Oncternal Therapeutics (ONCT) 10-K 18 Mar 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2018	Mar. 12, 2019	Jun. 30, 2018
Document and Entity Information
Entity Registrant Name	GTX INC /DE/
Entity Central Index Key	0001260990
Document Type	10-K
Document Period End Date	Dec. 31, 2018
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Public Float			$ 189,830,468
Entity Common Stock, Shares Outstanding		24,051,844
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY

BALANCE SHEETS

BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 28,258	$ 15,816
Short-term Investments	200	28,083
Prepaid expenses and other current assets	2,750	2,178
Total current assets	31,208	46,077
Property and equipment, net	19	51
Intangible assets, net	94	108
Total assets	31,321	46,236
Current liabilities:
Accounts payable	3,279	2,604
Accrued expenses and other current liabilities	1,931	5,371
Total current liabilities	5,210	7,975
Commitments and contingencies
Stockholders' equity:
Common stock, $0.001 par value: 60,000,000 shares authorized at December 31, 2018 and December 31, 2017; 24,051,844 and 21,541,909 shares issued and outstanding at December 31, 2018 and December 31, 2017, respectively	24	22
Additional paid-in capital	626,142	599,876
Accumulated deficit	(600,055)	(561,637)
Total stockholders' equity	26,111	38,261
Total liabilities and stockholders' equity	$ 31,321	$ 46,236

BALANCE SHEETS (Parenthetical)

BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2018	Dec. 31, 2017
BALANCE SHEETS
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	60,000,000	60,000,000
Common stock, shares issued	24,051,844	21,541,909
Common stock, shares outstanding	24,051,844	21,541,909

STATEMENTS OF OPERATIONS

STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Expenses:
Research and development expenses	$ 3,240	$ 7,467	$ 7,962	$ 11,000	$ 6,912	$ 5,914	$ 4,448	$ 4,193	$ 29,669	$ 21,467	$ 17,228
General and administrative expenses	2,346	2,160	2,196	2,688	2,487	2,617	1,997	2,087	9,390	9,188	8,705
Total expenses	5,586	9,627	10,158	13,688	9,399	8,531	6,445	6,280	39,059	30,655	25,933
Loss from operations	(5,586)	(9,627)	(10,158)	(13,688)	(9,399)	(8,531)	(6,445)	(6,280)	(39,059)	(30,655)	(25,933)
Other income, net	171	196	143	131	122	27	40	27	641	216	46
Gain on change in fair value of warrant liability											8,163
Net loss	$ (5,415)	$ (9,431)	$ (10,015)	$ (13,557)	$ (9,277)	$ (8,504)	$ (6,405)	$ (6,253)	$ (38,418)	$ (30,439)	$ (17,724)
Net loss per share:
Basic and Diluted (in dollars per share)	$ (0.23)	$ (0.39)	$ (0.43)	$ (0.62)	$ (0.43)	$ (0.53)	$ (0.40)	$ (0.39)	$ (1.65)	$ (1.75)	$ (1.22)
Weighted average shares outstanding:
Basic and Diluted (in shares)	24,051,844	24,045,992	23,288,691	21,967,805	21,541,909	16,115,835	16,041,923	16,018,342	23,346,231	17,441,280	14,559,541

STATEMENTS OF STOCKHOLDERS' EQU

STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common StockDirect Offering, October 2016	Common StockPrivate Placement, September 2017	Common StockAt-The-Market Equity Offering	Common Stock	Additional Paid-in CapitalDirect Offering, October 2016	Additional Paid-in CapitalPrivate Placement, September 2017	Additional Paid-in CapitalAt-The-Market Equity Offering	Additional Paid-in Capital	Accumulated Deficit	Direct Offering, October 2016	Private Placement, September 2017	At-The-Market Equity Offering	Total
Balance at Dec. 31, 2015				$ 14				$ 515,319	$ (513,474)				$ 1,859
Balance (in shares) at Dec. 31, 2015				14,037,411
Increase (Decrease) in Stockholders' Equity
Proceeds from issue of new stock or shares	$ 2				$ 13,690					$ 13,692
Proceeds from issue of new stock or shares (in shares)	1,728,395
Shares issued under direct offering	1,728,395
Vesting of restricted stock units, net of shares withheld for tax payments								(208)					(208)
Vesting of restricted stock units, net of shares withheld for tax payments (in shares)				154,170
Directors' deferred compensation								132					132
Share-based compensation								2,957					2,957
Warrant liability reclassification								19,186					19,186
Settlement of fractional shares upon reverse stock split								(3)					(3)
Settlement of fractional shares upon reverse stock split (in shares)				(404)
Net loss									(17,724)				(17,724)
Balance at Dec. 31, 2016				$ 16				551,073	(531,198)				19,891
Balance (in shares) at Dec. 31, 2016				15,919,572
Increase (Decrease) in Stockholders' Equity
Proceeds from issue of new stock or shares (in shares)		5,483,320
Issuance of common stock and warrants in private placement, net of offering costs		$ 6				$ 45,642					$ 45,648
Shares issued under direct offering		5,483,320
Vesting of restricted stock units, net of shares withheld for tax payments								(156)					(156)
Vesting of restricted stock units, net of shares withheld for tax payments (in shares)				139,017
Directors' deferred compensation								166					166
Share-based compensation								3,151					3,151
Net loss									(30,439)				(30,439)
Balance at Dec. 31, 2017				$ 22				599,876	(561,637)				$ 38,261
Balance (in shares) at Dec. 31, 2017				21,541,909									21,541,909
Increase (Decrease) in Stockholders' Equity
Issuance of common stock upon exercise of warrants				$ 1				(1)
Issuance of common stock upon exercise of warrants (in shares)				674,579
Exercise of employee stock options								103					$ 103
Exercise of employee stock options (in shares)				6,000
Proceeds from issue of new stock or shares			$ 1				$ 24,473					$ 24,474
Proceeds from issue of new stock or shares (in shares)			1,501,501
Shares issued under direct offering			1,501,501
Vesting of restricted stock units, net of shares withheld for tax payments								(672)					(672)
Vesting of restricted stock units, net of shares withheld for tax payments (in shares)				327,855
Directors' deferred compensation								166					166
Share-based compensation								2,197					2,197
Net loss									(38,418)				(38,418)
Balance at Dec. 31, 2018				$ 24				$ 626,142	$ (600,055)				$ 26,111
Balance (in shares) at Dec. 31, 2018				24,051,844									24,051,844

STATEMENTS OF CASH FLOWS

STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net loss	$ (38,418)	$ (30,439)	$ (17,724)
Adjustments to reconcile net loss to net cash used in operating activities:
Gain on change in fair value of warrant liability			(8,163)
Share-based compensation	2,197	3,151	2,957
Directors' deferred compensation	166	166	132
Depreciation and amortization	46	47	28
Changes in assets and liabilities:
Prepaid expenses and other assets	(572)	251	204
Accounts payable	675	1,384	838
Accrued expenses and other liabilities	(3,440)	1,980	950
Net cash used in operating activities	(39,346)	(23,460)	(20,778)
Cash flows from investing activities:
Purchase of property and equipment		(2)	(90)
Purchase of short-term investments, held to maturity	(44,155)	(39,283)	(35,404)
Proceeds from maturities of short-term investments, held to maturity	72,038	24,159	37,645
Net cash provided by (used in) investing activities	27,883	(15,126)	2,151
Cash flows from financing activities:
Net proceeds from the issuance of common stock and warrants	24,474	45,648	13,692
Tax payments related to shares withheld for vested restricted stock units	(672)	(156)	(208)
Proceeds from exercise of employee stock options	103
Settlement of fractional shares upon reverse stock split			(3)
Net cash provided by financing activities	23,905	45,492	13,481
Net increase (decrease) in cash and cash equivalents	12,442	6,906	(5,146)
Cash and cash equivalents, beginning of period	15,816	8,910	14,056
Cash and cash equivalents, end of period	$ 28,258	$ 15,816	$ 8,910

Business

Business	12 Months Ended
	Dec. 31, 2018
Business
Business	1. Business GTx, Inc. (“GTx” or the “Company”), a Delaware corporation incorporated on September 24, 1997 and headquartered in Memphis, Tennessee, is a biopharmaceutical company dedicated to the discovery, development and commercialization of medicines to treat serious and/or significant unmet medical conditions. In 2015, the Company entered into an exclusive license agreement with the University of Tennessee Research Foundation (“UTRF”) to develop UTRF’s proprietary selective androgen receptor degrader (“SARD”) technology which may have the potential to provide compounds that can degrade or antagonize multiple forms of androgen receptor to treat those patients who do not respond or are resistant to current androgen targeted therapies by inhibiting tumor growth in patients with progressive castration-resistant prostate cancer (“CRPC”). The Company is in the process of completing ongoing mechanistic preclinical studies in order to select the most appropriate SARD compounds to move forward into the additional preclinical studies required to submit an investigational new drug application (“IND”), and potentially advance one of its SARD compounds into a first-in-human clinical trial. The Company had been developing selective androgen receptor modulators (“SARMs”), including enobosarm (GTx-024). Most recently, enobosarm was evaluated in post-menopausal women with stress urinary incontinence (“SUI”) compared to placebo. During the third quarter of 2018, the Company announced that the Phase 2 double-blind, placebo-controlled clinical trial of orally-administered enobosarm (3 mg or 1 mg) in post-menopausal women with SUI (the “ASTRID trial”) did not achieve statistical significance on the primary endpoint for the trial. The Company has completed the ASTRID trial, including its review of the full data sets from the clinical trial, and has determined that there is not a sufficient path forward to warrant additional clinical development of enobosarm to treat SUI. The Company has therefore discontinued further development of enobosarm to treat SUI, including discontinuing the related durability and open-label safety extension studies that the Company initiated before it received topline data from the ASTRID trial. The Company has also discontinued any further development of its SARM program generally. Following the announcement of the ASTRID trial results, the Company’s board of directors commenced a process of evaluating strategic alternatives to maximize stockholder value. To assist with this process, the Company’s board of directors engaged a financial advisory firm to help explore the Company’s available strategic alternatives, including possible mergers and business combinations, a sale of part or all of the Company’s assets, and collaboration and licensing arrangements. On March 6, 2019, the Company and Oncternal Therapeutics Inc. (“Oncternal”) announced the signing of an Agreement and Plan of Merger and Reorganization (the “Merger Agreement”). Upon the terms and subject to the satisfaction of the conditions described in the Merger Agreement, including approval of the transaction by the Company’s stockholders and Oncternal’s stockholders, a wholly-owned subsidiary of the Company will be merged with and into Oncternal (the “Merger”), with Oncternal surviving the Merger as a wholly-owned subsidiary of the Company. See Note 2, Significant Accounting Policies – Subsequent Events, for further discussion regarding the proposed Merger. At December 31, 2018, the Company had cash, cash equivalents and short-term investments of $28,458 compared to $43,899 at December 31, 2017. To conserve its cash resources, the Company has substantially reduced its workforce since November 2018 and has ceased its SARM development activities and all other operations except for day-to-day business operations, completing ongoing mechanistic SARD preclinical studies and those activities necessary to complete the proposed Merger.

Significant Accounting Policies

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Significant Accounting Policies
Significant Accounting Policies	2. Significant Accounting Policies Basis of Presentation The accompanying financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”). Additionally, GTx operates in one business segment. Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual amounts and results could differ from those estimates. Cash and Cash Equivalents The Company considers highly liquid investments with initial maturities of three months or less to be cash equivalents. Short-term Investments At December 31, 2018 and 2017, short-term investments consisted of Federal Deposit Insurance Corporation (“FDIC”) insured certificates of deposit with original maturities of greater than three months and less than one year. Property and Equipment Property and equipment is stated at cost. Amortization of leasehold improvements is recognized over the shorter of the estimated useful life of the leasehold improvement or the lease term. Depreciation is computed using the straight-line method over the estimated useful lives as follows: Office equipment 3 to 5 years Leasehold improvements 3 to 7 years Furniture and fixtures 5 years Computer equipment and software 3 years Warrant Liability In November 2014, the Company issued warrants to purchase 6,430,948 shares of its common stock. The Company classified these warrants as a liability on its balance sheet since the warrants contained certain terms that could have required the Company (or its successor) to purchase the warrants for cash in an amount equal to the value (as calculated utilizing a contractually-agreed Black-Scholes-Merton option pricing valuation model ("Black-Scholes Model")) of the unexercised portion of the warrants in connection with certain change of control transactions occurring on or prior to December 31, 2016, with such cash payment capped at an amount equal to $1.25 per unexercised share underlying each warrant. As a result of the provision of the warrants requiring cash settlement upon certain change of control transactions, the Company was required to account for these warrants as a liability at fair value and the estimated warrant liability was required to be revalued at each balance sheet date until the earlier of the exercise of the warrants, the modification to remove the provision that could require cash settlement upon certain change of control transactions or the expiration of such provision on December 31, 2016. Effective March 25, 2016, each of the warrants was amended by agreement of the warrant holders to remove the provision that could require cash settlement upon certain change of control transactions. These warrants were no longer accounted for as a liability as of March 31, 2016. The Company recorded a non-cash reclassification of the warrant fair value to stockholders' equity based on the warrants' fair value as of the March 25, 2016 modification date, with no further adjustments to the fair value of these warrants being required. Fair Value of Financial Instruments and Warrant Liability The carrying amounts of the Company’s financial instruments (which include cash, cash equivalents, short-term investments, and accounts payable) and its prior warrant liability approximate their fair values. The fair value of the warrant liability was estimated using the Black-Scholes-Merton Model. See Note 6, Stockholders' Equity, for additional disclosure on the valuation methodology and significant assumptions. The Company’s financial assets and liabilities are classified within a three-level fair value hierarchy that prioritizes the inputs used to measure fair value, which is defined as follows: Level 1 – Quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date Level 2 – Inputs other than quoted prices in active markets that are observable for the asset or liability, either directly or indirectly Level 3 – Inputs that are unobservable for the asset or liability As the Company has the positive intent and ability to hold its certificates of deposit classified as short-term investments until maturity, these investments have been classified as held to maturity investments and are stated at cost, which approximates fair value. The Company considers these to be Level 2 investments as the fair values of these investments are determined using third-party pricing sources, which generally utilize observable inputs, such as interest rates and maturities of similar assets. Concentration of Risk Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash and cash equivalents and short-term investments. The Company has established guidelines relating to diversification and maturities of its cash equivalents and short-term investments which are designed to manage risk. The Company’s cash and cash equivalents consist of bank deposits, certificates of deposit, and money market mutual funds. Bank deposits may at times be in excess of FDIC insurance limits. The Company’s short-term investments consist of FDIC insured certificates of deposit with original maturities of greater than three months and less than one year. Research and Development Expenses Research and development expenses include, but are not limited to, the Company’s expenses for personnel, supplies, and facilities associated with research activities, screening and identification of product candidates, formulation and synthesis activities, manufacturing, preclinical studies, toxicology studies, clinical trials, regulatory and medical affairs activities, quality assurance activities and license fees. The Company expenses these costs in the period in which they are incurred. The Company estimates its liabilities for research and development expenses in order to match the recognition of expenses to the period in which the actual services are received. As such, accrued liabilities related to third party research and development activities are recognized based upon the Company’s estimate of services received and degree of completion of the services in accordance with the specific third party contract. Patent Costs The Company expenses patent costs, including legal expenses, in the period in which they are incurred. Patent expenses are included in general and administrative expenses in the Company’s statements of operations. Income Taxes The Company accounts for deferred taxes by recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements or tax returns. Under this method, deferred tax assets and liabilities are determined based on the difference between the financial statement and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. A valuation allowance is provided when it is more likely than not that some portion or all of the deferred tax assets will not be realized. Accordingly, at December 31, 2018 and December 31, 2017, net of the valuation allowance, the net deferred tax assets were reduced to zero. See Note 8, Income Taxes , for further discussion. Share-Based Compensation The Company has stock option and equity incentive plans that provide for the purchase or acquisition of the Company’s common stock by certain of the Company’s employees and non-employees. The Company recognizes compensation expense for its share-based payments based on the fair value of the awards over the period during which an employee or non-employee is required to provide service in exchange for the award. See Note 3, Share-Based Compensation , for further discussion. Other Income (Expense), Net Other income (expense), net consists of interest earned on the Company’s cash, cash equivalents and short-term investments, foreign currency transaction gains and losses, and other non-operating income or expense. Basic and Diluted Net Loss Per Share Basic and diluted net income (loss) per share attributable to common stockholders is calculated based on the weighted average number of common shares outstanding during the period. Diluted net income (loss) per share gives effect to the dilutive potential of common stock consisting of stock options, unvested RSUs and common stock warrants. Weighted average potential shares of common stock of 11,191,431, 9,438,236, and 8,162,347 were excluded from the calculation of diluted net loss per share for the years ended December 31, 2018, 2017 and 2016, respectively, as inclusion of the potential shares would have had an anti-dilutive effect on the net loss per share for the periods. At December 31, 2018, the Company had 24,051,844 shares of common stock outstanding. Comprehensive Loss For all periods presented, there were no differences between net loss and comprehensive loss. Recent Accounting Pronouncements In February 2016, the Financial Accounting Standards Board issued Accounting Standard Update (“ASU”) 2016-02, Leases (Topic 842). This ASU requires that lessees recognize assets and liabilities on the balance sheet for the present value of the rights and obligations created by all leases with terms of more than 12 months. The ASU also will require disclosures designed to give financial statement users information on the amount, timing, and uncertainty of cash flows arising from leases. This new guidance will be effective for the Company as of January 1, 2019. The Company does not expect the adoption of the standard update to have a significant impact on its financial position or results of operations. Subsequent Events The Company has evaluated all events or transactions that occurred after December 31, 2018 up through the date the financial statements were issued. Other than as set forth below, there were no material recognizable or nonrecognizable subsequent events during the period evaluated. Merger Agreement with Oncternal and Related Matters Merger Agreement On March 6, 2019, the Company entered into the Merger Agreement with Oncternal and Grizzly Merger Sub, Inc., a wholly-owned subsidiary of the Company ("Merger Sub"). Upon the terms and subject to the satisfaction of the conditions described in the Merger Agreement, including approval of the transaction by the Company's stockholders and Oncternal's stockholders, Merger Sub will be merged with and into Oncternal, with Oncternal surviving the Merger as a wholly-owned subsidiary of the Company. Subject to the terms and conditions of the Merger Agreement, at the effective time of the Merger (the "Effective Time"): (i) each share of Oncternal common stock outstanding immediately prior to the Effective Time (excluding shares held by the Company, Merger Sub or Oncternal and dissenting shares) will be converted solely into the right to receive a number of shares of the Company's common stock (the "Shares") equal to the exchange ratio described below, (ii) each outstanding Oncternal stock option will be assumed by the Company, and (iii) each outstanding Oncternal warrant will be assumed by the Company. Under the exchange ratio formula in the Merger Agreement, the former Oncternal stockholders immediately before the Merger are expected to own approximately 75% of the outstanding capital stock of the Company, and the stockholders of the Company immediately before the Merger are expected to own approximately 25% of the outstanding capital stock of the Company, subject to certain assumptions. The exchange ratio formula excludes Oncternal's outstanding stock options and warrants and the Company's outstanding stock options and warrants. Under certain circumstances further described in the Merger Agreement, the ownership percentages may be adjusted upward or downward based on cash levels of the respective companies at the closing of the Merger (the "Closing"). The Merger Agreement contains customary representations, warranties and covenants made by the Company and Oncternal, including covenants relating to obtaining the requisite approvals of the stockholders of the Company and Oncternal, indemnification of directors and officers, the Company’s and Oncternal’s conduct of their respective businesses between the date of signing of the Merger Agreement and the Closing. The Closing is subject to satisfaction or waiver of certain conditions included in the Merger Agreement. Following the Closing, Oncternal’s Chief Executive Officer, Chief Financial Officer, and Chief Operating Officer will serve in these positions for the Company. Additionally, following the Closing, the Company’s board of directors will consist of nine directors, including two current GTx board members. The Merger Agreement also includes termination provisions for both the Company and Oncternal. In connection with a termination of the Merger Agreement under specified circumstances, either party may be required to pay the other party a termination fee ranging between $500 to $2,000. Contingent Value Rights Agreement At the Effective Time, the Company will enter into a Contingent Value Rights Agreement (the "CVR Agreement"). Pursuant to the CVR Agreement, for each share of the Company's common stock held, the Company's stockholders of record as of immediately prior to the Effective Time will receive one contingent value right ("CVR") entitling such holders to receive in the aggregate 50% of any net proceeds received during the 15-year period after closing from the grant, sale or transfer of rights to the Company's SARD or SARM technology that occurs during the 10-year period after the Closing (or in the 11th year if based on a term sheet approved during the initial 10-year period) and, if applicable, to receive royalties on the sale of any SARD products by the combined company during the 15-year period after Closing. The CVR Agreement will be effective prior to the Closing and will continue in effect until the payment of all amounts payable thereunder, unless terminated upon termination of the Merger Agreement. Workforce Reduction In the first quarter of 2019, due to the entry into the Merger Agreement with Oncternal, the Company's board of directors committed to reducing its workforce by seven employees. All employees affected by the workforce reduction will be eligible to receive, among other things, specified severance payments based on the applicable employee's level and years of service with the Company and the continuation of group health insurance coverage. In addition, the affected employees will also be eligible for full vesting acceleration of their outstanding stock options as well as an extension of the post-termination exercise period for their outstanding stock options. As a result of the workforce reduction and prior termination of three employees earlier in the first quarter of 2019, the Company estimates that it will incur total severance-related charges for these employees of approximately $1,000 in the first quarter of 2019 and up to an additional $500 contingent upon the closing of the Merger. The Company does not expect to record a non-cash charge related to the modification of outstanding stock options in connection with the workforce reduction. Termination of Directors' Deferred Compensation Plan Prior to the Effective Time (but in no event more than 30 days prior to the Effective Time), the Company’s board of directors will take all actions necessary to terminate and liquidate the Company’s 2018 Amended and Restated Directors’ Deferred Compensation Plan (the “Directors’ Deferred Compensation Plan”) and all rights or other deferrals thereunder effective immediately prior to the Effective Time, subject to the consummation of the Merger. Any future board compensation under the Directors’ Deferred Compensation Plan on or after January 3, 2019 shall be settled only in cash.

Share-Based Compensation

Share-Based Compensation	12 Months Ended
	Dec. 31, 2018
Share-Based Compensation
Share-Based Compensation	3. Share-Based Compensation Share-based payments include stock option and RSU grants under the Company’s stock option and equity incentive plans and deferred compensation arrangements for the Company’s non-employee directors. The Company has granted to employees and non-employees options to purchase common stock under various plans at prices equal to the fair market value of its common stock on the dates the options are granted as determined in accordance with the terms of the applicable plan. The options have a term of ten years from the grant date and generally vest over three years from the grant date for director and non-employee options and over periods of up to five years from the grant date for employee options. Under the terms of the Company’s stock option and equity incentive plans, employees generally have three months after the employment relationship ends to exercise all vested options except in the case of voluntary retirement, disability or death, where post-termination exercise periods are generally longer. The Company issues new shares of common stock upon the exercise of options. The Company estimates the fair value of stock option awards as of the date of the grant by applying the Black-Scholes Model. The application of this valuation model involves assumptions that are judgmental and highly sensitive in the determination of compensation expense. The fair value of each stock option is amortized into compensation expense on a straight-line basis between the grant date for the award and each vesting date. During 2017, the Company adopted the Financial Accounting Standards Board Accounting Standards Update 2016-09, Improvements to Employee Share Based Payment Accounting . This guidance addresses the income tax effects of stock-based payments and eliminates the windfall pool concept, as all of the tax effects related to stock-based payments are now being recorded at settlement (or expiration) through the income statement. The new guidance also permits entities to make an accounting policy election for the impact of forfeitures on the recognition of expense for stock-based payment awards, allowing for forfeitures to be estimated or recognized when they occur. The Company elected to prospectively adopt the policy that forfeitures be recorded when they occur and prior periods have not been adjusted. The adoption of this guidance did not have a material impact on the Company’s financial position or results of operations. Additionally, the Company periodically grants RSUs to its employees. The Company estimates the fair value of RSUs using the closing price of its common stock on the grant date. The fair value of the RSUs is amortized on a straight-line basis over the requisite service period of the awards. All RSUs were fully vested at December 31, 2018. The following table summarizes share-based compensation expense included within the statements of operations for each of the three years in the period ended December 31, 2018: Years Ended December 31, 2018 2017 2016 Research and development expenses $ 807 $ 1,171 $ 1,260 General and administrative expenses 1,556 2,146 1,829 Total share-based compensation $ 2,363 $ 3,317 $ 3,089 Share-based compensation expense recorded in the statement of operations as general and administrative expense for the years ended December 31, 2018, 2017 and 2016 included share-based compensation expense related to deferred compensation arrangements for the Company’s non-employee directors of $166, $166 and $132, respectively. See Note 9, Directors’ Deferred Compensation Plan , for further discussion of deferred compensation arrangements for the Company’s non-employee directors. For the years ended December 31, 2018, 2017 and 2016, the weighted average grant date fair value per share of stock options granted was $10.36, $3.80 and $5.45, respectively. The key assumptions used in determining the grant date fair value of options granted in 2018, 2017 and 2016, and a summary of the methodology applied to develop each assumption is as follows: Years Ended December 31, 2018 2017 2016 Expected price volatility 93.1 % 88.6 % 91.3 % Risk-free interest rate 2.4 % 2.2 % 2.0 % Weighted average expected life in years years 6.9 years 6.9 years Dividend yield 0 % 0 % 0 % Expected Price Volatility - This is a measure of the amount by which a price has fluctuated or is expected to fluctuate. The Company based its determination of expected volatility on its historical stock price volatility. An increase in the expected price volatility will increase compensation expense. Risk-Free Interest Rate - This is determined using U.S. Treasury rates where the term is consistent with the expected life of the stock options. An increase in the risk-free interest rate will increase compensation expense. Expected Life - This is the period of time over which the options granted are expected to remain outstanding and is determined by calculating the average of the vesting term and the contractual term of the options. The Company has utilized this method due to the lack of historical option exercise information related to the Company’s stock option and equity incentive plans. Options granted have a maximum term of ten years. An increase in the expected life will increase compensation expense. Dividend Yield - The Company has not made any dividend payments nor does it have plans to pay dividends in the foreseeable future. An increase in the dividend yield will decrease compensation expense. The following is a summary of stock option transactions for all of the Company’s stock option and equity incentive plans for the three year period ended December 31, 2018: Weighted Average Number of Exercise Price Shares Per Share Options outstanding at January 1, 2016 798,309 $ 38.80 Options granted 363,500 6.94 Options forfeited or expired (71,829) 54.65 Options exercised — — Options outstanding at December 31, 2016 1,089,980 27.13 Options granted 977,350 4.97 Options forfeited or expired (166,834) 48.71 Options exercised — — Options outstanding at December 31, 2017 1,900,496 13.84 Options granted 472,000 13.32 Options forfeited or expired (31,049) 168.76 Options exercised (6,000) 17.23 Options outstanding and vested or expected to vest at December 31, 2018 2,335,447 $ 11.67 The following table summarizes information about stock options outstanding at December 31, 2018: Options Outstanding Options Exercisable Weighted Average Weighted Weighted Remaining Average Average Number Contractual Exercise Number Exercise Exercise Price Outstanding Life (years) Price Exercisable Price $4.29 - $4.29 56,250 $ 4.29 18,750 $ 4.29 $4.71 - $4.71 825,000 4.71 22,500 4.71 $4.77 - $12.71 826,800 9.97 134,404 8.25 $12.95 - $108.90 627,397 23.71 508,691 25.59 2,335,447 11.67 684,345 20.91 At December 31, 2018, the aggregate intrinsic value of all outstanding options was zero with a weighted average remaining contractual term of 6.88 years. Of the Company’s outstanding options, 684,345 options were exercisable and had a weighted average remaining contractual term of 4.05 years and no aggregate intrinsic value. Additionally, the Company's vested and expected to vest options had a weighted average remaining contractual term of 6.88 years and no aggregate intrinsic value. Options to purchase 6,000 shares were exercised during the years ended December 31, 2018. The total intrinsic value of options exercised during the years ended December 31, 2018 was $39. At December 31, 2018, the total compensation cost related to non-vested options not yet recognized was $7,697, with a weighted average expense recognition period of 2.95 years. Shares available for future issuance under the Company’s stock option and equity incentive plans were 1,167,162 at December 31, 2018. On January 1, 2019, shares available for future issuance under the 2013 equity incentive plan and the 2013 non-employee director equity incentive plan increased by an aggregate of 1,012,074 shares in accordance with the automatic increase provisions of such plans. The following is a summary of the RSU transactions for all of the Company’s equity incentive plans for the three year period ended December 31, 2018: Number of Shares Nonvested RSUs outstanding at January 1, 2016 820,000 RSUs granted 11,000 RSUs vested (184,001) RSUs forfeited (62,000) Nonvested RSUs outstanding at December 31, 2016 584,999 RSUs granted — RSUs vested (168,499) RSUs forfeited (36,000) Nonvested RSUs outstanding at December 31, 2017 380,500 RSUs granted — RSUs vested (380,500) RSUs forfeited — Nonvested RSUs outstanding at December 31, 2018 — The number of RSUs vested during 2018, 2017, and 2016 included 52,645, 29,482, and 29,829 shares, respectively, that were withheld on behalf of the Company’s employees to satisfy the statutory tax withholding requirements.

Property and Equipment, Net

Property and Equipment, Net	12 Months Ended
	Dec. 31, 2018
Property and Equipment, Net
Property and Equipment, Net	4. Property and Equipment, Net Property and equipment, net consisted of the following: December 31, 2018 2017 Computer equipment and software $ 1,225 $ 1,299 Furniture and fixtures 853 853 Leasehold improvements 355 355 Office equipment 211 211 2,644 2,718 Less: accumulated depreciation (2,625) (2,667) $ 19 $ 51 Depreciation and amortization expense for the years ended December 31, 2018, 2017 and 2016 was $32, $32, and $14, respectively. Of these amounts, $1, $2 and $2, respectively, were included in research and development expenses in the statements of operations.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	12 Months Ended
	Dec. 31, 2018
Accrued Expenses and Other Current Liabilities
Accrued Expenses and Other Current Liabilities	5. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of the following: December 31, 2018 2017 Clinical trials $ 1,492 $ 4,742 General and administrative 101 314 Research and development 272 312 Employee compensation 66 3 $ 1,931 $ 5,371

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2018
Stockholders' Equity
Stockholders' Equity	6. Stockholders’ Equity Authorized Capital On December 5, 2016, the Company filed a Certificate of Amendment to the Company’s Restated Certificate of Incorporation with the Secretary of State of the State of Delaware to effect a one-for-ten reverse stock split of its outstanding common stock and to effect a reduction in the number of authorized shares of common stock from 400,000,000 to 60,000,000 shares. The Company’s certificate of incorporation currently authorizes the Company to issue 60,000,000 shares of common stock, $0.001 par value per share, and 5,000,000 shares of preferred stock, $0.001 par value per share. Common Stock On February 9, 2018, the Company entered into an At-the-Market Equity Offering Sales Agreement (the “ATM Sales Agreement”) with Stifel, Nicolaus & Company, Incorporated, as sales agent (“Stifel”), pursuant to which the Company may offer and sell, from time to time, through Stifel, shares of the Company’s common stock, having an aggregate offering price of up to $50,000. On May 16, 2018, the Company sold 1,501,501 shares of common stock under the ATM Sales Agreement for net proceeds of $24,474. As of December 31, 2018, the Company had approximately $25,000 of common stock remaining available to be sold under the ATM Sales Agreement. On September 29, 2017, the Company completed a private placement of units consisting of an aggregate of 5,483,320 shares of common stock and warrants to purchase an aggregate of 3,289,988 shares of its common stock for net proceeds of $45,648, after deducting placement agent fees and other offering expenses. The purchasers in the private placement consisted solely of accredited investors that included certain institutional and existing stockholders, including a member of the Company’s board of directors. The warrants, which have five year terms expiring on September 29, 2022, are immediately exercisable and have a per share exercise price of $9.02. The Company assessed whether the warrants require accounting as derivatives. The Company determined that the warrants were indexed to the Company’s own stock. As such, the Company has concluded the warrants meet the scope exception for determining whether the instruments require accounting as derivatives and are classified in stockholders’ equity. The fair value of the warrants was estimated at $21,069 using the Black-Scholes Model with the following assumptions: expected volatility of 97%, risk free interest rate of 1.92%, expected life of five years and no dividends. The net proceeds from the private placement were allocated to the common stock and warrants based upon their relative fair values. On October 14, 2016, the Company completed a registered direct offering of its common stock. Under the terms of the offering, the Company sold 1,728,395 shares of its common stock for net proceeds of $13,692, after deducting offering expenses. On November 14, 2014, the Company completed a private placement of units consisting of an aggregate of 6,431,111 shares of common stock and warrants to purchase an aggregate of 6,430,948 shares of its common stock for net proceeds of $42,814, after deducting offering expenses. The net proceeds from the private placement were allocated to the common stock and warrants based upon the fair value method. Similarly, the offering expenses were allocated between the common stock and warrants with the portion allocated to common stock offset against the proceeds allocated to stockholders’ equity, whereas the portion allocated to the warrants was expensed immediately. The warrants have a per share exercise price of $8.50, became exercisable on May 6, 2015 and will continue to be exercisable for four years thereafter. Prior to May 6, 2015, each warrant was subject to net cash settlement if, at the time of any exercise, there was then an insufficient number of authorized and reserved shares of common stock to effect a share settlement of the warrant. Under the terms of the warrants, as of May 6, 2015, the net cash settlement feature of the warrants automatically became inoperative; accordingly, the warrants are exercisable only for shares of the Company's common stock. The warrants, however, also contained certain terms that could have required the Company (or its successor) to purchase the warrants for cash in an amount equal to the value (as calculated utilizing a contractually-agreed Black-Scholes Model) of the unexercised portion of the warrants in connection with certain change of control transactions occurring on or prior to December 31, 2016, with the cash payment capped at an amount equal to $1.25 per unexercised share underlying each warrant. Due to the provision of the warrants that could have required cash settlement upon certain change of control transactions, the Company was required to account for these warrants as a liability at fair value using the Black-Scholes Model and the estimated warrant liability was required to be revalued at each balance sheet date until the earlier of the exercise of the warrants, the modification to remove the provision that could require cash settlement upon certain change of control transactions or the expiration of such provision on December 31, 2016. Effective March 25, 2016, each of the warrants was amended by agreement of the warrant holders to remove the provision that could require cash settlement upon certain change of control transactions. These warrants were no longer accounted for as a liability at March 31, 2016. The Company recorded a non-cash reclassification of the warrant fair value to stockholders' equity based on the warrants' fair value as of the March 25, 2016 modification date, with no further adjustments to the fair value of these warrants being required. In March 2018, certain holders of warrants issued in November 2014 exercised warrants covering 1,111,082 shares of common stock in a cashless exercise for which the Company issued an aggregate of 674,579 shares of common stock upon exercise. Each of these completed offerings included certain existing GTx stockholders and/or certain members of the GTx management team and/or board of directors.

License Agreements

License Agreements	12 Months Ended
	Dec. 31, 2018
License Agreements
License Agreements	7. License Agreements University of Tennessee Research Foundation License Agreements The Company and the University of Tennessee Research Foundation (“UTRF”) are parties to a consolidated, amended and restated license agreement (the “SARM License Agreement”) pursuant to which the Company has been granted exclusive worldwide rights in all existing SARM technologies owned or controlled by UTRF, including all improvements thereto, and exclusive rights to future SARM technology that may be developed by certain scientists at the University of Tennessee or subsequently licensed to UTRF under certain existing inter-institutional agreements with The Ohio State University. Under the SARM License Agreement, the Company is obligated to pay UTRF annual license maintenance fees, low single-digit royalties on net sales of products and mid single-digit royalties on sublicense revenues. In accordance with the terms of the SARM License Agreement that the Company entered into with UTRF in July 2007, the Company paid a one-time up-front fee of $290, which was recorded as an intangible asset by the Company. This intangible asset, net at December 31, 2018 and 2017 was $94 and $108, respectively. The Company and UTRF also entered into a license agreement in March 2015 pursuant to which the Company was granted exclusive worldwide rights in all existing SARD technologies owned or controlled by UTRF, including all improvements thereto (the "SARD License Agreement"). Under the SARD License Agreement, the Company is obligated to employ active, diligent efforts to conduct preclinical research and development activities for the SARD program to advance one or more lead compounds into clinical development. The Company is also obligated to pay UTRF annual license maintenance fees, low single-digit royalties on net sales of products and additional royalties on sublicense revenues, depending on the state of development of a clinical product candidate at the time it is sublicensed.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Taxes
Income Taxes	8. Income Taxes The Tax Cuts and Jobs Act ("Tax Reform Act") was enacted on December 22, 2017. The Tax Reform Act significantly revised the U.S. corporate income tax regime by, among other things, lowering the U.S. corporate tax rate from 35% to 21% effective January 1, 2018. On December 22, 2017, the SEC staff issued Staff Accounting Bulletin No. 118 (“SAB 118”) to address the application of U.S. GAAP in situations when a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the Tax Reform Act. The Company recognized the provisional tax impacts related to the revaluation of deferred tax assets and liabilities and included these amounts in its financial statements for the year ended December 31, 2017. During 2018 the Company completed the accounting under the Tax Reform Act as allowed under SAB 118 to revalue its deferred tax assets and liabilities which resulted in no change to the amounts previously recorded by the Company for year ended December 31, 2017. Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. The principal components of the Company’s net deferred income tax assets and liabilities consisted of the following: December 31, 2018 2017 Deferred income tax assets: Net federal and state operating loss carryforwards $ 120,555 $ 110,145 Research and development credits 16,383 14,757 Share-based compensation 3,130 3,994 Depreciation and amortization 17 21 Total deferred tax assets 140,085 128,917 Deferred income tax liabilities: Other 461 92 Total deferred tax liabilities 461 92 Net deferred tax assets 139,624 128,825 Valuation allowance (139,624) (128,825) $ — $ — Realization of deferred income tax assets is dependent upon future earnings, if any, the timing and amount of which are uncertain. Accordingly, due to the Company’s history of net operating losses, the net deferred tax assets have been fully offset by a valuation allowance. The valuation allowance increased by $10,799 in 2018, decreased by $47,132 in 2017 and increased in 2016 by $9,347. The valuation allowance decrease in 2017 was due primarily to the passage of the Tax Reform Act and the reduction in the valuation of the Company's net deferred tax assets as a result of the lowering of the corporate tax rate from 35% to 21% effective January 1, 2018. At December 31, 2018, the Company had net federal operating loss carryforwards of approximately $472,054. The federal operating loss carryforwards originating prior to 2018 will expire from 2019 to 2037 if not utilized. The Company had state operating loss carryforwards of approximately $411,396, which expire from 2019 to 2038 if not utilized. The Company also had research and development credits at December 31, 2018 of approximately $16,383, which expire from 2020 to 2038 if not utilized. The Company will recognize the impact of a tax position in the financial statements if that position is more likely than not of being sustained on audit based on the technical merits of the position. As of December 31, 2018, the Company had no unrecognized tax benefits. Utilization of the Company’s net operating loss carryforwards may be subject to a substantial annual limitation due to ownership change limitations provided by Section 382 of the Internal Revenue Code of 1986, as amended, and similar state provisions. The annual limitations may result in the expiration of net operating loss carryforwards before utilization. The Company completed a study of its net operating losses through December 31, 2016 to determine whether such amounts are likely to be limited by Section 382. As a result of this study and its analysis of subsequent ownership changes, the Company does not currently believe any Section 382 limitation exists through December 31, 2018 though the Company has not yet conducted an in-depth analysis since the last study. However, any future ownership changes under Section 382 may limit the Company’s ability to fully utilize these tax benefits. The Company has not yet conducted an in-depth study of its research and development credits, although the Company periodically reviews assumptions used in its calculations to reflect its best estimate of expected credit. An in-depth study may result in an increase or decrease to the Company’s research and development credits and until such study is conducted of the Company’s research and development credits, no amounts are being presented as an uncertain tax position. The Company’s net deferred income tax assets have been fully offset by a valuation allowance. Therefore, future changes to the Company’s unrecognized tax benefits would be offset by an adjustment to the valuation allowance and there would be no impact on the Company’s balance sheet, statement of operations, or cash flows. The Company does not expect its unrecognized tax benefits to change significantly over the next 12 months. The Company is currently open to audit under the statute of limitations by the Internal Revenue Service and the appropriate state income taxing authorities for all years due to the net loss carryforwards from those years. The Company is currently not under examination by the Internal Revenue Service or any other taxing authorities. The Company has not recorded any interest and penalties on any unrecognized tax benefits since its inception.

Directors' Deferred Compensatio

Directors' Deferred Compensation Plan	12 Months Ended
	Dec. 31, 2018
Directors' Deferred Compensation Plan
Directors' Deferred Compensation Plan	9. Directors’ Deferred Compensation Plan Non-employee directors may defer all or a portion of their fees under the Company’s Directors’ Deferred Compensation Plan until termination of their status as directors. Deferrals can be made into a cash account, a stock account, or a combination of both. Stock accounts will be paid out in the form of Company common stock, except that any fractional shares will be paid out in cash valued at the then current market price of the Company’s common stock. Cash accounts and stock accounts under the Directors’ Deferred Compensation Plan are credited with interest or the value of any cash and stock dividends, respectively. Non-employee directors are fully vested in any amounts that they elect to defer under the Directors’ Deferred Compensation Plan. For the years ended December 31, 2018, 2017 and 2016, the Company incurred non-employee director fee expense of $291, $291 and $257, respectively, of which $166, $166 and $132 was deferred into stock accounts and will be paid in common stock following separation from service as a director. At December 31, 2018, 122,725 shares of the Company’s common stock had been credited to individual director stock accounts under the Directors’ Deferred Compensation Plan, and no amounts had been credited to individual director cash accounts under the Directors’ Deferred Compensation Plan.

401(k) Plan

401(k) Plan	12 Months Ended
	Dec. 31, 2018
401(k) Plan
401(k) Plan	10. 401(k) Plan The Company sponsors a 401(k) retirement savings plan that is available to all eligible employees. The plan is intended to qualify under Section 401(k) of the Internal Revenue Code of 1986, as amended. The plan provides that each participant may contribute up to a statutory limit of their pre-tax compensation which was $18.5 for employees under age 50 and $24.5 for employees 50 and older in calendar year 2018. Employee contributions are held in the employees’ name and invested by the plan’s trustee. The plan also permits the Company to make matching contributions, subject to established limits. The Company elected to match a portion of employee’s contributions to the plan in the amount of $185, $186 and $200 in 2018, 2017 and 2016, respectively.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies
Commitments and Contingencies	11. Commitments and Contingencies Operating Lease Commitments In 2015, the Company entered into a new office lease with respect to the Company’s current office space. The new office lease term commenced on May 1, 2015 with a three year term ending on April 30, 2018, with an option to extend the lease for an additional three years, and was accounted for as an operating lease. In March 2018, the Company amended the lease to extend the term of the lease for an additional 12-month term expiring on April 30, 2019. Total rent expense under the operating leases was approximately $509, $506 and $495 for the years ended December 31, 2018, 2017 and 2016, respectively. As of December 31, 2018, future annual minimum payments under operating lease arrangements were $162.

Quarterly Financial Data (Unaud

Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Data (Unaudited)
Quarterly Financial Data (Unaudited)	12. Quarterly Financial Data (Unaudited) (1) The following is a summary of the quarterly results of operations for the years ended December 31, 2018 and 2017: 2018 Quarters Ended March 31 June 30 September 30 December 31 Expenses: Research and development expenses $ 11,000 $ 7,962 $ 7,467 $ 3,240 General and administrative expenses 2,688 2,196 2,160 2,346 Total expenses 13,688 10,158 9,627 5,586 Loss from operations (13,688) (10,158) (9,627) (5,586) Other income, net 131 143 196 171 Net loss $ (13,557) $ (10,015) $ (9,431) $ (5,415) Net loss per share: Basic and Diluted $ (0.62) $ (0.43) $ (0.39) $ (0.23) Weighted average shares outstanding: Basic and Diluted 21,967,805 23,288,691 24,045,992 24,051,844 2017 Quarters Ended March 31 June 30 September 30 December 31 Expenses: Research and development expenses $ 4,193 $ 4,448 $ 5,914 $ 6,912 General and administrative expenses 2,087 1,997 2,617 2,487 Total expenses 6,280 6,445 8,531 9,399 Loss from operations (6,280) (6,445) (8,531) (9,399) Other income, net 27 40 27 122 Net loss $ (6,253) $ (6,405) $ (8,504) $ (9,277) Net loss per share: Basic and Diluted $ (0.39) $ (0.40) $ (0.53) $ (0.43) Weighted average shares outstanding: Basic and Diluted 16,018,342 16,041,923 16,115,835 21,541,909 (1) The sum of quarterly earnings per share amounts may not equal the annual amounts as the quarterly amounts are computed independently for each quarter while the full year is based on the annual weighted average shares outstanding.

Significant Accounting Polici_2

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Significant Accounting Policies
Basis of Presentation	Basis of Presentation The accompanying financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”). Additionally, GTx operates in one business segment.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual amounts and results could differ from those estimates.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers highly liquid investments with initial maturities of three months or less to be cash equivalents.
Short-term Investments	Short-term Investments At December 31, 2018 and 2017, short-term investments consisted of Federal Deposit Insurance Corporation (“FDIC”) insured certificates of deposit with original maturities of greater than three months and less than one year.
Property and Equipment	Property and Equipment Property and equipment is stated at cost. Amortization of leasehold improvements is recognized over the shorter of the estimated useful life of the leasehold improvement or the lease term. Depreciation is computed using the straight-line method over the estimated useful lives as follows: Office equipment 3 to 5 years Leasehold improvements 3 to 7 years Furniture and fixtures 5 years Computer equipment and software 3 years
Warrant Liability	Warrant Liability In November 2014, the Company issued warrants to purchase 6,430,948 shares of its common stock. The Company classified these warrants as a liability on its balance sheet since the warrants contained certain terms that could have required the Company (or its successor) to purchase the warrants for cash in an amount equal to the value (as calculated utilizing a contractually-agreed Black-Scholes-Merton option pricing valuation model ("Black-Scholes Model")) of the unexercised portion of the warrants in connection with certain change of control transactions occurring on or prior to December 31, 2016, with such cash payment capped at an amount equal to $1.25 per unexercised share underlying each warrant. As a result of the provision of the warrants requiring cash settlement upon certain change of control transactions, the Company was required to account for these warrants as a liability at fair value and the estimated warrant liability was required to be revalued at each balance sheet date until the earlier of the exercise of the warrants, the modification to remove the provision that could require cash settlement upon certain change of control transactions or the expiration of such provision on December 31, 2016. Effective March 25, 2016, each of the warrants was amended by agreement of the warrant holders to remove the provision that could require cash settlement upon certain change of control transactions. These warrants were no longer accounted for as a liability as of March 31, 2016. The Company recorded a non-cash reclassification of the warrant fair value to stockholders' equity based on the warrants' fair value as of the March 25, 2016 modification date, with no further adjustments to the fair value of these warrants being required.
Fair Value of Financial Instruments and Warrant Liability	Fair Value of Financial Instruments and Warrant Liability The carrying amounts of the Company’s financial instruments (which include cash, cash equivalents, short-term investments, and accounts payable) and its prior warrant liability approximate their fair values. The fair value of the warrant liability was estimated using the Black-Scholes-Merton Model. See Note 6, Stockholders' Equity, for additional disclosure on the valuation methodology and significant assumptions. The Company’s financial assets and liabilities are classified within a three-level fair value hierarchy that prioritizes the inputs used to measure fair value, which is defined as follows: Level 1 – Quoted prices in active markets for identical assets or liabilities that the Company has the ability to access at the measurement date Level 2 – Inputs other than quoted prices in active markets that are observable for the asset or liability, either directly or indirectly Level 3 – Inputs that are unobservable for the asset or liability As the Company has the positive intent and ability to hold its certificates of deposit classified as short-term investments until maturity, these investments have been classified as held to maturity investments and are stated at cost, which approximates fair value. The Company considers these to be Level 2 investments as the fair values of these investments are determined using third-party pricing sources, which generally utilize observable inputs, such as interest rates and maturities of similar assets.
Concentration of Risk	Concentration of Risk Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash and cash equivalents and short-term investments. The Company has established guidelines relating to diversification and maturities of its cash equivalents and short-term investments which are designed to manage risk. The Company’s cash and cash equivalents consist of bank deposits, certificates of deposit, and money market mutual funds. Bank deposits may at times be in excess of FDIC insurance limits. The Company’s short-term investments consist of FDIC insured certificates of deposit with original maturities of greater than three months and less than one year.
Research and Development Expenses	Research and Development Expenses Research and development expenses include, but are not limited to, the Company’s expenses for personnel, supplies, and facilities associated with research activities, screening and identification of product candidates, formulation and synthesis activities, manufacturing, preclinical studies, toxicology studies, clinical trials, regulatory and medical affairs activities, quality assurance activities and license fees. The Company expenses these costs in the period in which they are incurred. The Company estimates its liabilities for research and development expenses in order to match the recognition of expenses to the period in which the actual services are received. As such, accrued liabilities related to third party research and development activities are recognized based upon the Company’s estimate of services received and degree of completion of the services in accordance with the specific third party contract.
Patent Costs	Patent Costs The Company expenses patent costs, including legal expenses, in the period in which they are incurred. Patent expenses are included in general and administrative expenses in the Company’s statements of operations.
Income Taxes	Income Taxes The Company accounts for deferred taxes by recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements or tax returns. Under this method, deferred tax assets and liabilities are determined based on the difference between the financial statement and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. A valuation allowance is provided when it is more likely than not that some portion or all of the deferred tax assets will not be realized. Accordingly, at December 31, 2018 and December 31, 2017, net of the valuation allowance, the net deferred tax assets were reduced to zero. See Note 8, Income Taxes , for further discussion.
Share-Based Compensation	Share-Based Compensation The Company has stock option and equity incentive plans that provide for the purchase or acquisition of the Company’s common stock by certain of the Company’s employees and non-employees. The Company recognizes compensation expense for its share-based payments based on the fair value of the awards over the period during which an employee or non-employee is required to provide service in exchange for the award. See Note 3, Share-Based Compensation , for further discussion.
Other Income (Expense), net	Other Income (Expense), Net Other income (expense), net consists of interest earned on the Company’s cash, cash equivalents and short-term investments, foreign currency transaction gains and losses, and other non-operating income or expense.
Basic and Diluted Net Loss Per Share	Basic and Diluted Net Loss Per Share Basic and diluted net income (loss) per share attributable to common stockholders is calculated based on the weighted average number of common shares outstanding during the period. Diluted net income (loss) per share gives effect to the dilutive potential of common stock consisting of stock options, unvested RSUs and common stock warrants. Weighted average potential shares of common stock of 11,191,431, 9,438,236, and 8,162,347 were excluded from the calculation of diluted net loss per share for the years ended December 31, 2018, 2017 and 2016, respectively, as inclusion of the potential shares would have had an anti-dilutive effect on the net loss per share for the periods. At December 31, 2018, the Company had 24,051,844 shares of common stock outstanding.
Comprehensive Loss	Comprehensive Loss For all periods presented, there were no differences between net loss and comprehensive loss.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In February 2016, the Financial Accounting Standards Board issued Accounting Standard Update (“ASU”) 2016-02, Leases (Topic 842). This ASU requires that lessees recognize assets and liabilities on the balance sheet for the present value of the rights and obligations created by all leases with terms of more than 12 months. The ASU also will require disclosures designed to give financial statement users information on the amount, timing, and uncertainty of cash flows arising from leases. This new guidance will be effective for the Company as of January 1, 2019. The Company does not expect the adoption of the standard update to have a significant impact on its financial position or results of operations.
Subsequent Events	Subsequent Events The Company has evaluated all events or transactions that occurred after December 31, 2018 up through the date the financial statements were issued. Other than as set forth below, there were no material recognizable or nonrecognizable subsequent events during the period evaluated. Merger Agreement with Oncternal and Related Matters Merger Agreement On March 6, 2019, the Company entered into the Merger Agreement with Oncternal and Grizzly Merger Sub, Inc., a wholly-owned subsidiary of the Company ("Merger Sub"). Upon the terms and subject to the satisfaction of the conditions described in the Merger Agreement, including approval of the transaction by the Company's stockholders and Oncternal's stockholders, Merger Sub will be merged with and into Oncternal, with Oncternal surviving the Merger as a wholly-owned subsidiary of the Company. Subject to the terms and conditions of the Merger Agreement, at the effective time of the Merger (the "Effective Time"): (i) each share of Oncternal common stock outstanding immediately prior to the Effective Time (excluding shares held by the Company, Merger Sub or Oncternal and dissenting shares) will be converted solely into the right to receive a number of shares of the Company's common stock (the "Shares") equal to the exchange ratio described below, (ii) each outstanding Oncternal stock option will be assumed by the Company, and (iii) each outstanding Oncternal warrant will be assumed by the Company. Under the exchange ratio formula in the Merger Agreement, the former Oncternal stockholders immediately before the Merger are expected to own approximately 75% of the outstanding capital stock of the Company, and the stockholders of the Company immediately before the Merger are expected to own approximately 25% of the outstanding capital stock of the Company, subject to certain assumptions. The exchange ratio formula excludes Oncternal's outstanding stock options and warrants and the Company's outstanding stock options and warrants. Under certain circumstances further described in the Merger Agreement, the ownership percentages may be adjusted upward or downward based on cash levels of the respective companies at the closing of the Merger (the "Closing"). The Merger Agreement contains customary representations, warranties and covenants made by the Company and Oncternal, including covenants relating to obtaining the requisite approvals of the stockholders of the Company and Oncternal, indemnification of directors and officers, the Company’s and Oncternal’s conduct of their respective businesses between the date of signing of the Merger Agreement and the Closing. The Closing is subject to satisfaction or waiver of certain conditions included in the Merger Agreement. Following the Closing, Oncternal’s Chief Executive Officer, Chief Financial Officer, and Chief Operating Officer will serve in these positions for the Company. Additionally, following the Closing, the Company’s board of directors will consist of nine directors, including two current GTx board members. The Merger Agreement also includes termination provisions for both the Company and Oncternal. In connection with a termination of the Merger Agreement under specified circumstances, either party may be required to pay the other party a termination fee ranging between $500 to $2,000. Contingent Value Rights Agreement At the Effective Time, the Company will enter into a Contingent Value Rights Agreement (the "CVR Agreement"). Pursuant to the CVR Agreement, for each share of the Company's common stock held, the Company's stockholders of record as of immediately prior to the Effective Time will receive one contingent value right ("CVR") entitling such holders to receive in the aggregate 50% of any net proceeds received during the 15-year period after closing from the grant, sale or transfer of rights to the Company's SARD or SARM technology that occurs during the 10-year period after the Closing (or in the 11th year if based on a term sheet approved during the initial 10-year period) and, if applicable, to receive royalties on the sale of any SARD products by the combined company during the 15-year period after Closing. The CVR Agreement will be effective prior to the Closing and will continue in effect until the payment of all amounts payable thereunder, unless terminated upon termination of the Merger Agreement. Workforce Reduction In the first quarter of 2019, due to the entry into the Merger Agreement with Oncternal, the Company's board of directors committed to reducing its workforce by seven employees. All employees affected by the workforce reduction will be eligible to receive, among other things, specified severance payments based on the applicable employee's level and years of service with the Company and the continuation of group health insurance coverage. In addition, the affected employees will also be eligible for full vesting acceleration of their outstanding stock options as well as an extension of the post-termination exercise period for their outstanding stock options. As a result of the workforce reduction and prior termination of three employees earlier in the first quarter of 2019, the Company estimates that it will incur total severance-related charges for these employees of approximately $1,000 in the first quarter of 2019 and up to an additional $500 contingent upon the closing of the Merger. The Company does not expect to record a non-cash charge related to the modification of outstanding stock options in connection with the workforce reduction. Termination of Directors' Deferred Compensation Plan Prior to the Effective Time (but in no event more than 30 days prior to the Effective Time), the Company’s board of directors will take all actions necessary to terminate and liquidate the Company’s 2018 Amended and Restated Directors’ Deferred Compensation Plan (the “Directors’ Deferred Compensation Plan”) and all rights or other deferrals thereunder effective immediately prior to the Effective Time, subject to the consummation of the Merger. Any future board compensation under the Directors’ Deferred Compensation Plan on or after January 3, 2019 shall be settled only in cash.

Significant Accounting Polici_3

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2018
Significant Accounting Policies
Schedule of estimated useful lives of property and equipment	Office equipment 3 to 5 years Leasehold improvements 3 to 7 years Furniture and fixtures 5 years Computer equipment and software 3 years

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2018
Share-Based Compensation
Summary of share-based compensation expense	Years Ended December 31, 2018 2017 2016 Research and development expenses $ 807 $ 1,171 $ 1,260 General and administrative expenses 1,556 2,146 1,829 Total share-based compensation $ 2,363 $ 3,317 $ 3,089
Schedule of assumptions used to estimate fair value of options granted	Years Ended December 31, 2018 2017 2016 Expected price volatility 93.1 % 88.6 % 91.3 % Risk-free interest rate 2.4 % 2.2 % 2.0 % Weighted average expected life in years years 6.9 years 6.9 years Dividend yield 0 % 0 % 0 %
Summary of stock option transactions	Weighted Average Number of Exercise Price Shares Per Share Options outstanding at January 1, 2016 798,309 $ 38.80 Options granted 363,500 6.94 Options forfeited or expired (71,829) 54.65 Options exercised — — Options outstanding at December 31, 2016 1,089,980 27.13 Options granted 977,350 4.97 Options forfeited or expired (166,834) 48.71 Options exercised — — Options outstanding at December 31, 2017 1,900,496 13.84 Options granted 472,000 13.32 Options forfeited or expired (31,049) 168.76 Options exercised (6,000) 17.23 Options outstanding and vested or expected to vest at December 31, 2018 2,335,447 $ 11.67
Summary of information about stock options	Options Outstanding Options Exercisable Weighted Average Weighted Weighted Remaining Average Average Number Contractual Exercise Number Exercise Exercise Price Outstanding Life (years) Price Exercisable Price $4.29 - $4.29 56,250 $ 4.29 18,750 $ 4.29 $4.71 - $4.71 825,000 4.71 22,500 4.71 $4.77 - $12.71 826,800 9.97 134,404 8.25 $12.95 - $108.90 627,397 23.71 508,691 25.59 2,335,447 11.67 684,345 20.91
Summary of RSU transactions	Number of Shares Nonvested RSUs outstanding at January 1, 2016 820,000 RSUs granted 11,000 RSUs vested (184,001) RSUs forfeited (62,000) Nonvested RSUs outstanding at December 31, 2016 584,999 RSUs granted — RSUs vested (168,499) RSUs forfeited (36,000) Nonvested RSUs outstanding at December 31, 2017 380,500 RSUs granted — RSUs vested (380,500) RSUs forfeited — Nonvested RSUs outstanding at December 31, 2018 —

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2018
Property and Equipment, Net
Schedule of property and equipment, net	December 31, 2018 2017 Computer equipment and software $ 1,225 $ 1,299 Furniture and fixtures 853 853 Leasehold improvements 355 355 Office equipment 211 211 2,644 2,718 Less: accumulated depreciation (2,625) (2,667) $ 19 $ 51

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2018
Accrued Expenses and Other Current Liabilities
Schedule of accrued expenses and other current liabilities	December 31, 2018 2017 Clinical trials $ 1,492 $ 4,742 General and administrative 101 314 Research and development 272 312 Employee compensation 66 3 $ 1,931 $ 5,371

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Taxes
Schedule of principal components of the Company's net deferred income tax assets and liabilities	December 31, 2018 2017 Deferred income tax assets: Net federal and state operating loss carryforwards $ 120,555 $ 110,145 Research and development credits 16,383 14,757 Share-based compensation 3,130 3,994 Depreciation and amortization 17 21 Total deferred tax assets 140,085 128,917 Deferred income tax liabilities: Other 461 92 Total deferred tax liabilities 461 92 Net deferred tax assets 139,624 128,825 Valuation allowance (139,624) (128,825) $ — $ —

Quarterly Financial Data (Una_2

Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Data (Unaudited)
Summary of the quarterly results of operations	2018 Quarters Ended March 31 June 30 September 30 December 31 Expenses: Research and development expenses $ 11,000 $ 7,962 $ 7,467 $ 3,240 General and administrative expenses 2,688 2,196 2,160 2,346 Total expenses 13,688 10,158 9,627 5,586 Loss from operations (13,688) (10,158) (9,627) (5,586) Other income, net 131 143 196 171 Net loss $ (13,557) $ (10,015) $ (9,431) $ (5,415) Net loss per share: Basic and Diluted $ (0.62) $ (0.43) $ (0.39) $ (0.23) Weighted average shares outstanding: Basic and Diluted 21,967,805 23,288,691 24,045,992 24,051,844 2017 Quarters Ended March 31 June 30 September 30 December 31 Expenses: Research and development expenses $ 4,193 $ 4,448 $ 5,914 $ 6,912 General and administrative expenses 2,087 1,997 2,617 2,487 Total expenses 6,280 6,445 8,531 9,399 Loss from operations (6,280) (6,445) (8,531) (9,399) Other income, net 27 40 27 122 Net loss $ (6,253) $ (6,405) $ (8,504) $ (9,277) Net loss per share: Basic and Diluted $ (0.39) $ (0.40) $ (0.53) $ (0.43) Weighted average shares outstanding: Basic and Diluted 16,018,342 16,041,923 16,115,835 21,541,909 (1) The sum of quarterly earnings per share amounts may not equal the annual amounts as the quarterly amounts are computed independently for each quarter while the full year is based on the annual weighted average shares outstanding.

Business (Details)

Business (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Business
Cash, cash equivalents and short-term investments	$ 28,458	$ 43,899

Significant Accounting Polici_4

Significant Accounting Policies - Basis of Presentation (Details)	12 Months Ended
	Dec. 31, 2018item
Basis of presentation
Number of Operating Segments	1

Significant Accounting Polici_5

Significant Accounting Policies - Property and Equipment (Details)	12 Months Ended
	Dec. 31, 2018
Office equipment | Minimum
Property and Equipment
Estimated useful lives	3 years
Office equipment | Maximum
Property and Equipment
Estimated useful lives	5 years
Leasehold improvements | Minimum
Property and Equipment
Estimated useful lives	3 years
Leasehold improvements | Maximum
Property and Equipment
Estimated useful lives	7 years
Furniture and fixtures
Property and Equipment
Estimated useful lives	5 years
Computer equipment and software
Property and Equipment
Estimated useful lives	3 years

Significant Accounting Polici_6

Significant Accounting Policies - Warrant Liability (Details) - Private Placement, November 2014	Nov. 14, 2014$ / sharesshares
Warrant Liability
Warrants issued to purchase shares under private placement | shares	6,430,948
Maximum contingent per share cash settlement price (in dollars per share) | $ / shares	$ 1.25

Significant Accounting Polici_7

Significant Accounting Policies - Income Taxes (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Income Taxes
Net deferred tax assets	$ 0	$ 0

Significant Accounting Polici_8

Significant Accounting Policies - Basic and Diluted Net Loss Per Share (Details) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Basic and Diluted Net Loss Per Share
Weighted average potential shares of common stock excluded from calculation of diluted net loss per share	11,191,431	9,438,236	8,162,347
Common stock, shares outstanding	24,051,844	21,541,909

Significant Accounting Polici_9

Significant Accounting Policies - Subsequent Events - Merger Agreement with Oncternal and Related Matters (Details) $ in Thousands	Mar. 06, 2019USD ($)directoritem	Mar. 31, 2019USD ($)employee	Jun. 30, 2019USD ($)
Subsequent Events
Ownership percentage of stockholders upon closing of the merger	25.00%
Number of directors on the Board of Directors upon closing of the merger | director	9
Number of GTx designees on the Board of Directors upon closing of the merger | director	2
Forecast
Subsequent Events
Severance-related charges		$ 1,000	$ 500
Minimum
Subsequent Events
Potential termination fee payable upon termination of the merger agreement	$ 500
Maximum
Subsequent Events
Potential termination fee payable upon termination of the merger agreement	$ 2,000
CVR Agreement
Subsequent Events
Contingent value right per common stock | item	1
Percentage of net proceeds entitled to be received per CVR	50.00%
Period from closing during which payment of percentage of net proceeds would be payable under the CVR	15 years
Period from closing during which the grant, sale or transfer of rights to the Company's SARD or SARM technology could trigger a payment under the CRV Agreement	10 years
Merger Agreement / Oncternal Therapeutics Inc. stockholders
Subsequent Events
Ownership percentage of stockholders upon closing of the merger	75.00%
Subsequent Event
Subsequent Events
Number of employees terminated upon entry into the merger agreement | employee		7
Number of employees terminated prior to the merger agreement | employee		3

Share-Based Compensation - Shar

Share-Based Compensation - Share-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based compensation expense
Total share-based compensation	$ 2,363	$ 3,317	$ 3,089
Share-based compensation expense related to deferred compensation arrangements for non-employee directors	166	166	132
Research and development expenses
Share-based compensation expense
Total share-based compensation	807	1,171	1,260
General and administrative expenses
Share-based compensation expense
Total share-based compensation	1,556	2,146	1,829
Director
Share-based compensation expense
Share-based compensation expense related to deferred compensation arrangements for non-employee directors	166	166	132
Director | General and administrative expenses
Share-based compensation expense
Share-based compensation expense related to deferred compensation arrangements for non-employee directors	$ 166	$ 166	$ 132
Stock Options | Maximum
Share-based compensation expense
Term of options from the grant date	10 years
Stock Options | Director
Share-based compensation expense
Vesting period	3 years
Stock Options | Employees
Share-based compensation expense
Period available to exercise all vested options after end of employment relationship	3 months
Stock Options | Employees | Maximum
Share-based compensation expense
Vesting period	5 years

Share-Based Compensation - Stoc

Share-Based Compensation - Stock Option Activity (Details) - Stock Options - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based compensation
Weighted average grant date fair value (in dollars per share)	$ 10.36	$ 3.80	$ 5.45
Stock-based compensation options granted
Expected price volatility (as a percent)	93.10%	88.60%	91.30%
Risk-free interest rate (as a percent)	2.40%	2.20%	2.00%
Weighted average expected life in years	6 years 10 months 24 days	6 years 10 months 24 days	6 years 10 months 24 days
Dividend yield (as a percent)	0.00%	0.00%	0.00%
Number of Shares
Options outstanding at the beginning of the period (in shares)	1,900,496	1,089,980	798,309
Options granted (in shares)	472,000	977,350	363,500
Options forfeited or expired (in shares)	(31,049)	(166,834)	(71,829)
Options exercised (in shares)	(6,000)
Options outstanding at the end of the period (in shares)	2,335,447	1,900,496	1,089,980
Options vested or expected to vest at the end of the period (in shares)	2,335,447
Weighted Average Exercise Price Per Share
Options outstanding at the beginning of the period (in dollars per share)	$ 13.84	$ 27.13	$ 38.80
Options granted (in dollars per share)	13.32	4.97	6.94
Options forfeited or expired (in dollars per share)	168.76	48.71	54.65
Options exercised (in dollars per share)	17.23
Options outstanding at the end of the period (in dollars per share)	11.67	$ 13.84	$ 27.13
Options vested or expected to vest at the end of the period (in dollars per share)	$ 11.67
Maximum
Stock-based compensation options granted
Option term	10 years

Share-Based Compensation - St_2

Share-Based Compensation - Stock Options Outstanding (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Jan. 01, 2018
Additional information
Shares available for future issuance under the Company's stock option and equity incentive plans	1,167,162
Increase to shares available for future issuance in accordance with annual automatic increase provisions		1,012,074
Stock Options
Information about stock options outstanding
Options Outstanding, Number Outstanding (in shares)	2,335,447
Options Outstanding, Weighted Average Remaining Contractual Life	6 years 10 months 17 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 11.67
Options Exercisable, Number Exercisable (in shares)	684,345
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 20.91
Additional information
Aggregate intrinsic value of all outstanding options (in dollars)	$ 0
Outstanding options, weighted average remaining contractual term	6 years 10 months 17 days
Options exercisable, weighted average remaining contractual term	4 years 18 days
Options exercisable, aggregate intrinsic value (in dollars)	$ 0
Vested and expected to vest options, weighted average remaining contractual term	6 years 10 months 17 days
Vested and expected to vest options, aggregate intrinsic value (in dollars)	$ 0
Options exercised (in shares)	6,000
Intrinsic value of options exercised (in dollars)	$ 39
Compensation cost related to non-vested options not yet recognized	$ 7,697
Weighted average expense recognition period related to non-vested options not yet recognized	2 years 11 months 12 days
Stock Options | $4.29 - $4.29
Information about stock options outstanding
Low end of range of exercise prices (in dollars per share)	$ 4.29
High end of range of exercise prices (in dollars per share)	$ 4.29
Options Outstanding, Number Outstanding (in shares)	56,250
Options Outstanding, Weighted Average Remaining Contractual Life	8 years 4 months 10 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 4.29
Options Exercisable, Number Exercisable (in shares)	18,750
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 4.29
Stock Options | $4.71 - $4.71
Information about stock options outstanding
Low end of range of exercise prices (in dollars per share)	4.71
High end of range of exercise prices (in dollars per share)	$ 4.71
Options Outstanding, Number Outstanding (in shares)	825,000
Options Outstanding, Weighted Average Remaining Contractual Life	8 years 7 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 4.71
Options Exercisable, Number Exercisable (in shares)	22,500
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 4.71
Stock Options | $4.77 - $12.71
Information about stock options outstanding
Low end of range of exercise prices (in dollars per share)	4.77
High end of range of exercise prices (in dollars per share)	$ 12.71
Options Outstanding, Number Outstanding (in shares)	826,800
Options Outstanding, Weighted Average Remaining Contractual Life	7 years 8 months 1 day
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 9.97
Options Exercisable, Number Exercisable (in shares)	134,404
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 8.25
Stock Options | $12.95 - $108.90
Information about stock options outstanding
Low end of range of exercise prices (in dollars per share)	12.95
High end of range of exercise prices (in dollars per share)	$ 108.90
Options Outstanding, Number Outstanding (in shares)	627,397
Options Outstanding, Weighted Average Remaining Contractual Life	4 years 2 months 12 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 23.71
Options Exercisable, Number Exercisable (in shares)	508,691
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 25.59

Share-Based Compensation - RSU

Share-Based Compensation - RSU Activity (Details) - Restricted Stock Units (RSUs) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Number of Shares
Nonvested RSUs at the beginning of the period (in shares)	380,500	584,999	820,000
RSUs granted (in shares)			11,000
RSUs vested (in shares)	(380,500)	(168,499)	(184,001)
RSUs forfeited (in shares)		(36,000)	(62,000)
Nonvested RSUs at the end of the period (in shares)		380,500	584,999
Vested shares withheld to satisfy statutory tax withholding requirements	52,645	29,482	29,829

Property and Equipment, Net (De

Property and Equipment, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property and equipment
Property and Equipment, gross	$ 2,644	$ 2,718
Less: accumulated depreciation	(2,625)	(2,667)
Property and Equipment, Net	19	51
Depreciation and amortization expense	32	32	$ 14
Research and development expenses
Property and equipment
Depreciation and amortization expense	1	2	$ 2
Computer equipment and software
Property and equipment
Property and Equipment, gross	1,225	1,299
Furniture and fixtures
Property and equipment
Property and Equipment, gross	853	853
Leasehold improvements
Property and equipment
Property and Equipment, gross	355	355
Office equipment
Property and equipment
Property and Equipment, gross	$ 211	$ 211

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accrued Expenses and Other Current Liabilities
Clinical trials	$ 1,492	$ 4,742
General and administrative	101	314
Research and development	272	312
Employee compensation	66	3
Accrued expenses and other current liabilities	$ 1,931	$ 5,371

Stockholders' Equity (Details)

Stockholders' Equity (Details) $ / shares in Units, $ in Thousands

May 16, 2018USD ($)shares

Sep. 29, 2017USD ($)$ / sharesshares

Dec. 05, 2016shares

Oct. 14, 2016USD ($)shares

May 06, 2015$ / shares

Nov. 14, 2014USD ($)$ / sharesshares

Mar. 31, 2018shares

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

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

Dec. 31, 2016USD ($)

Feb. 09, 2018USD ($)

Dec. 04, 2016shares

Authorized Capital

Reverse stock split of outstanding common stock

10

Common Stock, Shares authorized

60,000,000

60,000,000

60,000,000

400,000,000

Common Stock, Par value (in dollars per share) | $ / shares

$ 0.001

$ 0.001

Preferred stock shares authorized

5,000,000

Par value per share (in dollars per share) | $ / shares

$ 0.001

Common stock

Net proceeds from the issuance of common stock and warrants | $

$ 24,474

$ 45,648

$ 13,692

At-The-Market Equity Offering

Common stock

Common stock value that may be sold under the At-the-Market Equity Offering Sales Agreement | $

$ 50,000

Common stock sold under the ATM Sales Agreement

1,501,501

Net proceeds from the issuance of common stock and warrants | $

$ 24,474

Remaining common stock value that is available and may be sold under the At-the-Market Equity Offering Sales Agreement | $

$ 25,000

Private Placement, September 2017

Common stock

Proceeds from issue of new stock or shares (in shares)

5,483,320

Warrants issued to purchase shares under private placement

3,289,988

Net proceeds from private placement after deducting offering expenses | $

$ 45,648

Warrant term

5 years

Exercise price (in dollars per share) | $ / shares

$ 9.02

Estimated fair value of warrants | $

$ 21,069

Expected volatility of warrants (as a percent)

97.00%

Risk-free interest rate of warrants (as a percent)

1.92%

Expected life of warrants

5 years

Expected dividends on warrants (in dollars per share) | $ / shares

$ 0

Shares issued under direct offering

5,483,320

Direct Offering, October 2016

Common stock

Proceeds from issue of new stock or shares (in shares)

1,728,395

Shares issued under direct offering

1,728,395

Net cash proceeds from public offering after deducting offering expenses | $

$ 13,692

Private Placement, November 2014

Common stock

Proceeds from issue of new stock or shares (in shares)

6,431,111

Warrants issued to purchase shares under private placement

6,430,948

Net proceeds from private placement after deducting offering expenses | $

$ 42,814

Warrant term

4 years

Exercise price (in dollars per share) | $ / shares

$ 8.50

Shares issued under direct offering

6,431,111

Maximum contingent per share cash settlement price (in dollars per share) | $ / shares

$ 1.25

Warrants exercised

1,111,082

Common stock issued upon exercise of warrants

674,579

License Agreements (Details)

License Agreements (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Jul. 31, 2007
Intangible assets, net
Intangible assets, net	$ 94	$ 108
SARM License Agreement
Intangible assets, net
One-time up-front fee			$ 290
Intangible assets, net	$ 94	$ 108

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
U.S. corporate tax rate (as a percent)	21.00%	35.00%
Deferred income tax assets:
Net federal and state operating loss carryforwards	$ 120,555	$ 110,145
Research and development credits	16,383	14,757
Share-based compensation	3,130	3,994
Depreciation and amortization	17	21
Total deferred tax assets	140,085	128,917
Deferred income tax liabilities:
Other	461	92
Total deferred tax liabilities	461	92
Net deferred tax assets	139,624	128,825
Valuation allowance	(139,624)	(128,825)
Net deferred tax assets and liabilities	0	0
Valuation allowance disclosure
Increase (Decrease) in valuation allowance	10,799	$ (47,132)	$ 9,347
Tax credits
Unrecognized Tax Benefits	0
Federal
Valuation allowance disclosure
Net operating loss carryforwards	472,054
State
Valuation allowance disclosure
Net operating loss carryforwards	$ 411,396

Directors' Deferred Compensat_2

Directors' Deferred Compensation Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Directors' deferred compensation plan
Non-employee director fee expense which was deferred into stock accounts	$ 166	$ 166	$ 132
Director
Directors' deferred compensation plan
Non-employee director fee expense	291	291	257
Non-employee director fee expense which was deferred into stock accounts	$ 166	$ 166	$ 132
Shares of common stock credited to individual director stock accounts under the Directors' Deferred Compensation Plan	122,725
Amount credited to individual director cash accounts under the Directors' Deferred Compensation Plan	$ 0

401(k) Plan (Details)

401(k) Plan (Details)	12 Months Ended
	Dec. 31, 2018USD ($)item	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
401(k) Plan
Maximum annual contribution per employee who is under the specified age in the current calendar year	$ 18,500
Age specified for current calendar year to determine employee's contribution | item	50
Maximum annual contribution per employee who is equal to specified age and older in the current calendar year	$ 24,500
Company's matching contribution to the plan	$ 185,000	$ 186,000	$ 200,000

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($) $ in Thousands	May 01, 2015	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Commitments and Contingencies
Initial term of lease arrangement	3 years
Option to extend lease	3 years
Amended lease extend term		12 months
Rent expense under operating leases			$ 509	$ 506	$ 495
Operating Lease Commitments
Future annual minimum payments under operating lease arrangements			$ 162

Quarterly Financial Data (Una_3

Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Expenses:
Research and development expenses	$ 3,240	$ 7,467	$ 7,962	$ 11,000	$ 6,912	$ 5,914	$ 4,448	$ 4,193	$ 29,669	$ 21,467	$ 17,228
General and administrative expenses	2,346	2,160	2,196	2,688	2,487	2,617	1,997	2,087	9,390	9,188	8,705
Total expenses	5,586	9,627	10,158	13,688	9,399	8,531	6,445	6,280	39,059	30,655	25,933
Loss from operations	(5,586)	(9,627)	(10,158)	(13,688)	(9,399)	(8,531)	(6,445)	(6,280)	(39,059)	(30,655)	(25,933)
Other income, net	171	196	143	131	122	27	40	27	641	216	46
Net loss	$ (5,415)	$ (9,431)	$ (10,015)	$ (13,557)	$ (9,277)	$ (8,504)	$ (6,405)	$ (6,253)	$ (38,418)	$ (30,439)	$ (17,724)
Net loss per share:
Basic and Diluted (in dollars per share)	$ (0.23)	$ (0.39)	$ (0.43)	$ (0.62)	$ (0.43)	$ (0.53)	$ (0.40)	$ (0.39)	$ (1.65)	$ (1.75)	$ (1.22)
Weighted average shares outstanding:
Basic and Diluted (in shares)	24,051,844	24,045,992	23,288,691	21,967,805	21,541,909	16,115,835	16,041,923	16,018,342	23,346,231	17,441,280	14,559,541