TG Therapeutics (TGTX) 10-K 2 Mar 20 2019 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2019	Feb. 21, 2020	Jun. 30, 2019
Document And Entity Information [Abstract]
Document Type	10-K
Document Annual Report	true
Amendment Flag	false
Document Period End Date	Dec. 31, 2019
Document Transition Report	false
Entity File Number	1-32639
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Registrant Name	TG THERAPEUTICS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	36-3898269
Entity Address, Address Line One	2 Gansevoort St.
Entity Address, Address Line Two	9th Floor
Entity Address, City or Town	New York
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10014
City Area Code	212
Local Phone Number	554-4484
Title of 12(g) Security	Common Stock, par value $0.001
Security Exchange Name	NASDAQ
Entity Central Index Key	0001001316
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		109,401,184
Entity Public Float			$ 687,572,082
Trading Symbol	TGTX

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 112,637	$ 41,958
Short-term investment securities	27,798	26,943
Prepaid research and development	8,105	9,691
Other current assets	611	439
Total current assets	149,151	79,031
Restricted cash	1,251	1,241
Leasehold interest, net	2,129	2,294
Equipment, net	282	251
Right of use asset	9,402	0
Goodwill	799	799
Total assets	163,014	83,616
Current liabilities:
Accounts payable and accrued expenses	30,041	36,377
Other current liabilities	48,994	219
Lease liability - current portion	1,616
Accrued compensation	3,798	2,258
Total current liabilities	84,449	38,854
Deferred rent	0	1,462
Deferred revenue, net of current portion	762	914
Long-term debt	28,970	0
Lease liability - non current	10,218	0
Long-term liabilities	0	18,350
Total liabilities	124,399	59,580
Commitments and contingencies
Stockholders' equity:
Preferred stock, $0.001 par value per share (10,000,000 shares authorized, none issued and outstanding as of December 31, 2019 and 2018)	0	0
Common stock, $0.001 par value per share (150,000,000 shares authorized, 109,425,243 and 83,911,855 shares issued, 109,383,934 and 83,870,546 shares outstanding at December 31, 2019 and 2018, respectively)	109	84
Additional paid-in capital	739,956	552,531
Treasury stock, at cost, 41,309 shares at December 31, 2019 and 2018	(234)	(234)
Accumulated deficit	(701,216)	(528,345)
Total stockholders' equity	38,615	24,036
Total liabilities and stockholders' equity	$ 163,014	$ 83,616

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	150,000,000	150,000,000
Common stock, shares issued	109,425,243	83,911,855
Common stock, shares outstanding	109,383,934	83,870,546
Treasury stock, shares	41,309	41,309

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
License revenue	$ 152	$ 152	$ 152
Research and development:
Non-cash stock expense associated with in licensing agreements	100	4,000	0
Noncash compensation	5,811	5,598	5,647
Other research and development	148,269	149,793	96,886
Total research and development	154,180	159,391	102,533
General and administrative:
Noncash compensation	5,523	7,288	10,298
Other general and administrative	9,504	7,873	6,033
Total general and administrative	15,027	15,161	16,331
Total costs and expenses	169,207	174,552	118,864
Operating loss	(169,055)	(174,400)	(118,712)
Other (income) expense:
Interest expense	5,287	877	845
Other income	(1,471)	(1,795)	(1,081)
Total other (income) expense, net	3,816	(918)	(236)
Net loss	$ (172,871)	$ (173,482)	$ (118,476)
Basic and diluted net loss per common share (in dollars per share)	$ (1.96)	$ (2.30)	$ (1.91)
Weighted average shares used in computing basic and diluted net loss per common share (in shares)	88,368,844	75,466,813	62,069,570

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Accumulated Deficit [Member]	Total
Balance at Dec. 31, 2016	$ 57	$ 272,432	$ (234)	$ (236,387)	$ 35,868
Balance (in shares) at Dec. 31, 2016	56,820,422		41,309
Issuance of common stock in connection with exercise of warrants		2,142			2,142
Issuance of common stock in connection with exercise of warrants (in shares)	887,585
Issuance of restricted stock	$ 2	(2)
Issuance of restricted stock (in shares)	1,836,511
Forfeiture of restricted stock (in shares)	(53,875)
Issuance of common stock (net of offering costs)	$ 6	53,634			53,640
Issuance of common stock (net of offering costs) (in shares)	5,897,436
Issuance of common stock in At-the-Market offerings (net of offering costs)	$ 8	77,865			77,873
Compensation in respect of restricted stock granted to employees, directors and consultants		15,945			15,945
Net loss				(118,476)	(118,476)
Balance at Dec. 31, 2017	$ 73	422,017	$ (234)	(354,863)	66,993
Balance (in shares) at Dec. 31, 2017	73,181,750		41,309
Issuance of common stock in At-the-Market offerings (in shares)	7,793,671
Issuance of restricted stock	$ 2	(2)
Issuance of restricted stock (in shares)	1,562,211
Forfeiture of restricted stock (in shares)	(191,196)
Issuance of common stock (net of offering costs)	$ 9	113,630			113,639
Compensation in respect of restricted stock granted to employees, directors and consultants		12,886			12,886
Shares issued in connection with in-licensing agreements		4,000			4,000
Shares issued in connection with in-licensing agreements (in shares)	333,868
Net loss				(173,482)	(173,482)
Balance at Dec. 31, 2018	$ 84	552,531	$ (234)	(528,345)	24,036
Balance (in shares) at Dec. 31, 2018	83,911,855		41,309
Issuance of common stock in At-the-Market offerings (in shares)	9,025,222
Issuance of restricted stock	$ 1	(1)
Issuance of restricted stock (in shares)	1,851,520
Warrants issued with debt financing		993			993
Forfeiture of restricted stock (in shares)	(116,463)
Issuance of common stock (net of offering costs)	$ 10	77,465			77,475
Issuance of common stock (net of offering costs) (in shares)	10,149,783
Issuance of common stock in At-the-Market offerings (net of offering costs)	$ 14	97,533			97,547
Compensation in respect of restricted stock granted to employees, directors and consultants		11,335			11,335
Shares issued in connection with in-licensing agreements		100			100
Shares issued in connection with in-licensing agreements (in shares)	8,383
Net loss				(172,871)	(172,871)
Balance at Dec. 31, 2019	$ 109	$ 739,956	$ (234)	$ (701,216)	$ 38,615
Balance (in shares) at Dec. 31, 2019	109,425,243		41,309
Issuance of common stock in At-the-Market offerings (in shares)	13,620,165

Consolidated Statements of Eq_2

Consolidated Statements of Equity (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Stockholders' Equity [Abstract]
Offering costs	$ 0.2		$ 3.6
Offering costs, at market	$ 2	$ 2	$ 1.1

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
CASH FLOWS FROM OPERATING ACTIVITIES
Consolidated net loss	$ (172,871)	$ (173,482)	$ (118,476)
Adjustments to reconcile consolidated net loss to net cash used in operating activities:
Non-cash stock compensation expense	11,335	12,886	15,945
Shares issued in connection with in-licensing agreement	100	4,000	0
Depreciation and amortization	100	88	82
Amortization of premium on investment securities			61
Amortization of discount on investment securities	(257)	(119)
Amortization of debt issuance costs	772	0	0
Amortization of leasehold interest	182	135	125
Non-cash change in lease liability and right-of-use asset	2,519	0	0
Change in fair value of notes payable and accrued interest	124	(61)	59
Changes in assets and liabilities:
Decrease (increase) in other current assets	1,395	(1,638)	(2,665)
(Increase) decrease in accrued interest receivable	(11)	14	(25)
Decrease in other assets	0	0	162
(Decrease) increase in accounts payable and accrued expenses	(4,795)	10,957	11,020
Decrease in lease liabilities	(1,548)	0	0
Increase in interest payable	1,491	0	0
Increase in other liabilities	28,810	18,350	0
Increase in deferred rent	0	97	104
Decrease in deferred revenue	(152)	(152)	(152)
Net cash used in operating activities	(132,806)	(128,925)	(93,760)
CASH FLOWS FROM INVESTING ACTIVITIES
Proceeds from maturity of short-term securities	29,250	32,500	19,800
Investment in held-to-maturity securities	(29,837)	(31,230)	(28,006)
Purchases of equipment	(131)	(90)	(2)
Net cash (used in) provided by investing activities	(718)	1,180	(8,208)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from sale of common stock, net	175,021	113,639	131,516
Proceeds from debt financings	29,987	0	0
Proceeds from the exercise of warrants	0	0	2,143
Financing costs paid	(795)	0	0
Net cash provided by financing activities	204,213	113,639	133,659
NET INCREASE (DECREASE) IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	70,689	(14,106)	31,691
CASH, CASH EQUIVALENTS AND RESTRICTED CASH AT BEGINNING OF YEAR	43,199	57,305	25,614
CASH, CASH EQUIVALENTS AND RESTRICTED CASH AT END OF YEAR	$ 113,888	$ 43,199	$ 57,305

Consolidated Statements of Ca_2

Consolidated Statements of Cash Flows - Reconciliation - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation to amounts on consolidated balance sheets:
Cash and cash equivalents	$ 112,637	$ 41,958	$ 56,718
Restricted cash	1,251	1,241	587
Total cash, cash equivalents and restricted cash	113,888	43,199	57,305
NONCASH TRANSACTIONS
Deferred financing costs	988	0	0
Warrants issued with debt financing	993	0	0
Shares issued in connection with in-licensing	100	4,000	0
Reclassification of deferred financing costs to additional paid-in capital	$ 0	$ 0	$ (3)

ORGANIZATION AND SUMMARY OF SIG

ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2019
ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES.
ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	NOTE 1 - ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES DESCRIPTION OF BUSINESS We are a biopharmaceutical company dedicated to developing and delivering medicines for patients with B-cell mediated diseases, including Chronic Lymphocytic Leukemia (CLL), non-Hodgkin Lymphoma (NHL) and Multiple Sclerosis (MS). We have developed a robust B-cell directed research and development (R&D) platform for identification of key B-cell pathways of interest and rapid clinical testing. Currently, we have five B-cell targeted drug candidates in clinical development, with the lead two therapies, ublituximab (TG-1101) and umbralisib (TGR-1202), in pivotal trials for CLL, NHL and MS. Ublituximab is a novel anti-CD20 monoclonal antibody (mAb) that has been glycoengineered for enhanced potency over first generation antibodies. Umbralisib is an oral, once daily, dual inhibitor of PI3K-delta and CK1-epsilon, which may lead to a differentiated safety profile. When used together in combination therapy, ublituximab and umbralisib are referred to as "U2". Additionally, in early clinical development we have an anti-PD-L1 monoclonal antibody referred to as cosibelimab (TG-1501), an oral Bruton’s Tyrosine Kinase (“BTK”) inhibitor referred to as TG-1701, and an anti-CD47/CD19 bispecific antibody referred to as TG-1801. We also actively evaluate complementary products, technologies and companies for in-licensing, partnership, acquisition and/or investment opportunities. To date, we have not received approval for the sale of any of our drug candidates in any market and, therefore, have not generated any product sales from our drug candidates. ​ LIQUIDITY AND CAPITAL RESOURCES We have incurred operating losses since our inception, and expect to continue to incur operating losses for the foreseeable future and may never become profitable. As of December 31, 2019, we have an accumulated deficit of $701.2 million. Our major sources of cash have been proceeds from the private placement and public offering of equity securities, and in 2019 from our loan and security agreement executed with Hercules Capital, Inc. (“Hercules”) (See Note 7 for more information). We have not yet commercialized any of our drug candidates and cannot be sure if we will ever be able to do so. Even if we commercialize one or more of our drug candidates, we may not become profitable. Our ability to achieve profitability depends on many factors, including our ability to obtain regulatory approval for our drug candidates; successfully complete any post-approval regulatory obligations; and successfully commercialize our drug candidates alone or in partnership. We may continue to incur substantial operating losses even if we begin to generate revenues from our drug candidates. As of December 31, 2019, we had $140.4 million in cash and cash equivalents, and investment securities. We anticipate that our cash and cash equivalents, and investment securities as of December 31, 2019 will provide sufficient liquidity for more than a twelve-month period from the date of filing this Annual Report on Form 10-K. The actual amount of cash that we will need to operate is subject to many factors, including, but not limited to, the timing, design and conduct of clinical trials for our drug candidates. We are dependent upon significant future financing to provide the cash necessary to execute our current operations, including the commercialization of any of our drug candidates. Our common stock is quoted on the Nasdaq Capital Market and trades under the symbol “TGTX.” ​ RECENTLY ISSUED ACCOUNTING STANDARDS In July 2018, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update (“ASU”) No. 2018-11, “Leases - Targeted Improvements” (“ASU 2018-11”) as an update to ASU 2016-02, Leases (“ASU 2016-02” or “Topic 842”) issued on February 25, 2016. ASU 2016-02 is effective for public business entities for fiscal years beginning January 1, 2019. ASU 2016-02 required companies to adopt the new leases standard at the beginning of the earliest period presented in the financial statements, which is January 1, 2017, using a modified retrospective transition method where lessees must recognize lease assets and liabilities for all leases even though those leases may have expired before the effective date of January 1, 2017. Lessees must also provide the new and enhanced disclosures for each period presented, including the comparative periods. ASU 2018-11 provides an entity with an additional (and optional) transition method to adopt the new leases standard. Under this new transition method, an entity initially applies the new lease standard at the adoption date and recognizes a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. Consequently, an entity’s reporting for the comparative periods presented in the financial statements in which it adopts the new lease standard will continue to be in accordance with ASC 840, Leases (“ASC 840”). An entity that elects this additional (and optional) transition method must provide the required ASC 840 disclosures for all periods that continue to be in accordance with ASC 840. The amendments do not change the existing disclosure requirements in ASC 840. ASU 2018-11 is effective for public business entities for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years, with earlier adoption permitted. The Company adopted ASU 2018-11 on January 1, 2019 using a modified retrospective method and will not restate comparative periods. We elected the package of practical expedients permitted under the transition guidance, which allows us to carryforward our historical lease classification and our assessment on whether a contract is or contains a lease. The adoption of this guidance resulted in the addition of material balances of right of use assets and lease liabilities to our consolidated balance sheets at January 1, 2019, primarily relating to our lease of office space (see Note 8). The impact to our consolidated statements of operations was not material as a result of this standard. In June 2018, the FASB issued ASU No. 2018-07, “Improvements to Nonemployee Share-Based Payment Accounting” (“ASU 2018-07”). ASU 2018-07 expands the scope of FASB Topic 718, Compensation – Stock Compensation (“Topic 718”) to include share-based payment transactions for acquiring goods and services from nonemployees. An entity should only remeasure equity-classified awards for which a measurement date has not been established through a cumulative-effect adjustment to retained earnings as of the beginning of the fiscal year of adoption. Upon transition, the entity is required to measure these nonemployee awards at fair value as of the adoption date. The entity must not remeasure assets that are completed. Disclosures required at transition include the nature of and reason for the change in accounting principle and, if applicable, quantitative information about the cumulative effect of the change on retained earnings or other components of equity. ASU 2018-07 is effective for public business entities for fiscal years beginning after December 15, 2018, including interim periods within that fiscal year. Early adoption is permitted, but no earlier than an entity’s adoption date of Topic 606. The Company adopted ASU 2018-07 on January 1, 2019. The adoption of ASU 2018-07 did not have a material effect on our consolidated financial statements as of January 1, 2019. The adoption of ASU 2018-07 had no impact on nonemployee performance awards as they are measured based on the outcome that is probable. Other pronouncements issued by the FASB or other authoritative accounting standards with future effective dates are either not applicable or not significant to our condensed consolidated financial statements. USE OF ESTIMATES The preparation of financial statements in conformity with U.S. generally accepted accounting principles (“GAAP”) requires management to make estimates and judgments that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the applicable reporting period. On an ongoing basis, we evaluate our estimates and judgments, including those related to accrued expenses and stock-based compensation. Actual results could differ from those estimates. Such differences could be material to the financial statements. CASH AND CASH EQUIVALENTS We treat liquid investments with original maturities of less than three months when purchased as cash and cash equivalents. RESTRICTED CASH We record cash pledged or held in trust as restricted cash. As of December 31, 2019 and 2018, we have approximately $1.3 million of restricted cash pledged to secure a line of credit as a security deposit for an Office Agreement (see Note 8). INVESTMENT SECURITIES Investment securities at both December 31, 2019 and 2018 consist of short-term government securities. We classify these securities as held-to-maturity. Held-to-maturity securities are those securities in which we have the ability and intent to hold the security until maturity. Held-to-maturity securities are recorded at amortized cost, adjusted for the amortization or accretion of premiums or discounts. Premiums and discounts are amortized or accreted over the life of the related held-to-maturity security as an adjustment to yield using the effective interest method. A decline in the market value of any investment security below cost, that is deemed to be other than temporary, results in a reduction in the carrying amount to fair value. The impairment is charged to operations and a new cost basis for the security is established. Other-than-temporary impairment charges are included in interest and other income (expense), net. Dividend and interest income are recognized when earned. CREDIT RISK Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents and short-term investments. The Company maintains its cash and cash equivalents and short-term investments with high-credit quality financial institutions. At times, such amounts may exceed federally-insured limits. REVENUE RECOGNITION Effective January 1, 2018, the Company began recognizing revenue under ASC Topic 606, Revenue from Contracts with Customers ● Step 1: Identify the contract with the customer ● Step 2: Identify the performance obligations in the contract ● Step 3: Determine the transaction price ● Step 4: Allocate the transaction price to the performance obligations in the contract ● Step 5: Recognize revenue when the company satisfies a performance obligation In order to identify the performance obligations in a contract with a customer, a company must assess the promised goods or services in the contract and identify each promised good or service that is distinct. A performance obligation meets ASC 606’s definition of a “distinct” good or service (or bundle of goods or services) if both of the following criteria are met: ● The customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer (i.e., the good or service is capable of being distinct). ● The entity’s promise to transfer the good or service to the customer is separately identifiable from other promises in the contract (i.e., the promise to transfer the good or service is distinct within the context of the contract). If a good or service is not distinct, the good or service is combined with other promised goods or services until a bundle of goods or services is identified that is distinct. The transaction price is the amount of consideration to which an entity expects to be entitled in exchange for transferring promised goods or services to a customer, excluding amounts collected on behalf of third parties (for example, some sales taxes). The consideration promised in a contract with a customer may include fixed amounts, variable amounts, or both. Variable consideration is included in the transaction price only to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. The transaction price is allocated to each performance obligation on a relative standalone selling price basis. The transaction price allocated to each performance obligation is recognized when that performance obligation is satisfied, at a point in time or over time as appropriate. RESEARCH AND DEVELOPMENT COSTS Generally, research and development costs are expensed as incurred. Nonrefundable advance payments for goods or services that will be used or rendered for future research and development activities are deferred and amortized over the period that the goods are delivered or the related services are performed, subject to an assessment of recoverability. We make estimates of costs incurred in relation to external clinical research organizations, or CROs, and clinical site costs. We analyze the progress of clinical trials, including levels of patient enrollment, invoices received and contracted costs when evaluating the adequacy of the amount expensed and the related prepaid asset and accrued liability. Significant judgments and estimates must be made and used in determining the accrued balance and expense in any accounting period. We review and accrue CRO expenses and clinical trial study expenses based on work performed and rely upon estimates of those costs applicable to the stage of completion of a study. Accrued CRO costs are subject to revisions as such trials progress to completion. Revisions are charged to expense in the period in which the facts that give rise to the revision become known. With respect to clinical site costs, the financial terms of these agreements are subject to negotiation and vary from contract to contract. Payments under these contracts may be uneven, and depend on factors such as the achievement of certain events, the successful recruitment of patients, the completion of portions of the clinical trial or similar conditions. The objective of our policy is to match the recording of expenses in our financial statements to the actual services received and efforts expended. As such, expense accruals related to clinical site costs are recognized based on our estimate of the degree of completion of the event or events specified in the specific clinical study or trial contract. Prepaid research and development in our consolidated balance sheets includes, among other things, costs related to agreements with CRO’s, certain costs to third party service providers related to development and manufacturing services as well as clinical development. These agreements often require payments in advance of services performed or goods received. Accordingly, as of December 31, 2019 and December 31, 2018, we recorded approximately $8.1 million and $9.7 million, respectively, in prepaid research and development related to such advance agreements. INCOME TAXES Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to temporary differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases, operating losses and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in operations in the period that includes the enactment date. If the likelihood of realizing the deferred tax assets or liability is less than “more likely than not,” a valuation allowance is then created. We, and our subsidiaries, file income tax returns in the U.S. Federal jurisdiction and in various states. We have tax net operating loss carryforwards that are subject to examination for a number of years beyond the year in which they were generated for tax purposes. Since a portion of these net operating loss carryforwards may be utilized in the future, many of these net operating loss carryforwards will remain subject to examination. We recognize interest and penalties related to uncertain income tax positions in income tax expense. Refer to Note 9 for further information on impact of tax reform. STOCK-BASED COMPENSATION We recognize all stock-based payments to employees and non-employee directors (as compensation for service) as noncash compensation expense in the consolidated financial statements based on the fair values of such payments. Stock-based compensation expense recognized each period is based on the value of the portion of stock-based payment awards that is ultimately expected to vest during the period. Forfeitures are recognized as they occur. In addition, because some of the options, restricted stock and warrants issued to employees, consultants and other third parties vest upon achievement of certain milestones, the total expense is uncertain. Compensation expense for such awards that vest upon the achievement of milestones is recognized when the achievement of such milestones becomes probable. BASIC AND DILUTED NET LOSS PER COMMON SHARE Basic net loss per share of our common stock is calculated by dividing net loss applicable to the common stock by the weighted-average number of our common stock outstanding for the period. Diluted net loss per share of common stock is the same as basic net loss per share of common stock since potentially dilutive securities from stock options, stock warrants and convertible preferred stock would have an antidilutive effect either because we incurred a net loss during the period presented or because such potentially dilutive securities were out of the money and the Company realized net income during the period presented. The amounts of potentially dilutive securities excluded from the calculation were 8,361,739, 6,528,932 and 4,835,706 at December 31, 2019, 2018 and 2017, respectively. During the years ended December 31, 2019, 2018 and 2017, the Company incurred a net loss, therefore, all of the securities are antidilutive and excluded from the computation of diluted loss per share. ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2019 2018 2017 Unvested restricted stock 5,591,786 4,595,689 4,820,143 Options 2,605,730 1,916,900 — Shares issuable upon note conversion 17,165 16,343 15,563 Warrants 147,058 — — Total 8,361,739 6,528,932 4,835,706 ​ LONG-LIVED ASSETS AND GOODWILL Long-lived assets are reviewed for potential impairment when circumstances indicate that the carrying value of long-lived tangible and intangible assets with finite lives may not be recoverable. Management’s policy in determining whether an impairment indicator exists, a triggering event, comprises measurable operating performance criteria as well as qualitative measures. If an analysis is necessitated by the occurrence of a triggering event, we make certain assumptions in determining the impairment amount. If the carrying amount of an asset exceeds its estimated future cash flows, an impairment charge is recognized. Goodwill is reviewed for impairment annually, or earlier when events arise that could indicate that an impairment exists. We test for goodwill impairment using a two-step process. The first step compares the fair value of the reporting unit with the unit’s carrying value, including goodwill. When the carrying value of the reporting unit is greater than fair value, the unit’s goodwill may be impaired, and the second step must be completed to measure the amount of the goodwill impairment charge, if any. In the second step, the implied fair value of the reporting unit’s goodwill is compared with the carrying amount of the unit’s goodwill. If the carrying amount is greater than the implied fair value, the carrying value of the goodwill must be written down to its implied fair value. We will continue to perform impairment tests annually, at December 31, and whenever events or changes in circumstances suggest that the carrying value of an asset may not be recoverable. There was no impairment to goodwill as of December 31, 2019.

CASH AND CASH EQUIVALENTS

CASH AND CASH EQUIVALENTS	12 Months Ended
	Dec. 31, 2019
CASH. AND CASH EQUIVALENTS.
CASH AND CASH EQUIVALENTS	NOTE 2 – CASH AND CASH EQUIVALENTS The following tables summarize our cash and cash equivalents at December 31, 2019 and 2018: ​ ​ ​ ​ ​ ​ ​ ​ December 31, December 31, (in thousands) ​ 2019 ​ 2018 ​ ​ ​ ​ ​ Checking and bank deposits $ 110,135 $ 39,268 Money market funds ​ ​ 2,502 ​ ​ 2,690 Total ​ $ 112,637 ​ $ 41,958 ​

INVESTMENT SECURITIES

INVESTMENT SECURITIES	12 Months Ended
	Dec. 31, 2019
INVESTMENT SECURITIES
INVESTMENT SECURITIES	NOTE 3 – INVESTMENT SECURITIES Our investments as of December 31, 2019 and 2018 are classified as held-to-maturity. Held-to-maturity investments are recorded at amortized cost. The following tables summarize our investment securities at December 31, 2019 and 2018: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ Amortized ​ Gross ​ Gross ​ ​ ​ ​ ​ cost, as ​ unrealized ​ unrealized ​ Estimated (in thousands) adjusted holding gains holding losses fair value Short-term investments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Obligations of domestic governmental agencies (maturing between January 2020 and September 2020) (held-to-maturity) ​ $ 27,798 ​ $ 28 ​ $ — ​ $ 27,826 Total short-term investment securities ​ $ 27,798 ​ $ 28 ​ $ — ​ $ 27,826 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2018 ​ Amortized Gross Gross ​ ​ ​ ​ cost, as ​ unrealized ​ unrealized ​ Estimated ​ ​ adjusted ​ holding gains ​ holding losses ​ fair value Short-term investments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Obligations of domestic governmental agencies (maturing between January 2019 and November 2019) (held-to-maturity) ​ $ 26,943 ​ $ 2 ​ $ 10 ​ $ 26,935 Total short-term investment securities ​ $ 26,943 ​ $ 2 ​ $ 10 ​ $ 26,935 ​

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	12 Months Ended
	Dec. 31, 2019
FAIR VALUE MEASUREMENTS
FAIR VALUE MEASUREMENTS	NOTE 4 – FAIR VALUE MEASUREMENTS We measure certain financial assets and liabilities at fair value on a recurring basis in the financial statements. The fair value hierarchy ranks the quality and reliability of inputs, or assumptions, used in the determination of fair value and requires financial assets and liabilities carried at fair value to be classified and disclosed in one of the following three categories: ● Level 1 – quoted prices in active markets for identical assets and liabilities; ● Level 2 – inputs other than Level 1 quoted prices that are directly or indirectly observable; and ● Level 3 – unobservable inputs that are not corroborated by market data. As of December 31, 2019 and 2018, the fair values of cash and cash equivalents, restricted cash, and notes and interest payable approximate their carrying value. At the time of our merger (we were then known as Manhattan Pharmaceuticals, Inc. (“Manhattan”) with Ariston Pharmaceuticals, Inc. (“Ariston”) in March 2010, Ariston issued $15.5 million of five-year 5% notes payable (the “5% Notes”) in satisfaction of several note payable issuances. The 5% Notes and accrued and unpaid interest thereon are convertible at the option of the holder into common stock at the conversion price of $1,125 per share. Ariston agreed to make quarterly payments on the 5% Notes equal to 50% of the net product cash flow received from the exploitation or commercialization of Ariston’s product candidates, AST-726 and AST-915. We have no obligations under the 5% Notes aside from a) 50% of the net product cash flows from Ariston’s product candidates, if any, payable to noteholders; and b) the conversion feature, discussed above. The cumulative liability including accrued and unpaid interest of the 5% Notes was approximately $19.3 million at December 31, 2019 and $18.4 million at December 31, 2018. No payments have been made on the 5% Notes through December 31, 2019. In December 2011, we elected the fair value option for valuing the 5% Notes. The fair value option was elected in order to reflect in our financial statements the assumptions that market participants use in evaluating these financial instruments. As of December 31, 2013, as a result of expiring intellectual property rights and other factors, it was determined that net product cash flows from AST-726 were unlikely. As we have no other obligations under the 5% Notes aside from the net product cash flows and the conversion feature, the conversion feature was used to estimate the 5% Notes’ fair value as of December 31, 2019 and 2018. The assumptions, assessments and projections of future revenues are subject to uncertainties, difficult to predict, and require significant judgment. The use of different assumptions, applying different judgment to inherently subjective matters and changes in future market conditions could result in significantly different estimates of fair value and the differences could be material to our consolidated financial statements. The following tables provide the fair value measurements of applicable financial liabilities as of December 31, 2019 and 2018: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Financial liabilities at fair value as of December 31, 2019 (in thousands) Level 1 Level 2 Level 3 Total ​ ​ ​ ​ ​ ​ ​ ​ ​ 5% Notes ​ $ — ​ $ — ​ $ 190 ​ $ 190 Total ​ $ — ​ $ — ​ $ 190 ​ $ 190 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Financial liabilities at fair value as of December 31, 2018 ​ Level 1 Level 2 Level 3 Total ​ ​ ​ ​ ​ 5% Notes ​ $ — ​ $ — ​ $ 67 ​ $ 67 Total ​ $ — ​ $ — ​ $ 67 ​ $ 67 ​ The Level 3 amounts above represent the fair value of the 5% Notes and related accrued interest. The following table summarizes the changes in Level 3 instruments for the years ended December 31, 2018 and 2019: ​ ​ ​ ​ (in thousands) ​ ​ ​ Balance at January 1, 2018 $ 128 Interest accrued on face value of 5% Notes ​ 878 Conversion of 5% Notes ​ — Change in fair value of Level 3 liabilities ​ (939) Balance at December 31, 2018 ​ 67 Interest accrued on face value of 5% Notes ​ 924 Conversion of 5% Notes ​ — Change in fair value of Level 3 liabilities ​ (801) Balance at December 31, 2019 ​ $ 190 ​ The change in the fair value of the Level 3 liabilities is reported in other (income) expense in the accompanying consolidated statements of operations.

STOCKHOLDERS' EQUITY

STOCKHOLDERS' EQUITY	12 Months Ended
	Dec. 31, 2019
STOCKHOLDERS' EQUITY
STOCKHOLDERS' EQUITY	NOTE 5 – STOCKHOLDERS’ EQUITY Preferred Stock Our amended and restated certificate of incorporation authorizes the issuance of up to 10,000,000 shares of preferred stock, $0.001 par value, with rights senior to those of our common stock, issuable in one or more series. Upon issuance, the Company can determine the rights, preferences, privileges and restrictions thereof. These rights, preferences and privileges could include dividend rights, conversion rights, voting rights, terms of redemption, liquidation preferences, sinking fund terms and the number of shares constituting any series or the designation of such series, any or all of which may be greater than the rights of common stock. Stockholder Rights Plan On July 18, 2014, we adopted a stockholder rights plan. The stockholder rights plan is embodied in the Stockholder Protection Rights Agreement dated as of July 18, 2014 (the "Rights Agreement"), between us and American Stock Transfer & Trust Company, LLC, as rights agent (the "Rights Agent"). Accordingly, the Board of Directors declared a distribution of one right (a “Right”) for each outstanding share of common stock, to stockholders of record at the close of business on July 28, 2014, for each share of common stock issued (including shares distributed from treasury) by us thereafter and prior to the Separation Time (as defined in the Rights Agreement), and for certain shares of common stock issued after the Separation Time. Following the Separation Time, each Right entitles the registered holder to purchase from us one one-thousandth one-thousandth The Rights Agreement was approved by our Board of Directors on July 18, 2014. The Rights will expire at the close of business on its ten year Common Stock Our amended and restated certificate of incorporation authorizes the issuance of up to 150,000,000 shares of $0.001 par value common stock. In December 2014, we filed a shelf registration statement on Form S-3 (the "2015 S-3"), which was declared effective in January 2015. Under the 2015 S-3, the Company may sell up to a total of $250 million of its securities. In connection with the 2015 S-3, we amended our 2013 At-the-Market Issuance Sales Agreement with MLV & Co, LLC (“MLV”) (the "2015 ATM") such that we may issue and sell additional shares of our common stock, having an aggregate offering price of up to $175.0 million, from time to time through MLV and FBR Capital Markets & Co. ("FBR", each of MLV and FBR individually an "Agent" and collectively the "Agents"), acting as the sales agents. Under the 2015 ATM we pay the Agents a commission rate of up to 3.0% of the gross proceeds from the sale of any shares of common stock sold through the Agents. During the year ended December 31, 2017, we sold a total of 3,104,253 shares of common stock under the 2015 ATM for aggregate total gross proceeds of approximately $31.6 million at an average selling price of $10.18 per share, resulting in net proceeds of approximately $31.0 million after deducting commissions and other transaction costs. In March 2017, we completed an underwritten public offering of 5,128,206 shares of our common stock (plus a 30-day In May 2017, we filed a shelf registration statement on Form S-3 (the "2017 S-3"), which was declared effective in June 2017, replacing the 2015 S-3. Under the 2017 S-3, we may sell up to a total of $300 million of securities. In connection with the 2017 S-3, we entered into an At-the-Market Issuance Sales Agreement (the "2017 ATM") with Jefferies LLC, Cantor Fitzgerald & Co., FBR Capital Markets & Co., SunTrust Robinson Humphrey, Inc., Raymond James & Associates, Inc., Ladenburg Thalmann & Co. Inc. and H.C. Wainwright & Co., LLC (each an "Agent" and collectively, the "Agents"), relating to the sale of shares of our common stock. Under the 2017 ATM we pay the 2017 Agents a commission rate of up to 3.0% of the gross proceeds from the sale of any shares of common stock. During the year ended December 31, 2018, we sold a total of 9,025,222 shares of common stock under the 2017 ATM for aggregate total gross proceeds of approximately $115.8 million at an average selling price of $12.83 per share, resulting in net proceeds of approximately $113.7 million after deducting commissions and other transactions costs. During the year ended December 31, 2019, we sold a total of 13,620,165 shares of common stock under the 2017 ATM for aggregate total gross proceeds of approximately $99.3 million at an average selling price of $7.29 per share, resulting in net proceeds of approximately $97.5 million after deducting commissions and other transactions costs. ​ On March 1, 2019, we completed a public offering of 4,100,000 shares of our common stock (plus a 30-day On September 5, 2019, we filed an automatic "shelf registration" statement on Form S-3 (the "2019 WKSI") as a "well-known seasoned issuer" as defined in Rule 405 under the Securities Act of 1933, as amended. The 2019 WKSI was declared effective in September 2019. Under this shelf process, we may sell any combination of the securities described in the related prospectus in one or more offerings. On December 22, 2019, we completed a securities purchase agreement with an institutional investor in which we agreed to sell 5,434,783 shares of our common stock at a price of $9.20. Net proceeds from this offering were approximately $50.0 million. The 2017 S-3 and the 2019 WKSI are currently our only active shelf registration statements. After deducting shares already sold, there is approximately $9.5 million of common stock that remains available for sale under the 2017 S-3, and unlimited capacity under the 2019 WKSI, at December 31, 2019. We may offer the securities under the 2017 S-3 and 2019 WKSI from time to time in response to market conditions or other circumstances if we believe such a plan of financing is in the best interests of our stockholders. We believe that the 2019 WKSI provides us with the flexibility to raise additional capital to finance our operations as needed. Treasury Stock As of December 31, 2019 and 2018, 41,309 shares of common stock are being held in Treasury, at a cost of approximately $234,000, representing the fair market value on the date the shares were surrendered to the Company to satisfy employee tax obligations. Equity Incentive Plans The TG Therapeutics, Inc. Amended and Restated 2012 Incentive Plan (“2012 Incentive Plan”) was approved by stockholders in June 2018. Pursuant to this amendment, 6,000,000 shares were added to the 2012 Incentive Plan. As of December 31, 2019 and 2018, 2,605,730 and 1,916,900 options, respectively, were outstanding and up to an additional 779,346 shares may be issued under the 2012 Incentive Plan. Effective as of January 1, 2017, we entered into an amendment (the “Amendment”) to the employment agreement entered into as of December 15, 2011 (together with the Amendment, the “Employment Agreement”) with Michael S. Weiss, our Executive Chairman and Chief Executive Officer and President. Under the Amendment, Mr. Weiss will remain as Chief Executive Officer and President, removing the interim status. Simultaneously, we entered into a Strategic Advisory Agreement (the “Advisory Agreement”) with Caribe BioAdvisors, LLC (the “Advisor”) owned by Mr. Weiss to provide the services of Mr. Weiss as Chairman of the Board and as Executive Chairman. As part of the Amendment, Mr. Weiss also agreed to forfeit 3,381,866 restricted shares previously granted under the Employment Agreement that were predominantly subject to time-based vesting over the next three years. Simultaneously, (i) Mr. Weiss was issued 418,371 restricted shares under the Employment Agreement that vest in 2018 and 2019 and (ii) the Advisor was issued 2,960,000 restricted shares under the Advisory Agreement that vested on market capitalization thresholds ranging from $375 million to $750 million. In accordance with GAAP, there was no incremental stock compensation expense recognition as a result of the modification. Stock Options The estimated fair value of the options granted in the year ended December 31, 2019 was determined utilizing the Black-Scholes option-pricing model at the date of grant. The following table summarizes stock option activity for the years ended December 31, 2019 and 2018: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ ​ ​ ​ ​ ​ ​ average ​ ​ ​ ​ ​ ​ ​ Weighted- ​ Contractual ​ ​ ​ ​ ​ Number of ​ average ​ Term ​ Aggregate ​ ​ shares ​ exercise price ​ (in years) ​ intrinsic value ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Outstanding at December 31, 2017 — ​ ​ — ​ — ​ $ — Granted 1,916,900 ​ $ 6.50 ​ ​ ​ Exercised — ​ — ​ ​ ​ Forfeited — ​ — ​ ​ ​ Expired — ​ ​ — ​ ​ ​ Outstanding at December 31, 2018 ​ 1,916,900 ​ $ 6.50 ​ 9.75 ​ $ — Granted ​ 815,000 ​ ​ 7.18 ​ ​ ​ ​ ​ Exercised ​ — ​ ​ — ​ ​ ​ ​ ​ Forfeited ​ (126,170) ​ ​ 6.10 ​ ​ ​ ​ ​ Expired ​ — ​ ​ — ​ ​ ​ ​ ​ Outstanding at December 31, 2019 ​ 2,605,730 ​ $ 6.73 ​ 8.92 ​ $ 11,706,110 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Vested and expected to vest at December 31, 2019 2,605,730 ​ $ 6.73 8.92 ​ $ 11,706,110 ​ Total expense associated with the stock options was approximately $3.5 million, zero and zero during the years ended December 31, 2019, 2018 and 2017, respectively. As of December 31, 2019, there was approximately $2.6 million of total unrecognized compensation cost related to unvested time-based stock options, which is expected to be recognized over a weighted-average period of 1.5 years. As of December 31, 2019, the stock options outstanding include options granted to both employees and non-employees which are both time-based and milestone-based. Stock-based compensation for milestone-based options will be recorded if and when a milestone occurs. We recognized stock compensation expense of $0.3 million during the year ended December 31, 2019 for these stock options. The fair value of the Company’s option awards were estimated using the assumptions below: ​ ​ ​ ​ ​ ​ ​ ​ Year ended ​ ​ ​ December 31, ​ December 31, ​ ​ 2019 ​ 2018 Volatility 172.99-291.61 192.76-296.71 ​ Expected term (in years) 5.0-6.25 5.0-6.25 ​ Risk-free rate 1.82-2.49 % 2.49-2.56 % Expected dividend yield -- ​ -- ​ ​ Restricted Stock Certain employees, directors and consultants have been awarded restricted stock. The restricted stock vesting consists of milestone and time-based vesting. The following table summarizes restricted share activity for the years ended December 31, 2019, 2018 and 2017: ​ ​ ​ ​ ​ ​ ​ ​ Weighted Average ​ ​ ​ ​ Grant Date Fair ​ ​ Number of Shares ​ Value Outstanding at January 1, 2017 8,642,055 $ 7.20 Granted 1,836,511 ​ 6.40 Vested (4,103,048) ​ 5.24 Forfeited (53,875) ​ 8.47 Outstanding at December 31, 2017 6,321,643 ​ 7.17 Granted 1,562,211 ​ 13.07 Vested (1,596,966) ​ 9.38 Forfeited (191,196) ​ 8.13 Outstanding at December 31, 2018 6,095,692 ​ ​ 8.07 Granted 1,851,520 ​ 12.95 Vested (738,960) ​ 9.08 Forfeited (116,463) ​ 7.96 Outstanding at December 31, 2019 7,091,789 ​ $ 7.78 ​ ​ ​ ​ ​ ​ ​ Total compensation expense associated with restricted stock grants was $7.8 million, $12.9 million and $15.9 million during the years ended December 31, 2019, 2018 and 2017, respectively. As of December 31, 2019, there was approximately $15.3 million of total unrecognized compensation expense related to unvested time-based restricted stock, which is expected to be recognized over a weighted-average period of 1 year Warrants The following table summarizes warrant activity for the years ended December 31, 2019, 2018 and 2017: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ ​ ​ ​ average exercise ​ Aggregate ​ ​ Warrants ​ price ​ intrinsic value Outstanding at January 1, 2017 913,379 ​ $ 2.41 ​ $ 1,961,403 Issued — ​ — ​ ​ Exercised (887,585) ​ 2.41 ​ ​ Expired (25,794) ​ — ​ ​ Outstanding at December 31, 2017 — ​ — ​ ​ — Issued — ​ — ​ ​ Exercised — ​ — ​ ​ Expired — ​ — ​ ​ Outstanding at December 31, 2018 — ​ ​ — ​ ​ — Issued 147,058 ​ 4.08 ​ ​ Exercised — ​ — ​ ​ Expired — ​ — ​ ​ Outstanding at December 31, 2019 147,058 ​ $ 4.08 ​ $ 1,032,347 ​ There was no expense related to warrants during the years ended December 31, 2019, 2018 and 2017.

OTHER LIABILITIES

OTHER LIABILITIES	12 Months Ended
	Dec. 31, 2019
OTHER LIABILITIES
OTHER LIABILITIES	NOTE 6 – OTHER LIABILITIES The following is a summary of notes payable included in other current liabilities on the Company's consolidated balance sheet: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (in thousands) ​ December 31, 2019 ​ December 31, 2018 ​ ​ ​ ​ Non- ​ ​ ​ ​ ​ ​ Non- ​ ​ ​ ​ ​ Current ​ current ​ ​ ​ ​ Current ​ current ​ ​ ​ ​ ​ portion, ​ portion, ​ ​ ​ ​ portion, ​ portion, ​ ​ ​ ​ net net Total net net Total Convertible 5% Notes Payable ​ $ 190 ​ $ — ​ $ 190 ​ $ 67 ​ $ — ​ $ 67 Totals ​ $ 190 ​ $ — ​ $ 190 ​ $ 67 ​ $ — ​ $ 67 ​ Convertible 5% Notes Payable The 5% Notes and accrued and unpaid interest thereon are convertible at the option of the holder into common stock at the conversion price of $1,125 per share. We have no obligation under the 5% Notes aside from (a) 50% of the net product cash flows from Ariston’s product candidates, if any, payable to noteholders; and (b) the conversion feature, discussed above. Interest accrues monthly, is added to principal on an annual basis, every March 8, and is payable at maturity, which was March 8, 2015 (see Note 4 for further details). The cumulative liability including accrued and unpaid interest of these notes was approximately $19.3 million at December 31, 2019 and $18.4 million at December 31, 2018. No payments have been made on the 5% Notes through December 31, 2019. In December 2011, we elected the fair value option for valuing the 5% Notes. The fair value option was elected in order to reflect in our financial statements the assumptions that market participants use in evaluating these financial instruments (see Note 4 for further details). Current Liabilities In 2018, we entered into an agreement with a contract manufacturer for the clinical and potential commercial supply of one of our product candidates. As part of this agreement, the contract manufacturer has agreed to defer payment of certain costs and expenses under the agreement in exchange for the payment of an administrative fee. To date we have incurred expenses related to this agreement of approximately $47.2 million as of December 31, 2019, which include service fees, raw material costs and administrative fees. No payments have been made to the contract manufacturer as of December 31, 2019. Accordingly, as of December 31, 2019, $47.2 million is included in current liabilities in the Company’s consolidated balance sheet, of which $19.6 million is due in the first quarter of 2020. As of December 31, 2018, $18.4 million is included in long-term liabilities in the Company’s condensed consolidated balance sheet. We will incur an administrative fee of six percent (6%) per year starting from the date of invoice issuance. For the year ended December 31, 2019, we have accrued $1.2 million in administrative fees in connection with these costs, which has been included in interest expense in the Company’s consolidated statements of operations.

LONG-TERM DEBT

LONG-TERM DEBT	12 Months Ended
	Dec. 31, 2019
LONG-TERM DEBT.
LONG-TERM DEBT	NOTE 7 - LONG-TERM DEBT On February 28, 2019 (the “Closing Date”), we entered into a term loan facility of up to $60.0 million (“Term Loan”) with Hercules, the proceeds of which were used for research and development programs and for general corporate purposes. The Term Loan is governed by a loan and security agreement, dated February 28, 2019 (the “Loan Agreement”), which provides for up to four separate advances. The first advance of $30.0 million was drawn on the Closing Date. Two additional advances of $10.0 million may be drawn at our option but subject to certain clinical trial milestones, and the fourth advance of $10.0 million, available in minimum increments of $5.0 million, is available through December 15, 2020 subject to the approval of Hercules’ investment committee. The Term Loan will mature on March 1, 2022 (the “Loan Maturity Date”). Each advance accrues interest at a per annum rate of interest equal to the greater of either (i) the “prime rate” as reported in The Wall Street Journal plus 4.75%, and (ii) 10.25%. The Term Loan provides for interest-only payments until October 1, 2020. The interest-only period may be extended to April 1, 2021 if, on or before September 30, 2020, we achieve either the third milestone or we have raised at least $150.0 million in unrestricted net cash proceeds from one or more equity financings, subordinated indebtedness and/or upfront proceeds from business development transactions permitted under the Loan Agreement, in each case after February 7, 2019, and prior to September 30, 2020 (“Milestone IV”). Thereafter, amortization payments will be payable monthly in eighteen installments (or, if the period requiring interest-only payments has been extended to April 1, 2021, in twelve installments) of principal and interest (subject to recalculation upon a change in prime rates). As a result of the Company having raised in excess of $150 million before the required timeline in the Loan Agreement, the interest-only period has been extended to April 1, 2021. At our option upon seven business days’ prior written notice to Hercules, we may prepay all or any portion greater than or equal to $5.0 million of the outstanding advances by paying the entire principal balance (or portion thereof), all accrued and unpaid interest, subject to a prepayment charge of 3.0%, if such advance is prepaid in any of the first twelve months following the Closing Date; 1.5%, if such advance is prepaid after twelve months following the Closing Date but on or prior to twenty-four months following the Closing Date; and 0% thereafter. In addition, a final payment equal to 3.5% of the aggregate principal amount of the loan extended by Hercules is due on the maturity date. Amounts outstanding during an event of default shall be payable on demand and accrue interest at an additional rate of 4.0% per annum of the past due amount outstanding. The Term Loan is secured by a lien on substantially all of our assets, other than intellectual property and contains customary covenants and representations, including a liquidity covenant, financial reporting covenant and limitations on dividends, indebtedness, collateral, investments, distributions, transfers, mergers or acquisitions, taxes, corporate changes, deposit accounts, and subsidiaries. As of and through December 31, 2019, the Company has been in compliance with all covenants. The events of default under the Loan Agreement include, without limitation, and subject to customary grace periods, (1) our failure to make any payments of principal or interest under the Loan Agreement, promissory notes or other loan documents, (2) our breach or default in the performance of any covenant under the Loan Agreement, (3) the occurrence of a material adverse effect, (4) a false or misleading representation or warranty in any material respect, (5) our insolvency or bankruptcy, (6) certain attachments or judgments on the Borrower’s assets, or (7) the occurrence of any material default under certain agreements or obligations involving indebtedness in excess of $750,000. If an event of default occurs, Hercules is entitled to take enforcement action, including acceleration of amounts due under the Loan Agreement. The Loan Agreement also contains warrant coverage of 2% of the total amount funded. A warrant (the “Hercules Warrant”) was issued to Hercules to purchase 147,058 shares of common stock with an exercise price of $4.08. The Hercules Warrant is exercisable for seven years from the date of issuance. Hercules may exercise the Hercules Warrant either by (a) cash or check or (b) through a net issuance conversion. The shares will be registered and freely tradeable within six months of issuance. We accounted for the Hercules Warrant as an equity instrument since it was indexed to our common shares and met the criteria for classification in shareholders equity. The relative fair value of the Hercules Warrant on the date of issuance was approximately $1.0 million and was treated as debt issuance costs and as an offset to the Term Loan. This amount will be amortized to interest expense using the straight-line method, which approximates the effective interest method, over the life of the Term Loan. The Company estimated the fair value of the Hercules Warrant using the Black-Scholes model based on the following key assumptions: ​ ​ ​ ​ ​ Exercise Price $ 4.08 Common share price on date of issuance ​ $ 6.80 ​ Volatility ​ 195.9 % Risk-free interest rate ​ 2.63 % Expected dividend yield ​ -- % Contractual term (in years) ​ 7.00 years ​ ​ The Company incurred financing expenses of $2.8 million (including the fair value of the Hercules Warrant) related to the Hercules Loan Agreement which are recorded as debt issuance costs and as an offset to long-term debt on the Company’s consolidated balance sheet. The debt issuance costs are being amortized over the term of the debt using the straight-line method, which approximates the effective interest method, and are included in interest expense in the Company’s consolidated statements of operations. Amortization of debt issuance costs was $0.8 million for the year ended December 31, 2019. At December 31, 2019, the remaining unamortized balance of debt issuance costs was $2.0 million. Long-term debt as of December 31, 2019, is as follows (in thousands): ​ ​ ​ ​ ​ December 31, ​ 2019 Long-term debt ​ $ 30,000 End of term fee ​ 975 ​ ​ 30,975 Less: unamortized debt issuance costs ​ (2,005) ​ ​ 28,970 Less: Current portion ​ — Long-term debt non-current ​ $ 28,970 ​

LEASES

LEASES	12 Months Ended
	Dec. 31, 2019
LEASES
LEASES	NOTE 8 - LEASES In October 2014, we entered into an agreement (the “Office Agreement”) with Fortress Biotech, Inc. (“FBIO”) to occupy approximately 45% of the 24,000 square feet of New York City office space leased by FBIO. The Office Agreement requires us to pay our respective share of the average annual rent and other costs of the 15-year The initial commitment period of the 45% rate was for a period of three (3) years. We and FBIO currently determine actual office space utilization annually and if our utilization differs from the amount we have been billed, we will either receive credits or be assessed incremental utilization charges. As of December 31, 2019, the allocation rate is 61% and will be evaluated again in August 2020 for the following rent year. Also in connection with this lease, in October 2014 we pledged $0.6 million to secure a line of credit as a security deposit for the Office Agreement, which has been recorded as restricted cash in the accompanying consolidated balance sheets. Additional collateral of $0.6 million was pledged in April 2018 to increase the letter of credit for the office space. In October 2019, we finalized a five-year lease for office space in New Jersey (the “NJ Lease”). We approximate an average annual rental obligation of $0.3 million under the NJ Lease. We took possession of this space in October 2019, with rental payments beginning in November 2019. The following components of lease expense are included in the Company’s consolidated statements of operations for the year ended December 31, 2019 and 2018: ​ ​ ​ ​ ​ ​ ​ ​ December 31, December 31, (in thousands) 2019 2018 Operating lease cost ​ $ 2,651 ​ $ 1,440 Net lease cost ​ $ 2,651 ​ $ 1,440 ​ As of December 31, 2019, the weighted-average remaining operating lease term was 8.4 years and the weighted-average discount rate for operating leases was 10.25%. Cash paid for amounts included in the measurement of operating lease liabilities during the year ended December 31, 2019 was $1.5 million. The balance sheet classification of lease liabilities was as follows: ​ ​ ​ ​ ​ December 31, (in thousands) 2019 Liabilities ​ Lease liability current portion ​ $ 1,616 Lease liability non-current ​ 10,218 Total lease liability ​ $ 11,834 ​ As of December 31, 2019, the maturities of lease liabilities were as follows: ​ ​ ​ ​ ​ Operating (in thousands) ​ leases 2020 ​ $ 1,804 2021 ​ 1,874 2022 ​ 1,911 2023 ​ 1,913 2024 ​ 1,796 After 2024 ​ 10,615 Total lease payments ​ 19,913 Less: Interest ​ (8,079) Present value of lease liabilities(*) ​ $ 11,834 ​ (*) As our leases do not provide an implicit rate, we use our incremental borrowing rate based on the information available at commencement date and considering the term of the lease to determine the present value of lease payments. We used the incremental borrowing rate of 10.25% on February 28, 2019, for operating leases that commenced prior to that date.

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2019
INCOME. TAXES.
INCOME TAXES	NOTE 9 – INCOME TAXES We account for income taxes under the asset and liability method. Deferred tax assets and liabilities are determined based on differences between the financial reporting and tax basis of assets and liabilities and are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse. A valuation allowance is established when necessary to reduce deferred tax assets to the amount expected to be realized. In determining the need for a valuation allowance, management reviews both positive and negative evidence, including current and historical results of operations, future income projections and the overall prospects of our business. Based upon management’s assessment of all available evidence, we believe that it is more-likely-than-not that the deferred tax assets will not be realizable, and therefore, a valuation allowance has been established. The valuation allowance for deferred tax assets was approximately $186,711,000 and $142,947,000 as of December 31, 2019 and 2018, respectively. On December 22, 2017, H.R.1, commonly known as the Tax Cuts and Jobs Act (the “Act”) was signed into law. Among other things, the Act reduced our corporate federal tax rate from 34% to 21% effective January 1, 2018. As a result, we were required to re-measure, through income tax expense, our deferred tax assets and liabilities using the enacted rate at which we expect them to be recovered or settled. The re-measurement of our net deferred tax asset would have resulted in additional income tax expense of $51,767,584 as of December 31, 2017; however, with full valuation allowance in place, the expense was reversed through a corresponding adjustment to the valuation allowance, resulting in no impact on income tax expense. As of December 31, 2019, we have U.S. net operating loss carryforwards (“NOLs”) of approximately $709,949,000, research and development credit carryforwards (“R&D credits”) of approximately $22,483,000 and business interest expense carryforward of $3,189,000. For income tax purposes, these NOLs and R&D credits will expire in various amounts through 2037. NOLs generated after 2017 and the business interest expense carryforwards do not expire. The Tax Reform Act of 1986 contains provisions which limit the ability to utilize net operating loss carryforwards and R&D credit carryforwards in the case of certain events including significant changes in ownership interests. The Exchange Transaction with TG Bio may have resulted in a “change in ownership” as defined by IRC Section 382 of the Internal Revenue Code of 1986, as amended. Additionally, stock issuance activities may have resulted in a “change in ownership” as defined by IRC Section 382 of the Internal Revenue Code of 1986, as amended. Accordingly, a substantial portion of the Company’s NOLs above may be subject to annual limitations in reducing any future year’s taxable income, and a substantial portion of the R&D Credit carryforwards may be subject to annual limitations in reducing any future year’s tax. The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities at December 31, 2019 and 2018 are presented below. ​ ​ ​ ​ ​ ​ ​ (in thousands) 2019 2018 Deferred tax assets: ​ ​ Net operating loss carryforwards ​ $ 158,177 ​ $ 122,678 Research and development credit ​ 22,483 ​ 15,217 Noncash compensation ​ 4,680 ​ 4,394 Disallowed interest ​ ​ 710 ​ ​ — Other ​ 661 ​ 658 Deferred tax asset, excluding valuation allowance ​ 186,711 ​ 142,947 ​ ​ ​ ​ ​ ​ ​ Less valuation allowance ​ (186,711) ​ (142,947) Net deferred tax assets ​ $ — ​ $ — ​ There was no current or deferred ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, (in thousands) 2019 2018 2017 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loss before income taxes, as reported in the consolidated statements of operations ​ $ (172,871) ​ $ (173,482) ​ $ (118,476) ​ ​ ​ ​ ​ Computed “expected” tax benefit ​ $ (36,303) ​ $ (36,431) ​ ​ (40,282) ​ ​ ​ ​ ​ Increase (decrease) in income taxes resulting from: ​ ​ ​ ​ Expected benefit from state and local taxes ​ (2,128) ​ (2,243) ​ (1,106) Research and development credits ​ (7,266) ​ (4,726) ​ (3,697) Other ​ 641 ​ 639 ​ 1,563 Stock options ​ 1,292 ​ (473) ​ 8,213 Enactment of federal tax reform ​ — ​ — ​ 51,768 Change in the balance of the valuation allowance for deferred tax assets ​ 43,764 ​ 43,234 ​ (16,459) ​ ​ $ — ​ $ — ​ $ — ​ We file income tax returns in the U.S Federal and various state and local jurisdictions. With certain exceptions, the Company is no longer subject to U.S. Federal and state income tax examinations by tax authorities for years prior to 2016. However, NOLs and tax credits generated from those prior years could still be adjusted upon audit. The Company would recognize interest and penalties, if any, to uncertain tax position in income tax expense in the statement of operations. There was no accrual for interest and penalties related to uncertain tax positions for 2019. We do not believe that there will be a material change in our unrecognized tax positions over the next twelve months. All of the unrecognized tax benefits, if recognized, would be offset by the valuation allowance.

LICENSE AGREEMENTS

LICENSE AGREEMENTS	12 Months Ended
	Dec. 31, 2019
LICENSE AGREEMENTS
LICENSE AGREEMENTS	NOTE 10 – LICENSE AGREEMENTS TG-1101 (Ublituximab) In November 2012, we entered into an exclusive (within the territory) sublicense agreement with Ildong Pharmaceutical Co. Ltd. (“Ildong”) relating to the development and commercialization of ublituximab in South Korea and Southeast Asia. Under the terms of the sublicense agreement, Ildong has been granted a royalty bearing, exclusive right, including the right to grant sublicenses, to develop and commercialize ublituximab in South Korea, Taiwan, Singapore, Indonesia, Malaysia, Thailand, Philippines, Vietnam, and Myanmar. An upfront payment of $2.0 million, which was received in December 2012, net of $0.3 million of income tax withholdings, is being recognized as license revenue on a straight-line basis over the life of the agreement, which is through the expiration of the last licensed patent right or 15 years after the first commercial sale of a product in such country, unless the agreement is earlier terminated, and represents the estimated period over which we will have certain ongoing responsibilities under the sublicense agreement. We recorded license revenue of approximately $152,000 for each of the years ended December 31, 2019 and 2018, and, at December 31, 2019 and 2018, have deferred revenue of approximately $0.9 million and $1.1 million, respectively, associated with this $2 million payment (approximately $152,000 of which has been classified in current liabilities at December 31, 2019 and 2018). We may receive up to an additional $5.0 million in payments upon the achievement of pre-specified milestones. In addition, upon commercialization, Ildong will make royalty payments to us on net sales of ublituximab in the sublicense territory. TGR-1202 (Umbralisib) On September 22, 2014, we exercised our option to license the global rights to umbralisib, thereby entering into an exclusive licensing agreement (the “TGR-1202 License”) with Rhizen Pharmaceuticals, SA (“Rhizen”) for the development and commercialization of umbralisib. Prior to this, we had been jointly developing umbralisib in a 50:50 joint venture with Rhizen. Under the terms of the TGR-1202 License, Rhizen received a $4.0 million cash payment and 371,530 shares of our common stock as an upfront license fee. With respect to umbralisib, Rhizen will be eligible to receive regulatory filing, approval and sales-based milestone payments in the aggregate of approximately $175 million, a small portion of which will be payable on the first New Drug Application (NDA) filing and the remainder on approval in multiple jurisdictions for up to two oncology indications and one non-oncology indication and attaining certain sales milestones. In addition, if umbralisib is co-formulated with another drug to create a new product (a "New Product"), Rhizen will be eligible to receive similar regulatory approval and sales-based milestone payments for such New Product. Additionally, Rhizen will be entitled to tiered royalties on our future net sales of umbralisib and any New Product. In lieu of sales milestones and royalties on net sales, Rhizen shall also be eligible to participate in sublicensing revenue, if any, based on a percentage that decreases as a function of the number of patients treated in clinical trials following the exercise of the license option. Rhizen will retain global manufacturing rights to umbralisib, provided that they are price competitive with alternative manufacturers. TG-1501: PDL1 (Cosibelimab) ​ In March 2015, we entered into a Global Collaboration Agreement (“Collaboration Agreement”) with Checkpoint for the development and commercialization of anti-PD-L1 and anti-GITR antibody research programs in the field of hematological malignancies. The Collaboration Agreement was amended in June 2019 and upon execution of the amendment we incurred an upfront fee of $1.0 million. We incurred expenses of approximately $4.1 million and $0.6 million for the years ended December 31, 2019 and 2018, the majority of which relates to manufacturing expenses of PD-L1. The relevant expenses are recorded in other research and development in the accompanying consolidated statement of operations. ​ TG-1601: BET In May 2016, as part of a broader agreement with Jubilant Biosys (“Jubilant”), we entered into a sub-license agreement (“JBET Agreement”) with Checkpoint Therapeutics, Inc. (“Checkpoint”) (see Note 11), for the development and commercialization of Jubilant’s novel BET inhibitor program in the field of hematological malignancies. Under the terms of the agreement, we paid Checkpoint an up-front licensing fee of $1.0 million and will make additional payments contingent on certain preclinical, clinical, and regulatory milestones, including commercial milestones totaling up to approximately $177 million and a single-digit royalty on net sales. TG will also provide funding to support certain targeted research efforts at Jubilant. TG-1701: BTK In January 2018, we entered into a global exclusive license agreement with Jiangsu Hengrui Medicine Co. (“Hengrui”), to acquire worldwide intellectual property rights, excluding Asia but including Japan, and for the research, development, manufacturing, and commercialization of products containing or comprising of any of Hengrui’s Bruton’s Tyrosine Kinase inhibitors containing the compounds of either TG-1701 (SHR1459 or EBI1459) or TG1702 (SHR1266 or EBI1266). Pursuant to the agreement, in April 2018, we paid Jiangsu an upfront fee of $1.0 million in our common stock recorded to noncash stock expense associated with in-licensing agreements in our condensed consolidated statement of operations. In addition, in July 2019, we paid Jiangsu the first milestone of $0.1 million in our common stock recorded to noncash stock expense associated with in-licensing agreements in our consolidated statement of operations. Jiangsu is eligible to receive milestone payments totaling approximately $350 million upon and subject to the achievement of certain milestones. Various provisions allow for payments in conjunction with the agreement to be made in cash or our common stock, while others limit the form of payment. Royalty payments in the low double digits are due on net sales of licensed products and revenue from sublicenses. TG-1801: anti-CD47/anti-CD19 In June 2018, we entered into a Joint Venture and License Option Agreement with Novimmune SA (“Novimmune”) to collaborate on the development and commercialization of Novimmune’s novel first-in-class anti-CD47/anti-CD19 bispecific antibody known as TG-1801 (previously NI-1701). The companies will jointly develop the product on a worldwide basis, focusing on indications in the area of hematologic B-cell malignancies. We serve as the primary responsible party for the development, manufacturing and commercialization of the product. Pursuant to the agreement, in June 2018 we paid Novimmune an upfront payment of $3.0 million in our common stock recorded to noncash stock expense associated with in-licensing agreements in our consolidated statement of operations. Further milestone payments will be paid based on early clinical development, and the Company will be responsible for the costs of clinical development of the product through the end of the Phase 2 clinical trials, after which the Company and Novimmune will be jointly responsible for all development and commercialization costs. The Company and Novimmune will each maintain an exclusive option, exercisable at specific times during development, for the Company to license the rights to TG-1801, in which case Novimmune is eligible to receive additional milestone payments totaling approximately $185 million as well as tiered royalties on net sales in the high single to low double digits upon and subject to the achievement of certain milestones.

RELATED PARTY TRANSACTIONS

RELATED PARTY TRANSACTIONS	12 Months Ended
	Dec. 31, 2019
RELATED PARTY TRANSACTIONS
RELATED PARTY TRANSACTIONS	NOTE 11 – RELATED PARTY TRANSACTIONS Other Parties In October 2014, we entered into the Office Agreement with FBIO, to occupy approximately 45% of the 24,000 square feet of New York City office space leased by FBIO. The Office Agreement requires us to pay our respective share of the average annual rent and other costs of the 15-year Under the Office Agreement, we agreed to pay FBIO our portion of the build out costs, which have been allocated to us at the 45% rate mentioned above. The allocated build-out costs have been recorded in Leasehold Interest, net on the Company's condensed consolidated balance sheets and will be amortized over the 15-year 3 In July 2015, we entered into a Shared Services Agreement (the “Shared Services Agreement”) with FBIO to share the cost of certain services such as facilities use, personnel costs and other overhead and administrative costs. This Shared Services Agreement requires us to pay our respective share of services utilized. In connection with the Shared Services Agreement, we incurred expenses of approximately $0.9 million, $1.6 million and $1.2 million for shared services for the years ended December 31, 2019, 2018 and 2017, primarily related to shared personnel. In May 2016, as part of a broader agreement with Jubilant, we entered into a sublicense agreement with Checkpoint, a subsidiary of FBIO, for the development and commercialization of Jubilant’s novel BET inhibitor program in the field of hematological malignancies. We paid Checkpoint an up-front licensing fee of $1.0 million in July 2016 and incurred expenses of $0.2 million in March 2017 for the first milestone achievement as part of the JBET Agreement which is recorded in other research and development in the accompanying consolidated statement of operations. In March 2015, we entered into a Global Collaboration Agreement (“Collaboration Agreement”) with Checkpoint for the development and commercialization of anti-PD-L1 and anti-GITR antibody research programs in the field of hematological malignancies. The Collaboration Agreement was amended in June 2019 and upon execution of the amendment we incurred an upfront fee of $1.0 million. We incurred expenses of approximately $4.1 million and $0.6 million for the years ended December 31, 2019 and 2018 , the majority of which relates to manufacturing expenses of PD-L1. The relevant expenses are recorded in other research and development in the accompanying consolidated statement of operations.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2019
COMMITMENTS AND CONTINGENCIES
COMMITMENTS AND CONTINGENCIES	NOTE 12 – COMMITMENTS AND CONTINGENCIES As of December 31, 2019, we have known contractual obligations; commitments and contingencies of $97.6 million related to our long term liabilities and operating lease obligations. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Less than 1 ​ ​ ​ ​ ​ ​ ​ More than Payment due by period (in thousands) Total year 1-3 years 3-5 years 5 years Contractual obligations ​ ​ ​ ​ ​ Operating leases ​ $ 20,440 ​ $ 2,331 ​ $ 3,785 ​ $ 3,709 ​ $ 10,615 Long-term debt ​ ​ 30,000 ​ ​ — ​ ​ 30,000 ​ ​ — ​ ​ — Contract manufacturer ​ 47,168 ​ 47,168 ​ — ​ — ​ — Total ​ $ 97,608 ​ $ 49,499 ​ $ 33,785 ​ $ 3,709 ​ $ 10,615 ​ Contract Manufacturer See Note 6 for a detailed description of our current liabilities. Future minimum contractual commitments as of December 31, 2019 total approximately $47.2 million and are due in 2020. Leases See Note 8 for a detailed description of our lease arrangements in New York and New Jersey. Total rental expense was approximately $2.7 million, $1.4 million and $1.4 million for the years ended December 31, 2019, 2018, and 2017, respectively. Future minimum lease commitments as of December 31, 2019, in the aggregate total approximately $20.4 million through December 31, 2031. The preceding table shows future minimum lease commitments, which include our office leases in New York, New Jersey, North Carolina and Tennessee by year as of December 31, 2019. ​

QUARTERLY FINANCIAL INFORMATION

QUARTERLY FINANCIAL INFORMATION	12 Months Ended
	Dec. 31, 2019
QUARTERLY FINANCIAL INFORMATION
QUARTERLY FINANCIAL INFORMATION	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ NOTE 13 – QUARTERLY FINANCIAL INFORMATION (UNAUDITED) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 3 Months Ended ​ ​ March 31, ​ June 30, ​ September 30, ​ December 31, (in thousands) 2019 2019 2019 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ License revenue ​ $ 38 ​ $ 38 ​ $ 38 ​ $ 38 ​ ​ ​ ​ ​ Total costs and expenses ​ 34,727 ​ 35,582 ​ 60,899 ​ 37,998 ​ ​ ​ ​ ​ Net loss ​ $ (35,156) ​ $ (36,213) ​ $ (61,930) ​ $ (39,571) ​ ​ ​ ​ ​ ​ Basic and diluted net loss per common share ​ $ (0.43) ​ $ (0.42) ​ $ (0.69) ​ $ (0.44) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 3 Months Ended ​ March 31, June 30, September 30, December 31, (in thousands) ​ 2018 ​ 2018 ​ 2018 ​ 2018 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ License revenue ​ $ 38 ​ $ 38 ​ $ 38 ​ $ 38 ​ ​ ​ ​ ​ Total costs and expenses ​ 41,615 ​ 44,383 ​ 34,366 ​ 54,188 ​ ​ ​ ​ ​ Net loss ​ $ (41,529) ​ $ (44,142) ​ $ (33,951) ​ $ (53,860) ​ ​ ​ ​ ​ Basic and diluted net loss per common share ​ $ (0.59) ​ $ (0.59) ​ $ (0.43) ​ $ (0.68) ​

ORGANIZATION AND SUMMARY OF S_2

ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2019
ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES.
Description of Business	DESCRIPTION OF BUSINESS We are a biopharmaceutical company dedicated to developing and delivering medicines for patients with B-cell mediated diseases, including Chronic Lymphocytic Leukemia (CLL), non-Hodgkin Lymphoma (NHL) and Multiple Sclerosis (MS). We have developed a robust B-cell directed research and development (R&D) platform for identification of key B-cell pathways of interest and rapid clinical testing. Currently, we have five B-cell targeted drug candidates in clinical development, with the lead two therapies, ublituximab (TG-1101) and umbralisib (TGR-1202), in pivotal trials for CLL, NHL and MS. Ublituximab is a novel anti-CD20 monoclonal antibody (mAb) that has been glycoengineered for enhanced potency over first generation antibodies. Umbralisib is an oral, once daily, dual inhibitor of PI3K-delta and CK1-epsilon, which may lead to a differentiated safety profile. When used together in combination therapy, ublituximab and umbralisib are referred to as "U2". Additionally, in early clinical development we have an anti-PD-L1 monoclonal antibody referred to as cosibelimab (TG-1501), an oral Bruton’s Tyrosine Kinase (“BTK”) inhibitor referred to as TG-1701, and an anti-CD47/CD19 bispecific antibody referred to as TG-1801. We also actively evaluate complementary products, technologies and companies for in-licensing, partnership, acquisition and/or investment opportunities. To date, we have not received approval for the sale of any of our drug candidates in any market and, therefore, have not generated any product sales from our drug candidates. ​
Liquidity and Capital Resources	LIQUIDITY AND CAPITAL RESOURCES We have incurred operating losses since our inception, and expect to continue to incur operating losses for the foreseeable future and may never become profitable. As of December 31, 2019, we have an accumulated deficit of $701.2 million. Our major sources of cash have been proceeds from the private placement and public offering of equity securities, and in 2019 from our loan and security agreement executed with Hercules Capital, Inc. (“Hercules”) (See Note 7 for more information). We have not yet commercialized any of our drug candidates and cannot be sure if we will ever be able to do so. Even if we commercialize one or more of our drug candidates, we may not become profitable. Our ability to achieve profitability depends on many factors, including our ability to obtain regulatory approval for our drug candidates; successfully complete any post-approval regulatory obligations; and successfully commercialize our drug candidates alone or in partnership. We may continue to incur substantial operating losses even if we begin to generate revenues from our drug candidates. As of December 31, 2019, we had $140.4 million in cash and cash equivalents, and investment securities. We anticipate that our cash and cash equivalents, and investment securities as of December 31, 2019 will provide sufficient liquidity for more than a twelve-month period from the date of filing this Annual Report on Form 10-K. The actual amount of cash that we will need to operate is subject to many factors, including, but not limited to, the timing, design and conduct of clinical trials for our drug candidates. We are dependent upon significant future financing to provide the cash necessary to execute our current operations, including the commercialization of any of our drug candidates. Our common stock is quoted on the Nasdaq Capital Market and trades under the symbol “TGTX.”
Recently Issued Accounting Standards	RECENTLY ISSUED ACCOUNTING STANDARDS In July 2018, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update (“ASU”) No. 2018-11, “Leases - Targeted Improvements” (“ASU 2018-11”) as an update to ASU 2016-02, Leases (“ASU 2016-02” or “Topic 842”) issued on February 25, 2016. ASU 2016-02 is effective for public business entities for fiscal years beginning January 1, 2019. ASU 2016-02 required companies to adopt the new leases standard at the beginning of the earliest period presented in the financial statements, which is January 1, 2017, using a modified retrospective transition method where lessees must recognize lease assets and liabilities for all leases even though those leases may have expired before the effective date of January 1, 2017. Lessees must also provide the new and enhanced disclosures for each period presented, including the comparative periods. ASU 2018-11 provides an entity with an additional (and optional) transition method to adopt the new leases standard. Under this new transition method, an entity initially applies the new lease standard at the adoption date and recognizes a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. Consequently, an entity’s reporting for the comparative periods presented in the financial statements in which it adopts the new lease standard will continue to be in accordance with ASC 840, Leases (“ASC 840”). An entity that elects this additional (and optional) transition method must provide the required ASC 840 disclosures for all periods that continue to be in accordance with ASC 840. The amendments do not change the existing disclosure requirements in ASC 840. ASU 2018-11 is effective for public business entities for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years, with earlier adoption permitted. The Company adopted ASU 2018-11 on January 1, 2019 using a modified retrospective method and will not restate comparative periods. We elected the package of practical expedients permitted under the transition guidance, which allows us to carryforward our historical lease classification and our assessment on whether a contract is or contains a lease. The adoption of this guidance resulted in the addition of material balances of right of use assets and lease liabilities to our consolidated balance sheets at January 1, 2019, primarily relating to our lease of office space (see Note 8). The impact to our consolidated statements of operations was not material as a result of this standard. In June 2018, the FASB issued ASU No. 2018-07, “Improvements to Nonemployee Share-Based Payment Accounting” (“ASU 2018-07”). ASU 2018-07 expands the scope of FASB Topic 718, Compensation – Stock Compensation (“Topic 718”) to include share-based payment transactions for acquiring goods and services from nonemployees. An entity should only remeasure equity-classified awards for which a measurement date has not been established through a cumulative-effect adjustment to retained earnings as of the beginning of the fiscal year of adoption. Upon transition, the entity is required to measure these nonemployee awards at fair value as of the adoption date. The entity must not remeasure assets that are completed. Disclosures required at transition include the nature of and reason for the change in accounting principle and, if applicable, quantitative information about the cumulative effect of the change on retained earnings or other components of equity. ASU 2018-07 is effective for public business entities for fiscal years beginning after December 15, 2018, including interim periods within that fiscal year. Early adoption is permitted, but no earlier than an entity’s adoption date of Topic 606. The Company adopted ASU 2018-07 on January 1, 2019. The adoption of ASU 2018-07 did not have a material effect on our consolidated financial statements as of January 1, 2019. The adoption of ASU 2018-07 had no impact on nonemployee performance awards as they are measured based on the outcome that is probable. Other pronouncements issued by the FASB or other authoritative accounting standards with future effective dates are either not applicable or not significant to our condensed consolidated financial statements.
Use of Estimates	USE OF ESTIMATES The preparation of financial statements in conformity with U.S. generally accepted accounting principles (“GAAP”) requires management to make estimates and judgments that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the applicable reporting period. On an ongoing basis, we evaluate our estimates and judgments, including those related to accrued expenses and stock-based compensation. Actual results could differ from those estimates. Such differences could be material to the financial statements.
Cash and Cash Equivalents.	CASH AND CASH EQUIVALENTS We treat liquid investments with original maturities of less than three months when purchased as cash and cash equivalents.
Restricted Cash	RESTRICTED CASH We record cash pledged or held in trust as restricted cash. As of December 31, 2019 and 2018, we have approximately $1.3 million of restricted cash pledged to secure a line of credit as a security deposit for an Office Agreement (see Note 8).
Investment Securities.	INVESTMENT SECURITIES Investment securities at both December 31, 2019 and 2018 consist of short-term government securities. We classify these securities as held-to-maturity. Held-to-maturity securities are those securities in which we have the ability and intent to hold the security until maturity. Held-to-maturity securities are recorded at amortized cost, adjusted for the amortization or accretion of premiums or discounts. Premiums and discounts are amortized or accreted over the life of the related held-to-maturity security as an adjustment to yield using the effective interest method. A decline in the market value of any investment security below cost, that is deemed to be other than temporary, results in a reduction in the carrying amount to fair value. The impairment is charged to operations and a new cost basis for the security is established. Other-than-temporary impairment charges are included in interest and other income (expense), net. Dividend and interest income are recognized when earned.
Credit Risk	CREDIT RISK Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents and short-term investments. The Company maintains its cash and cash equivalents and short-term investments with high-credit quality financial institutions. At times, such amounts may exceed federally-insured limits.
Revenue Recognition	REVENUE RECOGNITION Effective January 1, 2018, the Company began recognizing revenue under ASC Topic 606, Revenue from Contracts with Customers ● Step 1: Identify the contract with the customer ● Step 2: Identify the performance obligations in the contract ● Step 3: Determine the transaction price ● Step 4: Allocate the transaction price to the performance obligations in the contract ● Step 5: Recognize revenue when the company satisfies a performance obligation In order to identify the performance obligations in a contract with a customer, a company must assess the promised goods or services in the contract and identify each promised good or service that is distinct. A performance obligation meets ASC 606’s definition of a “distinct” good or service (or bundle of goods or services) if both of the following criteria are met: ● The customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer (i.e., the good or service is capable of being distinct). ● The entity’s promise to transfer the good or service to the customer is separately identifiable from other promises in the contract (i.e., the promise to transfer the good or service is distinct within the context of the contract). If a good or service is not distinct, the good or service is combined with other promised goods or services until a bundle of goods or services is identified that is distinct. The transaction price is the amount of consideration to which an entity expects to be entitled in exchange for transferring promised goods or services to a customer, excluding amounts collected on behalf of third parties (for example, some sales taxes). The consideration promised in a contract with a customer may include fixed amounts, variable amounts, or both. Variable consideration is included in the transaction price only to the extent that it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is subsequently resolved. The transaction price is allocated to each performance obligation on a relative standalone selling price basis. The transaction price allocated to each performance obligation is recognized when that performance obligation is satisfied, at a point in time or over time as appropriate.
Research and Development Costs	RESEARCH AND DEVELOPMENT COSTS Generally, research and development costs are expensed as incurred. Nonrefundable advance payments for goods or services that will be used or rendered for future research and development activities are deferred and amortized over the period that the goods are delivered or the related services are performed, subject to an assessment of recoverability. We make estimates of costs incurred in relation to external clinical research organizations, or CROs, and clinical site costs. We analyze the progress of clinical trials, including levels of patient enrollment, invoices received and contracted costs when evaluating the adequacy of the amount expensed and the related prepaid asset and accrued liability. Significant judgments and estimates must be made and used in determining the accrued balance and expense in any accounting period. We review and accrue CRO expenses and clinical trial study expenses based on work performed and rely upon estimates of those costs applicable to the stage of completion of a study. Accrued CRO costs are subject to revisions as such trials progress to completion. Revisions are charged to expense in the period in which the facts that give rise to the revision become known. With respect to clinical site costs, the financial terms of these agreements are subject to negotiation and vary from contract to contract. Payments under these contracts may be uneven, and depend on factors such as the achievement of certain events, the successful recruitment of patients, the completion of portions of the clinical trial or similar conditions. The objective of our policy is to match the recording of expenses in our financial statements to the actual services received and efforts expended. As such, expense accruals related to clinical site costs are recognized based on our estimate of the degree of completion of the event or events specified in the specific clinical study or trial contract. Prepaid research and development in our consolidated balance sheets includes, among other things, costs related to agreements with CRO’s, certain costs to third party service providers related to development and manufacturing services as well as clinical development. These agreements often require payments in advance of services performed or goods received. Accordingly, as of December 31, 2019 and December 31, 2018, we recorded approximately $8.1 million and $9.7 million, respectively, in prepaid research and development related to such advance agreements.
Income Taxes.	INCOME TAXES Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to temporary differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases, operating losses and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in operations in the period that includes the enactment date. If the likelihood of realizing the deferred tax assets or liability is less than “more likely than not,” a valuation allowance is then created. We, and our subsidiaries, file income tax returns in the U.S. Federal jurisdiction and in various states. We have tax net operating loss carryforwards that are subject to examination for a number of years beyond the year in which they were generated for tax purposes. Since a portion of these net operating loss carryforwards may be utilized in the future, many of these net operating loss carryforwards will remain subject to examination. We recognize interest and penalties related to uncertain income tax positions in income tax expense. Refer to Note 9 for further information on impact of tax reform.
Stock-Based Compensation	STOCK-BASED COMPENSATION We recognize all stock-based payments to employees and non-employee directors (as compensation for service) as noncash compensation expense in the consolidated financial statements based on the fair values of such payments. Stock-based compensation expense recognized each period is based on the value of the portion of stock-based payment awards that is ultimately expected to vest during the period. Forfeitures are recognized as they occur. In addition, because some of the options, restricted stock and warrants issued to employees, consultants and other third parties vest upon achievement of certain milestones, the total expense is uncertain. Compensation expense for such awards that vest upon the achievement of milestones is recognized when the achievement of such milestones becomes probable.
Basic and Diluted Net Loss Per Common Share	BASIC AND DILUTED NET LOSS PER COMMON SHARE Basic net loss per share of our common stock is calculated by dividing net loss applicable to the common stock by the weighted-average number of our common stock outstanding for the period. Diluted net loss per share of common stock is the same as basic net loss per share of common stock since potentially dilutive securities from stock options, stock warrants and convertible preferred stock would have an antidilutive effect either because we incurred a net loss during the period presented or because such potentially dilutive securities were out of the money and the Company realized net income during the period presented. The amounts of potentially dilutive securities excluded from the calculation were 8,361,739, 6,528,932 and 4,835,706 at December 31, 2019, 2018 and 2017, respectively. During the years ended December 31, 2019, 2018 and 2017, the Company incurred a net loss, therefore, all of the securities are antidilutive and excluded from the computation of diluted loss per share. ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2019 2018 2017 Unvested restricted stock 5,591,786 4,595,689 4,820,143 Options 2,605,730 1,916,900 — Shares issuable upon note conversion 17,165 16,343 15,563 Warrants 147,058 — — Total 8,361,739 6,528,932 4,835,706
Long-Lived Assets and Goodwill	LONG-LIVED ASSETS AND GOODWILL Long-lived assets are reviewed for potential impairment when circumstances indicate that the carrying value of long-lived tangible and intangible assets with finite lives may not be recoverable. Management’s policy in determining whether an impairment indicator exists, a triggering event, comprises measurable operating performance criteria as well as qualitative measures. If an analysis is necessitated by the occurrence of a triggering event, we make certain assumptions in determining the impairment amount. If the carrying amount of an asset exceeds its estimated future cash flows, an impairment charge is recognized. Goodwill is reviewed for impairment annually, or earlier when events arise that could indicate that an impairment exists. We test for goodwill impairment using a two-step process. The first step compares the fair value of the reporting unit with the unit’s carrying value, including goodwill. When the carrying value of the reporting unit is greater than fair value, the unit’s goodwill may be impaired, and the second step must be completed to measure the amount of the goodwill impairment charge, if any. In the second step, the implied fair value of the reporting unit’s goodwill is compared with the carrying amount of the unit’s goodwill. If the carrying amount is greater than the implied fair value, the carrying value of the goodwill must be written down to its implied fair value. We will continue to perform impairment tests annually, at December 31, and whenever events or changes in circumstances suggest that the carrying value of an asset may not be recoverable. There was no impairment to goodwill as of December 31, 2019.

ORGANIZATION AND SUMMARY OF S_3

ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	12 Months Ended
	Dec. 31, 2019
Organization And Summary Of Significant Accounting Policies
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2019 2018 2017 Unvested restricted stock 5,591,786 4,595,689 4,820,143 Options 2,605,730 1,916,900 — Shares issuable upon note conversion 17,165 16,343 15,563 Warrants 147,058 — — Total 8,361,739 6,528,932 4,835,706

CASH AND CASH EQUIVALENTS (Tabl

CASH AND CASH EQUIVALENTS (Tables)	12 Months Ended
	Dec. 31, 2019
CASH. AND CASH EQUIVALENTS.
Schedule of Cash and Cash Equivalents	The following tables summarize our cash and cash equivalents at December 31, 2019 and 2018: ​ ​ ​ ​ ​ ​ ​ ​ December 31, December 31, (in thousands) ​ 2019 ​ 2018 ​ ​ ​ ​ ​ Checking and bank deposits $ 110,135 $ 39,268 Money market funds ​ ​ 2,502 ​ ​ 2,690 Total ​ $ 112,637 ​ $ 41,958

INVESTMENT SECURITIES (Tables)

INVESTMENT SECURITIES (Tables)	12 Months Ended
	Dec. 31, 2019
INVESTMENT SECURITIES
Schedule of held-to-maturity securities	The following tables summarize our investment securities at December 31, 2019 and 2018: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ Amortized ​ Gross ​ Gross ​ ​ ​ ​ ​ cost, as ​ unrealized ​ unrealized ​ Estimated (in thousands) adjusted holding gains holding losses fair value Short-term investments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Obligations of domestic governmental agencies (maturing between January 2020 and September 2020) (held-to-maturity) ​ $ 27,798 ​ $ 28 ​ $ — ​ $ 27,826 Total short-term investment securities ​ $ 27,798 ​ $ 28 ​ $ — ​ $ 27,826 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2018 ​ Amortized Gross Gross ​ ​ ​ ​ cost, as ​ unrealized ​ unrealized ​ Estimated ​ ​ adjusted ​ holding gains ​ holding losses ​ fair value Short-term investments: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Obligations of domestic governmental agencies (maturing between January 2019 and November 2019) (held-to-maturity) ​ $ 26,943 ​ $ 2 ​ $ 10 ​ $ 26,935 Total short-term investment securities ​ $ 26,943 ​ $ 2 ​ $ 10 ​ $ 26,935

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	12 Months Ended
	Dec. 31, 2019
FAIR VALUE MEASUREMENTS
Schedule of fair value, liabilities measured on recurring and nonrecurring basis	The following tables provide the fair value measurements of applicable financial liabilities as of December 31, 2019 and 2018: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Financial liabilities at fair value as of December 31, 2019 (in thousands) Level 1 Level 2 Level 3 Total ​ ​ ​ ​ ​ ​ ​ ​ ​ 5% Notes ​ $ — ​ $ — ​ $ 190 ​ $ 190 Total ​ $ — ​ $ — ​ $ 190 ​ $ 190 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Financial liabilities at fair value as of December 31, 2018 ​ Level 1 Level 2 Level 3 Total ​ ​ ​ ​ ​ 5% Notes ​ $ — ​ $ — ​ $ 67 ​ $ 67 Total ​ $ — ​ $ — ​ $ 67 ​ $ 67
Schedule of change in level three fair value during period	The following table summarizes the changes in Level 3 instruments for the years ended December 31, 2018 and 2019: ​ ​ ​ ​ (in thousands) ​ ​ ​ Balance at January 1, 2018 $ 128 Interest accrued on face value of 5% Notes ​ 878 Conversion of 5% Notes ​ — Change in fair value of Level 3 liabilities ​ (939) Balance at December 31, 2018 ​ 67 Interest accrued on face value of 5% Notes ​ 924 Conversion of 5% Notes ​ — Change in fair value of Level 3 liabilities ​ (801) Balance at December 31, 2019 ​ $ 190

STOCKHOLDERS' EQUITY (Tables)

STOCKHOLDERS' EQUITY (Tables)	12 Months Ended
	Dec. 31, 2019
STOCKHOLDERS' EQUITY
Schedule Of Stock Options Activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ ​ ​ ​ ​ ​ ​ average ​ ​ ​ ​ ​ ​ ​ Weighted- ​ Contractual ​ ​ ​ ​ ​ Number of ​ average ​ Term ​ Aggregate ​ ​ shares ​ exercise price ​ (in years) ​ intrinsic value ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Outstanding at December 31, 2017 — ​ ​ — ​ — ​ $ — Granted 1,916,900 ​ $ 6.50 ​ ​ ​ Exercised — ​ — ​ ​ ​ Forfeited — ​ — ​ ​ ​ Expired — ​ ​ — ​ ​ ​ Outstanding at December 31, 2018 ​ 1,916,900 ​ $ 6.50 ​ 9.75 ​ $ — Granted ​ 815,000 ​ ​ 7.18 ​ ​ ​ ​ ​ Exercised ​ — ​ ​ — ​ ​ ​ ​ ​ Forfeited ​ (126,170) ​ ​ 6.10 ​ ​ ​ ​ ​ Expired ​ — ​ ​ — ​ ​ ​ ​ ​ Outstanding at December 31, 2019 ​ 2,605,730 ​ $ 6.73 ​ 8.92 ​ $ 11,706,110 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Vested and expected to vest at December 31, 2019 2,605,730 ​ $ 6.73 8.92 ​ $ 11,706,110
Schedule of Fair Value Assumptions	The fair value of the Company’s option awards were estimated using the assumptions below: ​ ​ ​ ​ ​ ​ ​ ​ Year ended ​ ​ ​ December 31, ​ December 31, ​ ​ 2019 ​ 2018 Volatility 172.99-291.61 192.76-296.71 ​ Expected term (in years) 5.0-6.25 5.0-6.25 ​ Risk-free rate 1.82-2.49 % 2.49-2.56 % Expected dividend yield -- ​ -- ​
Schedule of Nonvested Restricted Stock Units Activity	​ ​ ​ ​ ​ ​ ​ ​ Weighted Average ​ ​ ​ ​ Grant Date Fair ​ ​ Number of Shares ​ Value Outstanding at January 1, 2017 8,642,055 $ 7.20 Granted 1,836,511 ​ 6.40 Vested (4,103,048) ​ 5.24 Forfeited (53,875) ​ 8.47 Outstanding at December 31, 2017 6,321,643 ​ 7.17 Granted 1,562,211 ​ 13.07 Vested (1,596,966) ​ 9.38 Forfeited (191,196) ​ 8.13 Outstanding at December 31, 2018 6,095,692 ​ ​ 8.07 Granted 1,851,520 ​ 12.95 Vested (738,960) ​ 9.08 Forfeited (116,463) ​ 7.96 Outstanding at December 31, 2019 7,091,789 ​ $ 7.78 ​ ​ ​ ​ ​ ​
Schedule Of Warrants Activity	The following table summarizes warrant activity for the years ended December 31, 2019, 2018 and 2017: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ ​ ​ ​ ​ ​ average exercise ​ Aggregate ​ ​ Warrants ​ price ​ intrinsic value Outstanding at January 1, 2017 913,379 ​ $ 2.41 ​ $ 1,961,403 Issued — ​ — ​ ​ Exercised (887,585) ​ 2.41 ​ ​ Expired (25,794) ​ — ​ ​ Outstanding at December 31, 2017 — ​ — ​ ​ — Issued — ​ — ​ ​ Exercised — ​ — ​ ​ Expired — ​ — ​ ​ Outstanding at December 31, 2018 — ​ ​ — ​ ​ — Issued 147,058 ​ 4.08 ​ ​ Exercised — ​ — ​ ​ Expired — ​ — ​ ​ Outstanding at December 31, 2019 147,058 ​ $ 4.08 ​ $ 1,032,347

OTHER LIABILITIES (Tables)

OTHER LIABILITIES (Tables)	12 Months Ended
	Dec. 31, 2019
OTHER LIABILITIES
Schedule of Debt	The following is a summary of notes payable included in other current liabilities on the Company's consolidated balance sheet: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ (in thousands) ​ December 31, 2019 ​ December 31, 2018 ​ ​ ​ ​ Non- ​ ​ ​ ​ ​ ​ Non- ​ ​ ​ ​ ​ Current ​ current ​ ​ ​ ​ Current ​ current ​ ​ ​ ​ ​ portion, ​ portion, ​ ​ ​ ​ portion, ​ portion, ​ ​ ​ ​ net net Total net net Total Convertible 5% Notes Payable ​ $ 190 ​ $ — ​ $ 190 ​ $ 67 ​ $ — ​ $ 67 Totals ​ $ 190 ​ $ — ​ $ 190 ​ $ 67 ​ $ — ​ $ 67

LONG-TERM DEBT (Tables)

LONG-TERM DEBT (Tables)	12 Months Ended
	Dec. 31, 2019
LONG-TERM DEBT.
Schedule of key assumptions	The Company estimated the fair value of the Hercules Warrant using the Black-Scholes model based on the following key assumptions: ​ ​ ​ ​ ​ Exercise Price $ 4.08 Common share price on date of issuance ​ $ 6.80 ​ Volatility ​ 195.9 % Risk-free interest rate ​ 2.63 % Expected dividend yield ​ -- % Contractual term (in years) ​ 7.00 years ​
Schedule of long-term debt	Long-term debt as of December 31, 2019, is as follows (in thousands): ​ ​ ​ ​ ​ December 31, ​ 2019 Long-term debt ​ $ 30,000 End of term fee ​ 975 ​ ​ 30,975 Less: unamortized debt issuance costs ​ (2,005) ​ ​ 28,970 Less: Current portion ​ — Long-term debt non-current ​ $ 28,970

LEASES (Tables)

LEASES (Tables)	12 Months Ended
	Dec. 31, 2019
LEASES
Schedule of lease cost	The following components of lease expense are included in the Company’s consolidated statements of operations for the year ended December 31, 2019 and 2018: ​ ​ ​ ​ ​ ​ ​ ​ December 31, December 31, (in thousands) 2019 2018 Operating lease cost ​ $ 2,651 ​ $ 1,440 Net lease cost ​ $ 2,651 ​ $ 1,440
Schedule of classification of lease liabilities	The balance sheet classification of lease liabilities was as follows: ​ ​ ​ ​ ​ December 31, (in thousands) 2019 Liabilities ​ Lease liability current portion ​ $ 1,616 Lease liability non-current ​ 10,218 Total lease liability ​ $ 11,834
Schedule of lease liability maturity	As of December 31, 2019, the maturities of lease liabilities were as follows: ​ ​ ​ ​ ​ Operating (in thousands) ​ leases 2020 ​ $ 1,804 2021 ​ 1,874 2022 ​ 1,911 2023 ​ 1,913 2024 ​ 1,796 After 2024 ​ 10,615 Total lease payments ​ 19,913 Less: Interest ​ (8,079) Present value of lease liabilities(*) ​ $ 11,834

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2019
INCOME. TAXES.
Schedule of Deferred Tax Assets and Liabilities	The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities at December 31, 2019 and 2018 are presented below. ​ ​ ​ ​ ​ ​ ​ (in thousands) 2019 2018 Deferred tax assets: ​ ​ Net operating loss carryforwards ​ $ 158,177 ​ $ 122,678 Research and development credit ​ 22,483 ​ 15,217 Noncash compensation ​ 4,680 ​ 4,394 Disallowed interest ​ ​ 710 ​ ​ — Other ​ 661 ​ 658 Deferred tax asset, excluding valuation allowance ​ 186,711 ​ 142,947 ​ ​ ​ ​ ​ ​ ​ Less valuation allowance ​ (186,711) ​ (142,947) Net deferred tax assets ​ $ — ​ $ —
Schedule of Effective Income Tax Rate Reconciliation	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year ended December 31, (in thousands) 2019 2018 2017 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Loss before income taxes, as reported in the consolidated statements of operations ​ $ (172,871) ​ $ (173,482) ​ $ (118,476) ​ ​ ​ ​ ​ Computed “expected” tax benefit ​ $ (36,303) ​ $ (36,431) ​ ​ (40,282) ​ ​ ​ ​ ​ Increase (decrease) in income taxes resulting from: ​ ​ ​ ​ Expected benefit from state and local taxes ​ (2,128) ​ (2,243) ​ (1,106) Research and development credits ​ (7,266) ​ (4,726) ​ (3,697) Other ​ 641 ​ 639 ​ 1,563 Stock options ​ 1,292 ​ (473) ​ 8,213 Enactment of federal tax reform ​ — ​ — ​ 51,768 Change in the balance of the valuation allowance for deferred tax assets ​ 43,764 ​ 43,234 ​ (16,459) ​ ​ $ — ​ $ — ​ $ —

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	12 Months Ended
	Dec. 31, 2019
COMMITMENTS AND CONTINGENCIES
Schedule of Loss Contingencies by Contingency	As of December 31, 2019, we have known contractual obligations; commitments and contingencies of $97.6 million related to our long term liabilities and operating lease obligations. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Less than 1 ​ ​ ​ ​ ​ ​ ​ More than Payment due by period (in thousands) Total year 1-3 years 3-5 years 5 years Contractual obligations ​ ​ ​ ​ ​ Operating leases ​ $ 20,440 ​ $ 2,331 ​ $ 3,785 ​ $ 3,709 ​ $ 10,615 Long-term debt ​ ​ 30,000 ​ ​ — ​ ​ 30,000 ​ ​ — ​ ​ — Contract manufacturer ​ 47,168 ​ 47,168 ​ — ​ — ​ — Total ​ $ 97,608 ​ $ 49,499 ​ $ 33,785 ​ $ 3,709 ​ $ 10,615

QUARTERLY FINANCIAL INFORMATI_2

QUARTERLY FINANCIAL INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2019
Table Text Block Supplement [Abstract]
Schedule of Quarterly Financial Information	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 3 Months Ended ​ ​ March 31, ​ June 30, ​ September 30, ​ December 31, (in thousands) 2019 2019 2019 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ License revenue ​ $ 38 ​ $ 38 ​ $ 38 ​ $ 38 ​ ​ ​ ​ ​ Total costs and expenses ​ 34,727 ​ 35,582 ​ 60,899 ​ 37,998 ​ ​ ​ ​ ​ Net loss ​ $ (35,156) ​ $ (36,213) ​ $ (61,930) ​ $ (39,571) ​ ​ ​ ​ ​ ​ Basic and diluted net loss per common share ​ $ (0.43) ​ $ (0.42) ​ $ (0.69) ​ $ (0.44) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 3 Months Ended ​ March 31, June 30, September 30, December 31, (in thousands) ​ 2018 ​ 2018 ​ 2018 ​ 2018 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ License revenue ​ $ 38 ​ $ 38 ​ $ 38 ​ $ 38 ​ ​ ​ ​ ​ Total costs and expenses ​ 41,615 ​ 44,383 ​ 34,366 ​ 54,188 ​ ​ ​ ​ ​ Net loss ​ $ (41,529) ​ $ (44,142) ​ $ (33,951) ​ $ (53,860) ​ ​ ​ ​ ​ Basic and diluted net loss per common share ​ $ (0.59) ​ $ (0.59) ​ $ (0.43) ​ $ (0.68)

ORGANIZATION AND SUMMARY OF S_4

ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES.
Accumulated deficit	$ 701,216	$ 528,345
Restricted Cash and Investments	1,300	1,300
Prepaid Manufacturing	8,100	$ 9,700
Cash and cash equivalents, and investment securities	140,400
Impairment to goodwill	$ 0

ORGANIZATION AND SUMMARY OF S_5

ORGANIZATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Computation of diluted loss per share (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from calculation	8,361,739	6,528,932	4,835,706
Unvested restricted stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from calculation	5,591,786	4,595,689	4,820,143
Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from calculation	2,605,730	1,916,900	0
Share Issuable Upon Note Conversion [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from calculation	17,165	16,343	15,563
Warrant [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities excluded from calculation	147,058	0	0

CASH AND CASH EQUIVALENTS - Sum

CASH AND CASH EQUIVALENTS - Summary of cash and cash equivalents (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
CASH. AND CASH EQUIVALENTS.
Checking and bank deposits	$ 110,135	$ 39,268
Money market funds	2,502	2,690
Total	$ 112,637	$ 41,958	$ 56,718

INVESTMENT SECURITIES - Summary

INVESTMENT SECURITIES - Summary of investment securities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Amortized cost, as adjusted	$ 27,798	$ 26,943
Gross unrealized holding gains	28	2
Gross unrealized holding losses	0	10
Estimated fair value	27,826	26,935
Short-term Investments [Member] | US Government Agencies Debt Securities [Member]
Amortized cost, as adjusted	27,798	26,943
Gross unrealized holding gains	28	2
Gross unrealized holding losses	0	10
Estimated fair value	$ 27,826	$ 26,935

FAIR VALUE MEASUREMENTS - Finan

FAIR VALUE MEASUREMENTS - Financial liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
5% Notes	$ 190	$ 67
Totals	190	67
Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
5% Notes	0	0
Totals	0	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
5% Notes	0	0
Totals	0	0
Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
5% Notes	190	67
Totals	$ 190	$ 67

FAIR VALUE MEASUREMENTS - Summa

FAIR VALUE MEASUREMENTS - Summary of changes in Level 3 instruments (Details) - Fair Value, Inputs, Level 3 [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Balance at January	$ 67	$ 128
Interest accrued on face value of 5% Notes	924	878
Conversion of 5% Notes	0	0
Change in fair value of Level 3 liabilities	(801)	(939)
Balance at December	$ 190	$ 67

FAIR VALUE MEASUREMENTS (Detail

FAIR VALUE MEASUREMENTS (Details) $ / shares in Units, $ in Millions	1 Months Ended	12 Months Ended
	Mar. 31, 2010USD ($)$ / shares	Dec. 31, 2019USD ($)paymentitem	Dec. 31, 2018USD ($)item
Fair Value Measurement [Line Items]
Cumulative Liability		$ 19.3	$ 18.4
Manhattan and Ariston Pharmaceuticals Merger [Member]
Fair Value Measurement [Line Items]
Notes Issued	$ 15.5
Debt Instrument convertible conversion price | $ / shares	$ 1,125
Percentage Of Cash Proceeds From Operation To Repay Convertible Debt	50.00%
Debt Instrument, Term	5 years
Debt instrument period	5.00%
Convertible Notes Payable [Member]
Fair Value Measurement [Line Items]
Cumulative Liability		$ 19.3	$ 18.4
Debt Instrument convertible conversion price | $ / shares	$ 1,125
Percentage Of Cash Proceeds From Operation To Repay Convertible Debt	50.00%
Debt instrument period	5.00%	5.00%	5.00%
Number of payments | payment		0
Number of obligations | item		0	0

STOCKHOLDERS' EQUITY - Stock op

STOCKHOLDERS' EQUITY - Stock option activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Equity Incentive Plans Stock Option Activity [Line Items]
Number of shares, Outstanding Beginning Balance	1,916,900
Number of shares, Outstanding Ending Balance	2,605,730	1,916,900
Weighted - average Contractual Term (in years)	8 years 11 months 1 day	9 years 9 months
Weighted - average Contractual Term, Exercisable at December 31 (in years)	8 years 11 months 1 day
Employee Stock Option [Member]
Equity Incentive Plans Stock Option Activity [Line Items]
Number of shares, Outstanding Beginning Balance	1,916,900	0
Number of shares, Granted.	815,000	1,916,900
Number of shares, Exercised		0
Number of shares, Forfeited	(126,170)	0
Number of shares, Expired	0	0
Number of shares, Outstanding Ending Balance	2,605,730	1,916,900
Number of shares, Exercisable at December 31	2,605,730
Weighted - average exercise price, Outstanding Beginning Balance	$ 6.50	$ 0
Weighted - average exercise price, Granted	7.18	6.50
Weighted - average exercise price, Exercised		0
Weighted - average exercise price, Forfeited	6.10	0
Weighted - average exercise price, Expired	0	0
Weighted - average exercise price, Outstanding Ending Balance	6.73	$ 6.50
Weighted - average exercise price, Exercisable at December 31	$ 6.73
Aggregate Intrinsic Value, Outstanding at December 31	$ 11,706,110	$ 0	$ 0
Aggregate Intrinsic Value, Exercisable at December 31	$ 11,706,110

STOCKHOLDERS' EQUITY - Fair val

STOCKHOLDERS' EQUITY - Fair value assumptions of options (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Volatility, minimum	172.99%	192.76%
Volatility, maximum	291.61%	296.71%
Risk-free rate, minimum	1.82%	2.49%
Risk-free rate, maximum	2.49%	2.56%
Minimum [Member]
Expected term (in years)	5 years	5 years
Maximum [Member]
Expected term (in years)	6 years 3 months	6 years 3 months

STOCKHOLDERS' EQUITY - Summary

STOCKHOLDERS' EQUITY - Summary of restricted shares (Details) - Unvested restricted stock [Member] - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Equity Incentive Plans Restricted Stock Activity [Line Items]
Number of Shares, Outstanding at Begining Balance	6,095,692	6,321,643	8,642,055
Number of Shares, Granted	1,851,520	1,562,211	1,836,511
Number of Shares, Vested	(738,960)	(1,596,966)	(4,103,048)
Number of Shares, Forfeited	(116,463)	(191,196)	(53,875)
Number of Shares, Outstanding at Ending Balance	7,091,789	6,095,692	6,321,643
Weighted Average Grant Date Fair Value, Outstanding at Beginning Balance	$ 8.07	$ 7.17	$ 7.20
Weighted Average Grant Date Fair Value, Granted	12.95	13.07	6.40
Weighted Average Grant Date Fair Value, Vested	9.08	9.38	5.24
Weighted Average Grant Date Fair Value, Forfeited	7.96	8.13	8.47
Weighted Average Grant Date Fair Value, Outstanding at Ending Balance	$ 7.78	$ 8.07	$ 7.17

STOCKHOLDERS' EQUITY - Warrant

STOCKHOLDERS' EQUITY - Warrant activity (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Stockholders' Equity [Abstract]
Warrants, Outstanding at Beginning Balance	0	0	913,379
Warrants, Issued	147,058	0	0
Warrants, Exercised	0	0	887,585
Warrants, Expired	0	0	25,794
Warrants, Outstanding at Ending Balance	147,058	0	0
Weighted - average exercise price of Warrants, Outstanding at Beginning Balance	$ 0	$ 0	$ 2.41
Weighted - average exercise price of Warrants, Issued	4.08	0	0
Weighted - average exercise price of Warrants, Exercised	0	0	2.41
Weighted - average exercise price of Warrants, Expired	0	0	0
Weighted - average exercise price of Warrants, Outstanding at Ending Balance	$ 4.08	$ 0	$ 0
Aggregate Intrinsic Value of Warrants, Outstanding at Beginning Balance	$ 0	$ 0	$ 1,961,403
Aggregate Intrinsic Value of Warrants, Outstanding at Ending Balance	$ 1,032,347	$ 0	$ 0

STOCKHOLDERS' EQUITY (Details)

STOCKHOLDERS' EQUITY (Details) - USD ($)	Dec. 22, 2019	Mar. 01, 2019	Jan. 01, 2017	Jul. 28, 2014	Jul. 18, 2014	Jun. 30, 2018	May 31, 2017	Mar. 31, 2017	Dec. 31, 2014	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2015	Dec. 31, 2016
Number of rights for each outstanding share of common stock				1
Number of shares each right entitles registered holder to purchase				0.0001
Number of days after which right become exercisable				10 days
Preferred stock, purchase price				$ 100
Preferred stock, shares authorized										10,000,000	10,000,000
Preferred stock, par value (in dollars per share)										$ 0.001	$ 0.001
Common stock, par value (in dollars per share)										$ 0.001	$ 0.001
Stock Issued During Period, Shares, New Issues	5,434,783	4,100,000						769,230
Period of underwriter overallotment option								30 days
Payments of underwriting discounts and offering expenses		$ 200,000						$ 3,600,000
Incremental stock Based compensation expense			$ 0
Options outstanding										2,605,730	1,916,900
Share Price	$ 9.20	$ 5.87						$ 9.75
Net proceeds		$ 27,500,000
Proceeds from offering	$ 50,000,000							$ 54,000,000
Common stock that remains available for sale										$ 9,500,000
Common Stock, Shares Authorized										150,000,000	150,000,000
Percent of commission rate							3.00%		3.00%
Number of years before Rights will expire					10 years
Expenses on stock options								$ 5,128,206		$ 7,800,000	$ 12,900,000	$ 15,900,000
Total unrecognized compensation expense related to unvested time-based restricted stock										$ 15,300,000
Weighted-average period of recognition for total unrecognized compensation expense related to unvested time-based restricted stock										1 year
Recognized stock based compensation expense										$ 11,335,000	$ 12,886,000	$ 15,945,000
Treasury Stock, Shares										41,309	41,309
Treasury Stock, Value										$ 234,000	$ 234,000
Class of Warrant or Right, Outstanding										0	0	0
Over-Allotment Option [Member]
Stock Issued During Period, Shares, New Issues		615,000
Period of underwriter overallotment option		30 days
2015 ATM [Member]
Stock Issued During Period, Shares, New Issues												3,104,253
Gross proceeds												$ 31,600,000
Share Price												$ 10.18
Proceeds from offering												$ 31,000,000
2017 ATM [Member]
Stock Issued During Period, Shares, New Issues										13,620,165	9,025,222
Gross proceeds										$ 99,300,000	$ 115,800,000
Share Price										$ 7.29	$ 12.83
Net proceeds										$ 97,500,000	$ 113,700,000
Series A Preferred Stock [Member]
Preferred stock, par value (in dollars per share)										$ 0.001	$ 0.001
Minimum [Member]
Market capitalization thresholds			375,000,000
Maximum [Member]
Market capitalization thresholds			$ 750,000,000
Proceeds from offering							$ 300,000,000		$ 250,000,000				$ 175,000,000
Share-based Payment Arrangement, Nonemployee [Member]
Restricted stock outstanding										2,021,250
Employee Stock Option [Member]
Expenses on stock options										$ 3,500,000	$ 0	$ 0
Total unrecognized compensation expense related to unvested time-based restricted stock										$ 2,600,000
Weighted-average period of recognition for total unrecognized compensation expense related to unvested time-based restricted stock										1 year 6 months
Recognized stock based compensation expense										$ 300,000
Unvested restricted stock [Member]
Number of shares granted										1,851,520	1,562,211	1,836,511
Restricted stock outstanding										7,091,789	6,095,692	6,321,643		8,642,055
Milestone Based Restricted Stock [Member]
Restricted stock outstanding										1,103,011
Amended and Restated 2012 Incentive Plan [Member]
Number of shares added to the plan						6,000,000
Number of additional shares that may be issued											779,346
Amended and Restated 2012 Incentive Plan [Member] | Caribe BioAdvisors, L L C [Member] | Unvested restricted stock [Member]
Number of shares granted			2,960,000
Amended and Restated 2012 Incentive Plan [Member] | Michael S. Weiss Executive Chairman And Chief Executive Officer And President [Member] | Unvested restricted stock [Member]
Number Of previously granted shares agreed to be forfeited			3,381,866
Vesting period of previously granted shares			3 years
Number of shares granted			418,371

OTHER LIABILITIES - Notes payab

OTHER LIABILITIES - Notes payables in other current liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Notes payable, Current portion, net	$ 190	$ 67
Notes Payable, Noncurrent, net	0	0
Notes Payable.	190	67
Convertible Notes [Member]
Notes payable, Current portion, net	190	67
Notes Payable, Noncurrent, net	0	0
Notes Payable.	$ 190	$ 67

OTHER LIABILITIES (Details)

OTHER LIABILITIES (Details) - USD ($)	1 Months Ended	3 Months Ended	12 Months Ended
	Mar. 31, 2010	Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cumulative Liability			$ 19,300,000	$ 18,400,000
Interest Expenses			1,200,000
Construction Contract Cost, Progress Payment Offset			$ 0
Percentage Of Administrative Fee			6.00%
Agreement costs included in current liabilities			$ 47,200,000	18,400,000
Subsequent Event [Member]
Agreement costs included in current liabilities		$ 19,600,000
Convertible Notes Payable [Member]
Cumulative Liability			19,300,000	$ 18,400,000
Construction Contract Cost, Progress Payment Offset			$ 0
Det instrument rate	5.00%		5.00%	5.00%
Percentage Of Cash Proceeds From Operation To Repay Convertible Debt	50.00%
Debt Instrument convertible conversion price	$ 1,125

LONG-TERM DEBT - Estimated fair

LONG-TERM DEBT - Estimated fair value of warrants (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 22, 2019	Mar. 01, 2019	Mar. 31, 2017
Common share price on date of issuance		$ 9.20	$ 5.87	$ 9.75
Warrant [Member] | Measurement Input, Exercise Price [Member]
Exercise Price	$ 4.08
Warrant [Member] | Measurement Input, Share Price [Member]
Common share price on date of issuance	$ 6.80
Warrant [Member] | Measurement Input, Price Volatility [Member]
Volatility	195.90%
Warrant [Member] | Measurement Input, Risk Free Interest Rate [Member]
Risk-free interest rate	2.63%
Warrant [Member] | Measurement Input, Expected Term [Member]
Warrants, contractual term	7 years

LONG-TERM DEBT - Summary of lon

LONG-TERM DEBT - Summary of long term debt (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
LONG-TERM DEBT.
Long-term debt	$ 30,000
End of term fee	975
Long-term debt, gross	30,975
Less: unamortized debt issuance costs	(2,005)
Long-term Debt	28,970
Less: Current portion	0
Long-term debt non-current	$ 28,970	$ 0

LONG-TERM DEBT (Details)

LONG-TERM DEBT (Details) $ / shares in Units, $ in Thousands	Feb. 28, 2019USD ($)installmentDloan	Dec. 31, 2019USD ($)$ / sharesshares	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Jul. 28, 2014$ / sharesshares
Debt Instrument [Line Items]
Warrants issued | shares					0.0001
Amortization of Debt Issuance Costs		$ 772	$ 0	$ 0
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares					$ 100
Class Of Warrant Or Right Fair Value		1,000
Unamortized Debt Issuance Expense		$ 2,005
Warrant [Member]
Debt Instrument [Line Items]
Warrant coverage percentage		2.00%
Warrants issued | shares		147,058
Warrant exercisable term		7 years
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares		$ 4.08
Financing expenses, Hercules Loan Agreement		$ 2,800
Term Loan [Member]
Debt Instrument [Line Items]
Maximum term loan facility	$ 60,000
Amount drawn on first advance	30,000
Debt Instrument, Fourth Advance Available	$ 10,000
Number of additional advances | loan	2
Additional Advances Drawn	$ 10,000
Minimum incremental borrowings	5,000
Minimum amount raised from unrestricted cash proceeds	$ 150,000
Number of amortization payments installments | installment	18
Number of interest only payments installments | installment	12
Number of business days | D	7
Expected prepayment on outstanding advances	$ 5,000
Prepayment charge (as a percent)	3.50%
Interest on past due outstanding (as a percent)	4.00%
Minimum Indebtness involved by the borrower in default	$ 750
Term Loan [Member] | Within First twelve Months Of Closing Date [Member]
Debt Instrument [Line Items]
Prepayment charge (as a percent)	3.00%
Term Loan [Member] | After Twelve Months But On Or Before Twenty Four Months [Member]
Debt Instrument [Line Items]
Prepayment charge (as a percent)	1.50%
Term Loan [Member] | After Twenty Four Months Of Closing Date [Member]
Debt Instrument [Line Items]
Prepayment charge (as a percent)	0.00%
Term Loan [Member] | Maximum [Member]
Debt Instrument [Line Items]
Number of advances | loan	4
Prime Rate [Member] | Minimum [Member]
Debt Instrument [Line Items]
Interest rate ( as a percent)	4.75%
Prime Rate [Member] | Maximum [Member]
Debt Instrument [Line Items]
Interest rate ( as a percent)	10.25%

LEASES - Components of lease ex

LEASES - Components of lease expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
LEASES
Operating lease cost	$ 2,651
Operating lease cost		$ 1,440
Net lease cost	$ 2,651
Net lease cost		$ 1,440

LEASES - Classification of leas

LEASES - Classification of lease liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
LEASES
Lease liability current portion	$ 1,616
Lease liability non-current	10,218	$ 0
Total lease liability	$ 11,834

LEASES - Maturities of lease li

LEASES - Maturities of lease liabilities (Details) $ in Thousands	Dec. 31, 2019USD ($)
LEASES
2020	$ 1,804
2021	1,874
2022	1,911
2023	1,913
2024	1,796
After 2024	10,615
Total lease payments	19,913
Less: Interest	(8,079)
Total lease liability	$ 11,834

LEASES (Details)

LEASES (Details) $ in Thousands	1 Months Ended		12 Months Ended
	Oct. 31, 2019USD ($)	Oct. 31, 2014USD ($)ft²	Dec. 31, 2019USD ($)lease	Feb. 28, 2019	Jan. 01, 2019USD ($)	Dec. 31, 2018USD ($)	Apr. 30, 2018USD ($)
Operating Lease Liability			$ 11,834
Right of use asset			$ 9,402			$ 0
Restatement Adjustment | ASU 2016-02
Operating Lease Liability					$ 8,100
Right of use asset					$ 9,500
Office Agreement [Member]
Percentage Of Occupancy		45.00%	61.00%
Average Annual Rental Payments	$ 300		$ 1,400
Operating Lease Initial Commitment Period	5 years		15 years
Operating Lease Liability			$ 11,800
Right of use asset			$ 9,400
Number of lease with renewal option | lease			1
lease additional term			2 years
Weighted-average discount rate for operating leases			10.25%	10.25%
Area of Land | ft²		24,000
Weighted-average remaining operating lease term			8 years 4 months 24 days
Line of credit		$ 600
Office Space Lease, Initial Commitment Period		3 years
Additional collateral pledged							$ 600
Operating Lease, Payments, Use			$ 1,500
Minimum [Member] | Office Agreement [Member]
Remaining lease term			4 months
Maximum [Member] | Office Agreement [Member]
Remaining lease term			12 years

INCOME TAXES - Summary of defer

INCOME TAXES - Summary of deferred tax assets and liabilities (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Net operating loss carryforwards	$ 158,177,000	$ 122,678,000
Research and development credit	22,483,000	15,217,000
Noncash compensation	4,680,000	4,394,000
Disallowed interest	710,000	0
Other	661,000	658,000
Deferred tax asset, excluding valuation allowance	186,711,000	142,947,000
Valuation allowance	186,711,000	142,947,000
Net deferred tax assets	$ 0	$ 0

INCOME TAXES - Provision for in

INCOME TAXES - Provision for income taxes (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
INCOME. TAXES.
Loss before income taxes, as reported in the consolidated statements of operations	$ (172,871,000)	$ (173,482,000)	$ (118,476)
Computed "expected" tax benefit	(36,303,000)	(36,431,000)	(40,282)
Increase (decrease) in income taxes resulting from:
Expected benefit from state and local taxes	(2,128,000)	(2,243,000)	(1,106)
Research and development credits	(7,266,000)	(4,726,000)	(3,697)
Other	641,000	639,000	1,563
Stock awards	1,292,000	(473,000)	8,213
Enactment of federal tax reform	0	0	51,768
Change in the balance of the valuation allowance for deferred tax assets	43,764,000	43,234,000	(16,459)
Income Tax Expense (Benefit)	$ 0	$ 0	$ 0

INCOME TAXES (Details)

INCOME TAXES (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Deferred Tax Assets And Liabilities [Line Items]
Less valuation allowance	$ (186,711,000)	$ (142,947,000)
Operating Loss Carryforwards	709,949,000
Additional income tax expense as result of re-measurement of net deferred tax			$ 51,767,584
Research and Development Carryforward	22,483,000
Business Interest Expense Carryforward	3,189,000
Current income tax expense	0
Deferred income tax expense	0
Accrual for interest and penalties related to uncertain tax positions	$ 0
Us Federal Income Tax [Member]
Deferred Tax Assets And Liabilities [Line Items]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	21.00%	34.00%

LICENSE AGREEMENTS (Details)

LICENSE AGREEMENTS (Details)	Dec. 22, 2019shares	Mar. 01, 2019shares	Sep. 22, 2014USD ($)itemshares	Jul. 31, 2019USD ($)	Jun. 30, 2019USD ($)	Apr. 30, 2018USD ($)	Mar. 31, 2017shares	May 31, 2016USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2012USD ($)	Nov. 30, 2012USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
License revenue												$ 152,000	$ 152,000	$ 152,000
Shares issued | shares	5,434,783	4,100,000					769,230
Income taxes												0	0	$ 0
Collaboration Agreement [Member]
Upfront Fee					$ 1,000,000				$ 1,000,000
Manufacturing expense												4,100,000	600,000
JBET Agreement [Member]
Upfront Fee												1,000,000
Income taxes												177,000,000
TGR1202 (Umbralisib) [Member]
Upfront Fee			$ 4,000,000
Additional payments on achievement of certain milestones			$ 175,000,000
Shares issued | shares			371,530
Number of oncology indications | item			2
Number of non oncology indications | item			1
TG-1101 [Member]
Upfront Fee								$ 5,000,000		$ 2,000,000
Term after first commercial sale										15 years
Deferred Revenue												900,000	1,100,000
Deferred Revenue, Current												152,000	$ 152,000
Income taxes										$ 300,000
TG-1701 [Member]
Upfront Fee				$ 100,000		$ 1,000,000						350,000,000
TG-1801 [Member]
Upfront Fee												$ 3,000,000
Additional payments on achievement of certain milestones											$ 185,000,000

RELATED PARTY TRANSACTIONS (Det

RELATED PARTY TRANSACTIONS (Details) $ / shares in Units, $ in Thousands	Dec. 22, 2019shares	Mar. 01, 2019shares	Jun. 30, 2019USD ($)	Mar. 31, 2017USD ($)shares	Jul. 31, 2016USD ($)	Mar. 31, 2015USD ($)	Oct. 31, 2014USD ($)ft²	Dec. 31, 2014	Dec. 31, 2019USD ($)$ / shares	Dec. 31, 2018USD ($)$ / shares	Dec. 31, 2017USD ($)	Jan. 01, 2019USD ($)	Apr. 30, 2018USD ($)	Jul. 28, 2014shares
Related Party Transaction [Line Items]
Common stock, par value (in dollars per share) | $ / shares									$ 0.001	$ 0.001
Shares issued | shares	5,434,783	4,100,000		769,230
Warrants to purchase | shares														1
Other research and development									$ 148,269	$ 149,793	$ 96,886
Operating Lease Liability									11,834
Right of use asset									$ 9,402	0
Collaboration Agreement [Member]
Related Party Transaction [Line Items]
Upfront Fee			$ 1,000			$ 1,000
Office Agreement [Member]
Related Party Transaction [Line Items]
Area of leases office space | ft²							24,000
Initial commitment period for office lease space							3 years
Upfront licensing fee paid					$ 1,000
Expenses incurred				$ 200
Percentage Of Occupancy							45.00%	45.00%	61.00%
Average Annual Rental Payments							$ 1,100
Operating Lease Initial Commitment Period							15 years
Long-term Line of Credit							$ 600
Additional collateral pledged													$ 600
Upfront Fee									$ 4,100	600
Operating Lease Liability												$ 9,300
Right of use asset												$ 7,700
Shared Services Agreement [Member]
Related Party Transaction [Line Items]
Costs and Expenses, Related Party									$ 900	$ 1,600	$ 1,200

COMMITMENTS AND CONTINGENCIES -

COMMITMENTS AND CONTINGENCIES - Contractual obligations (Details) $ in Thousands	Dec. 31, 2019USD ($)
Payment due by period, Contractual obligations, Less than 1 year	$ 49,499
Payment due by period, Contractual obligations, 1-3 years	33,785
Payment due by period, Contractual obligations, 3-5 years	3,709
Payment due by period, Contractual obligations, More than 5 years	10,615
Payment due by period, Contractual obligations, Total	97,608
Operating Leases [Member]
Payment due by period, Contractual obligations, Less than 1 year	2,331
Payment due by period, Contractual obligations, 1-3 years	3,785
Payment due by period, Contractual obligations, 3-5 years	3,709
Payment due by period, Contractual obligations, More than 5 years	10,615
Payment due by period, Contractual obligations, Total	20,440
Long-term debt [Member]
Payment due by period, Contractual obligations, Less than 1 year	0
Payment due by period, Contractual obligations, 1-3 years	30,000
Payment due by period, Contractual obligations, 3-5 years	0
Payment due by period, Contractual obligations, More than 5 years	0
Payment due by period, Contractual obligations, Total	30,000
Contract Manufacturer [Member]
Payment due by period, Contractual obligations, Less than 1 year	47,168
Payment due by period, Contractual obligations, 1-3 years	0
Payment due by period, Contractual obligations, 3-5 years	0
Payment due by period, Contractual obligations, More than 5 years	0
Payment due by period, Contractual obligations, Total	$ 47,168

COMMITMENTS AND CONTINGENCIES_2

COMMITMENTS AND CONTINGENCIES (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Leases, Rent Expense, Net, Total	$ 2,700	$ 1,400	$ 1,400
Contractual obligation	97,608
Operating Leases [Member]
Contractual obligation	$ 20,440

QUARTERLY FINANCIAL INFORMATI_3

QUARTERLY FINANCIAL INFORMATION (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Table Text Block Supplement [Abstract]
License revenue	$ 38	$ 38	$ 38	$ 38	$ 38	$ 38	$ 38	$ 38
Total costs and expenses	37,998	60,899	35,582	34,727	54,188	34,366	44,383	41,615	$ 169,207	$ 174,552	$ 118,864
Net loss	$ (39,571)	$ (61,930)	$ (36,213)	$ (35,156)	$ (53,860)	$ (33,951)	$ (44,142)	$ (41,529)
Basic and diluted net loss per common share	$ (0.44)	$ (0.69)	$ (0.42)	$ (0.43)	$ (0.68)	$ (0.43)	$ (0.59)	$ (0.59)	$ (1.96)	$ (2.30)	$ (1.91)