
Warrant issued price per share	$ 3
January 29, 2010 Series B-2 Transaction
Equity [Line Items]
Warrant issuance date	Jan. 29, 2010
Warrant issued price per share	$ 3
March 8, 2010 Series B-2 Transaction
Equity [Line Items]
Warrant issuance date	Mar. 8, 2010
Warrant issued price per share	$ 3
April 30, 2010 Series B-2 Transaction
Equity [Line Items]
Warrant issuance date	Apr. 30, 2010
Warrant issued price per share	$ 3
May 10, 2010 Series B-2 Transaction
Equity [Line Items]
Warrant issuance date	May 10, 2010
Warrant issued price per share	$ 3
November 25, 2015 Offering Warrants
Equity [Line Items]
Warrant issuance date	Nov. 25, 2015
September 22, 2016 Series B-3 Transaction
Equity [Line Items]
Warrant issuance date	Sep. 22, 2016
Warrant issued price per share	$ 3
September 29, 2016 Series B-3 Transaction
Equity [Line Items]
Warrant issuance date	Sep. 29, 2016
Warrant issued price per share	$ 3
December 22, 2016 Private Placement Warrants
Equity [Line Items]
Warrant issuance date	Dec. 22, 2016
December 23, 2016 Series B-3 Transaction
Equity [Line Items]
Warrant issuance date	Dec. 23, 2016
Warrant issued price per share	$ 3
December 28, 2016 Private Placement Warrants
Equity [Line Items]
Warrant issuance date	Dec. 28, 2016
February 27, 2017 Private Placement Warrants
Equity [Line Items]
Warrant issuance date	Feb. 27, 2017
December 19, 2017 Line of Credit Warrants
Equity [Line Items]
Warrant issuance date	Dec. 19, 2017

Warrants - Additional Informati

Warrants - Additional Information (Detail)	Mar. 28, 2012USD ($)Years$ / sharesshares	Dec. 31, 2017shares	Dec. 31, 2018shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding Warrants			10,647,026
Warrant Fourteen
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Units issued	1,333,361
Shares of common stock issued	2,666,722
Warrants to purchase shares of common stock issued	1,333,361
Warrant issued price per share | $ / shares	$ 5.63
Gross proceeds from issuance of warrants | $	$ 12,000,000
Net cash proceeds from issuance of warrants | $	10,403,000
Value of warrants | $	$ 4,445,000
Outstanding Warrants		1,317,161
Warrants expiration date		Mar. 28, 2017
Warrant Fourteen | Measurement Input, Exercise Price
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value assumptions, warrants	4.20
Warrant Fourteen | Measurement Input, Expected Term
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value assumptions, term of warrants	5 years
Warrant Fourteen | Measurement Input, Price Volatility
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value assumptions, warrants | Years	119
Warrant Fourteen | Measurement Input, Risk Free Interest Rate
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value assumptions, warrants | Years	1.05

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	May 31, 2018	Dec. 31, 2016	May 31, 2014	Feb. 08, 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-plan grants outstanding	2,713,979	5,155,263		4,656,888
Expected life	5 years 8 months 12 days	5 years 6 months
Expected dividend yield used in the option valuation model	0.00%	0.00%
Common stock price	$ 3.43
Weighted-average grant-date fair values of options granted	$ 3.98	$ 1.88
Unvested option	54,865	628,584
Unrecognized compensation cost	$ 83,000
Unrecognized compensation cost, recognition period	4 months 28 days
Number of shares issued upon stock options exercised	2,098,829	0
Options vested	1,409,804	1,142,441
Total fair value of options vested	$ 4,519,000	$ 1,066,000
Non Qualified Options Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-plan stock option grants to employees and non-employees	1,477,379
Non-plan grants outstanding	500,000
Incentive Compensation Plan 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common stock for issuance upon exercise of grants		5,733,334	6,733,334		4,733,334	3,333,334
Stock awards, available for future grant	889,920
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life	5 years
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life	10 years
Restricted Stock | Non Employees Seven Board Of Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock awards granted	37,657
Amortized expense	$ 90,000

Stock-Based Compensation Expens

Stock-Based Compensation Expense Related to Common Stock Options, Restricted Common Stock and Common Stock Warrants (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 4,445	$ 1,101
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	1,944	521
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 2,501	$ 580

Weighted Average Assumptions Us

Weighted Average Assumptions Used to Determine Fair Value of Options Granted (Detail)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	2.47%	2.05%
Expected life of the options	5 years 8 months 12 days	5 years 6 months
Expected volatility of the underlying stock	104.00%	103.00%
Expected dividend rate	0.00%	0.00%

Summary of Stock Option Activit

Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Shares
Beginning Balance	5,155,263	4,656,888
Granted	1,011,875	498,375
Forfeited/Cancelled	(1,354,330)	0
Exercised	(2,098,829)	0
Ending Balance	2,713,979	5,155,263
Exercisable, December 31, 2018	2,659,114
Weighted Average Exercise Price
Beginning Balance	$ 4.11	$ 4.30
Granted	5.01	2.39
Forfeited/Cancelled	7.31	0
Exercised	2	0
Ending Balance	4.67	$ 4.11
Exercisable, December 31, 2018	$ 4.69
Weighted Average Remaining Contractual Life (Years)
Outstanding, December 31, 2018	6 years 8 months 26 days
Exercisable, December 31, 2018	6 years 8 months 8 days
Stock Options Aggregate Intrinsic Value
Outstanding, December 31, 2018	$ 1,524
Exercisable, December 31, 2018	$ 1,518

Summary of Additional Informati

Summary of Additional Information Regarding Outstanding and Exercisable Options under Stock Based Compensation Plans (Detail)	12 Months Ended
	Dec. 31, 2018$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding, Number of Shares | shares	2,713,979
Options Outstanding, Weighted Average Remaining Contractual Life	6 years 8 months 26 days
Options Outstanding, Weighted Average Exercise Price	$ 4.67
Options Exercisable, Number of Shares | shares	2,659,114
Options Exercisable, Weighted Average Exercise Price	$ 4.68
$0.87-$1.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum Exercise Price	0.87
Maximum Exercise Price	$ 1
Options Outstanding, Number of Shares | shares	232,000
Options Outstanding, Weighted Average Remaining Contractual Life	7 years 11 months 12 days
Options Outstanding, Weighted Average Exercise Price	$ 0.88
Options Exercisable, Number of Shares | shares	232,000
Options Exercisable, Weighted Average Exercise Price	$ 0.88
$1.01-$3.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum Exercise Price	1.01
Maximum Exercise Price	$ 3
Options Outstanding, Number of Shares | shares	854,137
Options Outstanding, Weighted Average Remaining Contractual Life	7 years 4 months 6 days
Options Outstanding, Weighted Average Exercise Price	$ 2.34
Options Exercisable, Number of Shares | shares	851,147
Options Exercisable, Weighted Average Exercise Price	$ 2.34
$3.01-$5.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum Exercise Price	3.01
Maximum Exercise Price	$ 5
Options Outstanding, Number of Shares | shares	558,392
Options Outstanding, Weighted Average Remaining Contractual Life	8 years 2 months 19 days
Options Outstanding, Weighted Average Exercise Price	$ 3.99
Options Exercisable, Number of Shares | shares	506,517
Options Exercisable, Weighted Average Exercise Price	$ 3.98
$5.01 - $8.00
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum Exercise Price	5.01
Maximum Exercise Price	$ 8
Options Outstanding, Number of Shares | shares	886,950
Options Outstanding, Weighted Average Remaining Contractual Life	5 years 2 months 26 days
Options Outstanding, Weighted Average Exercise Price	$ 6.55
Options Exercisable, Number of Shares | shares	886,950
Options Exercisable, Weighted Average Exercise Price	$ 6.55
$8.01-$13.38
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum Exercise Price	8.01
Maximum Exercise Price	$ 13.38
Options Outstanding, Number of Shares | shares	182,500
Options Outstanding, Weighted Average Remaining Contractual Life	5 years 22 days
Options Outstanding, Weighted Average Exercise Price	$ 13.38
Options Exercisable, Number of Shares | shares	182,500
Options Exercisable, Weighted Average Exercise Price	$ 13.38

Line of Credit - Additional Inf

Line of Credit - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Jan. 31, 2019	Dec. 19, 2017	Dec. 30, 2010
Line of Credit Facility [Line Items]
Number of securities called by warrant	500,000
Exercise price of warrant					$ 7.20
Warrant value	$ 696,000
Expected life	5 years 8 months 12 days	5 years 6 months
Expected Volatility	104.00%	103.00%
Expected dividend	0.00%	0.00%
Risk free interest rate	2.47%	2.05%
Amortization of interest expense	$ 336,000	$ 12,000
Director And Shareholder [Member]
Line of Credit Facility [Line Items]
Minority interest		7.00%
Unsecured Line Of Credit | Director
Line of Credit Facility [Line Items]
Line of credit facility		$ 10,000,000		$ 10,000,000
Short term borrowing interest rate			2.70%
Number of securities called by warrant	1,000,000	1,000,000
Exercise price of warrant	$ 5	$ 5
Line of credit current	$ 0	$ 0
Warrant
Line of Credit Facility [Line Items]
Expected life	7 years
Expected Volatility	98.00%
Expected dividend	0.00%
Risk free interest rate	2.05%

Computation of Diluted Net Loss

Computation of Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Schedule Of Computation Of Basic And Diluted Earnings Per Common Share [Line Items]
Net loss	$ (13,900)	$ (16,235)
Preferred stock dividends	(1,147)	(1,232)
Net loss applicable to common stockholders	$ (15,047)	$ (17,467)
Basic and diluted net loss per share	$ (0.38)	$ (0.49)
Shares used in computing basic and diluted net loss per share	39,414	35,521

Dilutive Shares Which Could Exi

Dilutive Shares Which Could Exist Pursuant to Exercise of Outstanding Stock Instruments and Which were not Included in Calculation (Detail) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive shares not included in calculation	17,664,953	22,697,323
Warrant
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive shares not included in calculation	10,647,026	13,229,778
Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive shares not included in calculation	2,713,979	5,155,263
Contingently Issuable Shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive shares not included in calculation	4,303,948	4,312,282

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Commitment And Contingencies [Line Items]
Lessee, Operating Lease, Term of Contract	38 months
Rent expense under operating leases	$ 55,000	$ 49,000
Norcross
Commitment And Contingencies [Line Items]
Operating lease agreements, Expiry date	Feb. 28, 2022
Base rent	$ 3,800
Operating lease agreements, Security Deposit	$ 6,000

Future Minimum Payments of Oper

Future Minimum Payments of Operating Lease (Detail) $ in Thousands	Dec. 31, 2018USD ($)
Operating Leased Assets [Line Items]
2,019	$ 38
2,020	46
2,021	48
2,022	8
Total	$ 140

Galectin Science LLC - Addition

Galectin Science LLC - Additional Information (Detail) - Galectin Sciences, LLC - USD ($)	1 Months Ended	3 Months Ended	12 Months Ended
	Jan. 31, 2014	Dec. 31, 2014	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Investments in and Advances to Affiliates [Line Items]
Equity method investment in Galectin Sciences LLC	$ 400,000
Subsequent capital contribution		$ 73,000	$ 164,000	$ 201,000	$ 659,000	$ 687,000
Equity Method Investment, Ownership Percentage	50.00%		80.80%
Loss from equity method investment in Galectin Sciences, LLC							$ (400,000)
Non-cash charge for in-process research and development							$ 200,000
SBH Sciences, Inc
Investments in and Advances to Affiliates [Line Items]
Subsequent capital contribution				$ 73,000	$ 50,000
Ownership Percentage			80.80%
SBH Sciences, Inc | In Process Research and Development
Investments in and Advances to Affiliates [Line Items]
Estimated fair value of the IPR&D Contributed by SBH	$ 400,000

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Taxes [Line Items]
Statutory federal income tax rate	21.00%	34.00%	34.00%
Benefits related to stock options	$ 2,121,000
Deferred tax asset valuation allowance percentage in each of the last two years	100.00%
Scenario, Plan
Income Taxes [Line Items]
Statutory federal income tax rate	21.00%
Internal Revenue Service (IRS)
Income Taxes [Line Items]
Net operating loss carryforwards	$ 136,202,000
Operating loss carryforwards, expiration year	2,037
Research and development credits	$ 1,263,000
Research and development credits, expiration year	2,034
State and Local Jurisdiction
Income Taxes [Line Items]
Net operating loss carryforwards	$ 103,172,000
Operating loss carryforwards, expiration year	2,037
Research and development credits	$ 216,000
Research and development credits, expiration year	2,034
State and Local Jurisdiction | Internal Revenue Service (IRS)
Income Taxes [Line Items]
Net operating loss carryforwards	$ 8,924,000

Components of Net Deferred Tax

Components of Net Deferred Tax Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Components Of Deferred Tax Assets And Liabilities [Line Items]
Operating loss carryforwards	$ 36,417	$ 34,173
Tax credit carryforwards	1,195	1,195
Other temporary differences	4,678	4,064
Deferred Tax Assets, Gross, Total	42,290	39,432
Less valuation allowance	(42,290)	(39,432)
Net deferred tax asset	$ 0	$ 0

Primary Factors Affecting Incom

Primary Factors Affecting Income Tax Rates (Detail)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of Statutory Tax Rate [Line Items]
Tax benefit at U.S. statutory rates	(21.00%)	(34.00%)	(34.00%)
State tax benefit	(4.70%)	(3.80%)
Permanent differences	4.00%	1.70%
Impact of the 2017 Tax Act	0.00%	113.10%
Other	1.10%	(4.90%)
Expiring state NOL's	0.00%	0.00%
Changes in valuation allowance	20.60%	(72.10%)
Effective Income Tax Rate Reconciliation, Percent	0.00%	0.00%

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail)	Jan. 11, 2019shares	Jan. 31, 2019USD ($)shares	Dec. 31, 2018shares
Number of shares called by warrants			500,000
Subsequent Event [Member]
Number of shares called by warrants	3,579,642
Recognition of non cash charge related to extension of warrants | $		$ 6,622,000
Warrants Issued		3,579,642
Subsequent Event [Member] | Minimum Expected Life Range [Member] | Maximum [Member] | Before Modification of Terms of Warrants [Member]
Derivative Liability		1.33
Subsequent Event [Member] | Minimum Expected Life Range [Member] | Maximum [Member] | After Modification of Terms of Warrants [Member]
Derivative Liability		6.33
Subsequent Event [Member] | Minimum Expected Life Range [Member] | Minimum [Member] | Before Modification of Terms of Warrants [Member]
Derivative Liability		0.09
Subsequent Event [Member] | Minimum Expected Life Range [Member] | Minimum [Member] | After Modification of Terms of Warrants [Member]
Derivative Liability		5.09
Subsequent Event [Member] | Measurement Input, Volatility Rate [Member] | Before Modification of Terms of Warrants [Member]
Derivative Liability		98
Subsequent Event [Member] | Measurement Input, Volatility Rate [Member] | After Modification of Terms of Warrants [Member]
Derivative Liability		106
Subsequent Event [Member] | Measurement Input, Risk Free Interest Rate [Member] | Maximum [Member] | Before Modification of Terms of Warrants [Member]
Derivative Liability		2.59
Subsequent Event [Member] | Measurement Input, Risk Free Interest Rate [Member] | Maximum [Member] | After Modification of Terms of Warrants [Member]
Derivative Liability		2.6
Subsequent Event [Member] | Measurement Input, Risk Free Interest Rate [Member] | Minimum [Member] | Before Modification of Terms of Warrants [Member]
Derivative Liability		2.4
Subsequent Event [Member] | Measurement Input, Risk Free Interest Rate [Member] | Minimum [Member] | After Modification of Terms of Warrants [Member]
Derivative Liability		2.56
Subsequent Event [Member] | Measurement Input, Dividend Yield Rate [Member] | Before Modification of Terms of Warrants [Member]
Derivative Liability		0
Subsequent Event [Member] | Measurement Input, Dividend Yield Rate [Member] | After Modification of Terms of Warrants [Member]
Derivative Liability		0
Common Stock [Member] | Subsequent Event [Member] | 10X Fund L.P.[Member]
Common stocks issued upon conversion of Preferred Stock	3,789,346
Series B1 B2 and B3 Convertible Preferred Stock [Member] | Subsequent Event [Member] | 10X Fund L.P.[Member]
Convertible preferred shares	5,508,000