Oncternal Therapeutics (ONCT) 10-K16 Mar 152014 FY Annual reportFinancial data

Company Profile

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
Document and Entity Information (USD $)	Dec. 31, 2014	Mar. 09, 2015	Jun. 30, 2014
Document and Entity Information
Entity Registrant Name	GTX INC /DE/
Entity Central Index Key	1260990
Document Type	10-K
Document Period End Date	31-Dec-14
Amendment Flag	FALSE
Current Fiscal Year End Date	-19
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Public Float			$50,111,518
Entity Common Stock, Shares Outstanding		140,325,643
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY

BALANCE_SHEETS

BALANCE SHEETS (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$17,880	$14,529
Short-term investments	31,415	200
Prepaid expenses and other current assets	856	442
Total current assets	50,151	15,171
Property and equipment, net	29	112
Intangible and other assets, net	471	322
Total assets	50,651	15,605
Current liabilities:
Accounts payable	512	808
Warrant liability	30,430
Accrued expenses and other current liabilities	1,850	3,759
Total current liabilities	32,792	4,567
Other long-term liabilities	30	354
Commitments and contingencies
Stockholders' equity:
Common stock, $0.001 par value: 200,000,000 and 120,000,000 shares authorized at December 31, 2014 and December 31, 2013, respectively; 140,325,643 and 63,185,389 shares issued and outstanding at December 31, 2014 and December 31, 2013, respectively	140	63
Additional paid-in capital	512,460	465,981
Accumulated deficit	-494,771	-455,360
Total stockholders' equity	17,829	10,684
Total liabilities and stockholders' equity	$50,651	$15,605

BALANCE_SHEETS_Parenthetical

BALANCE SHEETS (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
BALANCE SHEETS
Common stock, par value (in dollars per share)	$0.00	$0.00
Common stock, shares authorized	200,000,000	120,000,000
Common stock, shares issued	140,325,643	63,185,389
Common stock, shares outstanding	140,325,643	63,185,389

STATEMENTS_OF_OPERATIONS

STATEMENTS OF OPERATIONS (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Expenses:
Research and development expenses	$20,870	$32,318	$38,887
General and administrative expenses	9,478	11,281	10,845
Total expenses	30,348	43,599	49,732
Loss from operations	-30,348	-43,599	-49,732
Other income (expense), net	-259	1,488	-19
Loss on change in fair value of warrant liability	-8,804
Loss from operations before income taxes	-39,411	-42,111	-49,751
Income tax benefit			8,821
Net loss from continuing operations	-39,411	-42,111	-40,930
Income from discontinued operations before income taxes			22,676
Income tax expense			-8,821
Net income from discontinued operations			13,855
Net loss	($39,411)	($42,111)	($27,075)
Net (loss) income per share - basic and diluted:
Net loss from continuing operations (in dollars per share)	($0.48)	($0.67)	($0.65)
Net income from discontinued operations (in dollars per share)			$0.22
Net loss per share (in dollars per share)	($0.48)	($0.67)	($0.43)
Weighted average shares outstanding:
Basic and diluted (in shares)	81,807,706	63,057,142	62,809,219

STATEMENTS_OF_STOCKHOLDERS_EQU

STATEMENTS OF STOCKHOLDERS' EQUITY (USD $)	Common Stock	Common Stock	Common Stock	Additional Paid-in Capital	Additional Paid-in Capital	Additional Paid-in Capital	Retained Earnings	Private Placement, March 2014	Private Placement, November 2014	Total
In Thousands, except Share data, unless otherwise specified	Private Placement, March 2014	Private Placement, November 2014	Common Stock	Private Placement, March 2014	Private Placement, November 2014	Additional Paid-in Capital	Retained Earnings	Private Placement, March 2014	Private Placement, November 2014	Total
Balance at Dec. 31, 2011			$63			$457,985	($386,174)			$71,874
Balance (in shares) at Dec. 31, 2011			62,790,223
Increase (Decrease) in Stockholders' Equity
Exercise of employee stock options						85				85
Exercise of employee stock options (in shares)			28,201							28,201
Directors' deferred compensation						169				169
Share-based compensation						2,648				2,648
Net loss							-27,075			-27,075
Balance at Dec. 31, 2012			63			460,887	-413,249			47,701
Balance (in shares) at Dec. 31, 2012			62,818,424
Increase (Decrease) in Stockholders' Equity
Issuance of common stock under deferred compensation arrangements (in shares)			45,667
Exercise of employee stock options						1,226				1,226
Exercise of employee stock options (in shares)			321,298							321,298
Directors' deferred compensation						135				135
Share-based compensation						3,733				3,733
Net loss							-42,111			-42,111
Balance at Dec. 31, 2013			63			465,981	-455,360			10,684
Balance (in shares) at Dec. 31, 2013			63,185,389							63,185,389
Increase (Decrease) in Stockholders' Equity
Issuance of common stock and warrants in private placement, net of offering costs	12	64		21,123	21,420			21,135	21,484
Issuance of common stock in private placement (in shares)	11,976,048	64,311,112
Exercise of employee stock options (in shares)										0
Vesting of restricted stock units, net of shares withheld for tax payments			1			-617				-616
Vesting of restricted stock units, net of shares withheld for tax payments (in shares)			853,094
Directors' deferred compensation						125				125
Share-based compensation						4,428				4,428
Net loss							-39,411			-39,411
Balance at Dec. 31, 2014			$140			$512,460	($494,771)			$17,829
Balance (in shares) at Dec. 31, 2014			140,325,643							140,325,643

STATEMENTS_OF_CASH_FLOWS

STATEMENTS OF CASH FLOWS (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities:
Net loss	($39,411)	($42,111)	($27,075)
Adjustments to reconcile net loss to net cash used in operating activities:
Loss on change in fair value of warrant liability	8,804
Private placement expenses recorded as other income (expense), net	297
Gain on sale of FARESTON			-18,831
Share-based compensation	4,428	3,733	2,648
Directors' deferred compensation	125	135	169
Depreciation and amortization	102	384	750
Gain on sale of property and equipment		-1,366
Changes in assets and liabilities:
Prepaid expenses and other assets	-577	399	1,857
Accounts payable	-296	-899	488
Accrued expenses and other liabilities	-2,231	-4,246	2,885
Net cash used in operating activities	-28,759	-43,971	-37,109
Cash flows from investing activities:
Purchase of property and equipment	-5	-32	-142
Proceeds from the sale of property and equipment		1,424
Purchase of short-term investments, held to maturity	-41,905	-1,425	-11,980
Proceeds from maturities of short-term investments, held to maturity	10,690	9,270	14,630
Proceeds from the sale of FARESTON, net of cash expenses			18,897
Net cash (used in) provided by investing activities	-31,220	9,237	21,405
Cash flows from financing activities:
Net proceeds from the issuance of common stock and warrants	63,949
Tax payments related to shares withheld for vested restricted stock units	-617
Proceeds from exercise of employee stock options		1,226	85
Payments on capital lease and financed equipment obligations	-2	-7	-82
Net cash provided by financing activities	63,330	1,219	3
Net (decrease) increase in cash and cash equivalents	3,351	-33,515	-15,701
Cash and cash equivalents, beginning of period	14,529	48,044	63,745
Cash and cash equivalents, end of period	$17,880	$14,529	$48,044

Business

Business	12 Months Ended
Business	Dec. 31, 2014
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 small molecules for the treatment of cancer, including treatments for breast and prostate cancer, and other serious medical conditions.
	The Company is developing selective androgen receptor modulators ("SARMs"), including its lead product candidate, enobosarm (GTx-024). SARMs are a new class of drugs that the Company believes have the potential to be used as a novel hormonal therapy for the treatment of advanced breast cancer, as well as the potential to prevent and treat muscle wasting in patients with cancer and other musculoskeletal wasting or muscle loss conditions. The Company announced during the second quarter of 2014 positive results from an ongoing Phase 2 proof-of-concept, open-label clinical trial evaluating a 9 mg oral daily dose of enobosarm for the treatment of patients with estrogen receptor ("ER") positive and androgen receptor ("AR") positive metastatic breast cancer who have previously responded to hormonal therapy. The Company's current strategy is focused on further development of enobosarm in two breast cancer indications targeting the androgen receptor. Subject to the receipt of necessary regulatory approvals, the Company plans to initiate a Phase 2 proof-of-concept clinical trial of enobosarm in the second quarter of 2015 that is designed to evaluate the efficacy and safety of enobosarm in patients with advanced AR positive triple-negative breast cancer. Subject to the receipt of necessary regulatory approvals, the Company also plans to initiate a second Phase 2 clinical trial in the third quarter of 2015 evaluating enobosarm in patients with ER positive and AR positive advanced breast cancer.
	The Company announced in August 2013 that its POWER 1 (platinum plus taxane chemotherapy) and POWER 2 (platinum plus non-taxane chemotherapy) Phase 3 clinical trials evaluating enobosarm 3 mg daily for the prevention and treatment of muscle wasting in patients with advanced non-small cell lung cancer ("NSCLC") failed to meet the statistical criterion for the co-primary endpoints of lean body mass and physical function that were assessed using responder analyses as pre-specified for the United States Food and Drug Administration ("FDA"). Based upon input from representatives from the FDA and from member countries to the European Medicines Agency ("EMA"), the Company believes that the data from the POWER trials is not sufficient to support the filing and approval of a new drug application in the United States or a marketing authorization application in the European Union for enobosarm 3 mg for the prevention and treatment of muscle wasting in patients with advanced NSCLC. The Company's strategy does not currently include further development of enobosarm for this indication in the United States or in the European Union unless such development is part of a third-party collaborative arrangement or strategic partnership.
	Additionally, the Company is developing GTx-758 (Capesaris®), an oral nonsteroidal selective estrogen receptor alpha agonist, for secondary hormonal therapy in men with castration resistant prostate cancer, and, potentially, as a secondary hormonal treatment for advanced prostate cancer used in combination with androgen deprivation therapy. The Company is presently conducting a Phase 2 clinical trial evaluating GTx-758 as a secondary hormonal therapy in men with metastatic and high risk non-metastatic castration resistant prostate cancer.

Significant_Accounting_Policie

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
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, 2014 and 2013, 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:

		Laboratory and 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
	On November 14, 2014, the Company issued warrants to purchase 64,311,112 shares of its common stock. The Company classifies the warrants as a liability on its balance sheet since the warrants contain certain terms that could require 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 option pricing formula) 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 $0.125 per unexercised share underlying each warrant. In addition, each warrant is subject to net cash settlement if, at the time of any exercise, there are then an insufficient number of authorized and reserved shares of common stock to effect a share settlement of the warrant. As of December 31, 2014, the Company did not have a sufficient number of authorized and reserved shares of common stock to effect the share settlement of all of these warrants; however, these warrants were not exercisable at December 31, 2014.
	As a result of the foregoing provisions, the Company is required to account for these warrants as a liability at fair value and the estimated warrant liability is required to be revalued at each balance sheet date until the earlier of the exercise of the warrants or, assuming stockholder approval is obtained for the authorization of additional common stock, the expiration of the provision on December 31, 2016 that could require cash settlement upon certain change of control transactions. Upon the exercise of the warrants or, assuming stockholder approval is obtained for the authorization of additional common stock, the expiration of the provision on December 31, 2016 that could require cash settlement upon certain change of control transactions, the fair value of the warrants will be reclassified from a liability to stockholders' equity on the Company's balance sheets and no further adjustment to the fair value would be made in subsequent periods. See Note 6, Stockholders' Equity, for further information regarding these warrants and the Company's valuation of the 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 warrant liability approximate their fair values. The fair value of the warrant liability is estimated using the Black-Scholes-Merton pricing valuation 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
	Asset and liabilities measured at fair value on a recurring basis as of December 31, 2014 included only the Company's warrant liability of $30,430, which was classified within Level 3 of the hierarchy. As of December 31, 2013, the Company had no assets or liabilities measured at fair value on a recurring basis within Level 3 of the hierarchy. A loss of $8,804 related to the change in the fair value of the warrant liability was recognized during the year ended December 31, 2014 as a non-cash loss in the Company's statement of operations.
	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, 2014 and December 31, 2013, net of the valuation allowance, the net deferred tax assets were reduced to zero. See Note 9, Income Taxes, for further discussion.
	The Company has recognized the tax effect of discontinued operations in the statement of operations for the year ended December 31, 2012 in accordance with the intra-period accounting rules. An offsetting tax benefit was recorded in continuing operations for the year ended December 31, 2012 in relation to the tax expense that was recognized for discontinued operations.
	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 foreign currency transaction gains and losses, interest earned on the Company's cash, cash equivalents and short-term investments, interest expense, and other non-operating income or expense. Other income (expense), net for the year ended December 31, 2014 also included expenses related to the private placement of common stock and warrants completed in November 2014 as the warrants issued were accounted for as a liability. Other income (expense), net for the year ended December 31, 2013 also included a gain of $1,366 from the sale of research and development property and equipment sold subsequent to the workforce reduction that occurred in October 2013. See Note 4, Property and Equipment, Net, for further discussion.
	Basic and Diluted Net Loss Per Share
	Basic and diluted net loss per share attributable to common stockholders is calculated based on the weighted average number of common shares outstanding during the period. Diluted net loss per share gives effect to the dilutive potential of common stock consisting of stock options, common stock warrants, and unvested restricted stock units ("RSUs").
	Weighted average potential shares of common stock of 24,628,775, 6,773,394, and 5,574,915 were excluded from the calculation of diluted net loss per share for the years ended December 31, 2014, 2013 and 2012, respectively, as inclusion of the potential shares would have had an anti-dilutive effect on the net loss per share for the periods. The increase in the weighted average potential shares of common stock excluded from the calculation of diluted net loss per share increased from the prior year due to the issuance of warrants under the two financing transactions that occurred during the year ended December 31, 2014. See Note 6, Stockholders' Equity, for further discussion. At December 31, 2014, the Company had outstanding 140,325,643 shares of common stock.
	Comprehensive Loss
	For all periods presented, there were no differences between net loss and comprehensive loss.
	Discontinued Operations
	Effective September 30, 2012, the Company entered into an asset purchase agreement (the "FARESTON® Purchase Agreement") with Strakan International S.á r.l., an affiliate of ProStrakan Group plc ("ProStrakan") pursuant to which the Company agreed to transfer, sell and assign to ProStrakan all of the Company's rights and certain assets related to FARESTON® for a total cash purchase price of $21,671. The Company recognized a gain of $18,831 on the sale of FARESTON® for the year ended December 31, 2012. The gain represents the gross proceeds received from the sale reduced by a contract termination fee of $1,000 due to Orion (as discussed further in Note 7, Collaboration and License Agreements), a financial advisory fee related to the transaction of $1,712, and other transaction expenses of approximately $128. The Company has accounted for FARESTON® as a discontinued operation. As a result, revenue of $5,284, cost of goods sold of $784, and operating expenses of $655 related to FARESTON® were excluded from the respective captions in the statement of operations and were included in discontinued operations for the years ended December 31, 2012. Under the FARESTON® Purchase Agreement, the Company remains liable for future product returns relating to sales of FARESTON® made by the Company prior to September 30, 2012. For the year ended December 31, 2014, the Company recorded a benefit of $576 as general and administrative expenses in the statement of operations for adjustments to the Company's accrual for product returns related to the closure of the return period for a portion of the previously sold inventory.
	FARESTON® *Revenue Recognition*
	Revenue from product sales of FARESTON®, which is included in income from discontinued operations before income taxes for the year ended December 31, 2012, was recognized less deductions for estimated sales discounts and sales returns. Revenue from product sales was recognized when persuasive evidence of an arrangement existed, title passed, the price was fixed or determinable, and collectability was reasonably assured. The Company accounted for rebates to certain governmental agencies as a reduction of product sales. The Company allows customers to return product within a specified time period prior to and subsequent to the product's labeled expiration date. Although the Company sold its rights and certain assets related to FARESTON® effective September 30, 2012, the Company retains the liability for future product returns relating to sales of FARESTON® made by the Company prior to September 30, 2012. Therefore, the Company estimates an accrual for product returns based on factors which include historical product returns and estimated product in the distribution channel which is expected to exceed its expiration date. At December 31, 2014 and December 31, 2013, the Company's accrual for product returns, was $141 and $918, respectively. Of these amounts, $30 and $332 have been included in "Other long-term liabilities" in the Company's balance sheet at December 31, 2014 and December 31, 2013, respectively, and represents the portion of the Company's product returns accrual estimated to be payable after one year.
	Restructuring
	In October 2013, the Company implemented a reduction in its workforce following the announced results from its two Phase 3 clinical trials evaluating enobosarm 3 mg for the prevention and treatment of muscle wasting in patients with advanced NSCLC. The reduction in force was effective immediately and represented approximately 60% of the Company's total workforce.
	As a result of the workforce reduction, the Company incurred severance related cash expenses of $1,306, of which $351 was included in general and administrative expenses and $955 was included in research and development expenses for the year ended December 31, 2013. All of these expenses were paid as of December 31, 2013. Additionally, the Company recognized a net benefit of approximately $370 resulting from the reversal of share-based compensation expense related to the modification of certain stock option provisions for the severed employees. Of this amount, $81 was included as a benefit to general and administrative expenses and $289 was included as a benefit to research and development expenses for the year ended December 31, 2013.
	As a result of the October 2013 reduction in its workforce, the Company is no longer conducting in-house drug discovery activities. During the fourth quarter of 2013, the Company cancelled its sublease for the laboratory facilities and office space utilized for drug discovery. Additionally, the Company sold its related property and equipment for a gain of $1,366, which was included in other income (expense), net for the year ended December 31, 2013.
	Recent Accounting Pronouncements
	In August 2014, the Financial Accounting Standards Board issued Accounting Standard Update 2014-15, Disclosure of Uncertainties about an Entity's Ability to Continue as a Going Concern. The new guidance is intended to define management's responsibility to evaluate whether there is substantial doubt about an organization's ability to continue as a going concern within one year of the date the financial statements are issued and to provide related footnote disclosure. This new guidance is effective for the first annual period ending after December 15, 2016 and interim periods thereafter.
	Subsequent Events
	The Company has evaluated all events or transactions that occurred after December 31, 2014 up through the date the financial statements were issued. There were no material recognizable or nonrecognizable subsequent events during the period evaluated.

ShareBased_Compensation

Share-Based Compensation	12 Months Ended
Share-Based Compensation	Dec. 31, 2014
Share-Based Compensation
Share-Based Compensation	3. Share-Based Compensation
	Share-based payments include stock option grants and RSUs 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 and continues to grant to employees and non-employees options to purchase common stock under various plans at prices equal to the fair market value of the 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. As described below, however, certain of the Company's outstanding options were modified in 2013 to provide an extended post-termination exercise period. 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-Merton pricing valuation 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. The amount of share-based compensation expense recognized is reduced ratably over the vesting period by an estimate of the percentage of options granted that are expected to be forfeited or canceled before becoming fully vested.
	As part of the October 2013 workforce reduction, the Company modified stock options of the terminated employees to accelerate the vesting of certain outstanding non-vested stock options and to extend the post-termination exercise period of their vested stock options. The terminated employees' stock options were modified to accelerate the vesting of all outstanding and unvested stock options as if an employee had remained in continuous service as an employee of the Company through January 1, 2014. Further, the Company extended the post-termination exercise period of each terminated employee's outstanding and vested options until the earliest to occur of June 1, 2014 or the expiration of the original term of the particular option.
	As part of the Company's efforts to retain the essential employees continuing with the Company following the October 2013 workforce reduction, the Company modified certain stock options held by continuing employees in the fourth quarter of 2013 to accelerate the vesting of certain outstanding non-vested stock options and to extend the post-termination exercise period of vested stock options. For these continuing employees, each of their outstanding stock options was modified to provide that if the employee's service continued through the end of business on May 31, 2014, then: (i) an additional number of shares subject to such option would immediately vest as if the employee's service had continued through January 1, 2015 and (ii) the period during which the vested portion of such options will generally expire would be extended from 90 days to six months after the employee's termination of service, subject in each case to the earlier expiration of the original term of the applicable stock option award.
	Additionally, in the fourth quarter of 2013, the Company granted RSUs to certain of the continuing employees, which RSUs vested in full June 1, 2014. The Company estimated the fair value of RSUs using the closing price of its stock on the grant date. The fair value of the RSUs was amortized on a straight-line basis over the requisite service period of the awards. At December 31, 2013, the Company had 1,225,000 unvested RSUs outstanding with a weighted average grant date fair value per share of $1.87. All of the Company's outstanding RSUs vested during the second quarter of 2014 and no RSUs were outstanding as of December 31, 2014. The number of RSUs vested includes 371,906 shares that were withheld on behalf of the Company's employees to satisfy the statutory tax withholding requirements.
	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, 2014:

			Years Ended December 31,
			2014			2013			2012
	Research and development expenses		$	2,512		$	1,875		$	1,046
	General and administrative expenses			2,041			1,993			1,771

	Total share-based compensation		$	4,553		$	3,868		$	2,817


	Share-based compensation expense recorded in the statement of operations as general and administrative expense for the years ended December 31, 2014, 2013 and 2012 included share-based compensation expense related to deferred compensation arrangements for the Company's non-employee directors of $125, $135 and $169, respectively. See Note 10, Directors' Deferred Compensation Plan, for further discussion of deferred compensation arrangements for the Company's non-employee directors.
	In the second quarter of 2014, in connection with the severance agreement entered into with the Company's then Chief Executive Officer in connection with his resignation, all of the executive's outstanding unvested stock options were vested and became immediately exercisable on April 13, 2014. The Company extended the post-termination exercise period of all of these stock options until the earlier to occur of (i) April 13, 2019 or (ii) the expiration of the term of a particular stock option grant. The Company recorded a one-time, noncash net compensation expense of $215 relating to these stock option modifications.
	As a result of the October 2013 modifications of certain stock options held by terminated employees, the Company recognized a net benefit of approximately $370 resulting from the reversal of previously recognized share-based compensation expense that was in excess of the modified fair value of the options. Of this amount, $81 was included as a benefit to general and administrative expenses and $289 was included as a benefit to research and development expenses for the year ended December 31, 2013. The modifications of certain stock options held by the Company's continuing employees during the year ended December 31, 2013 did not have a material impact on share-based compensation expense recognized during the period.
	Share-based compensation expense recorded as research and development expenses for the year ended December 31, 2012 was reduced by the reversal of previously recognized share-based compensation expense for non-vested stock options that were canceled in conjunction with the resignation of an executive officer during the year.
	For the years ended December 31, 2014, 2013 and 2012, the weighted average grant date fair value per share of stock options granted was $1.04, $2.13 and $2.14, respectively. The weighted average for key assumptions used in determining the grant date fair value of options granted in 2014, 2013 and 2012, and a summary of the methodology applied to develop each assumption is as follows:

			Years Ended December 31,
			2014			2013			2012
	Expected price volatility			86.5%			82.9%			69.6%
	Risk-free interest rate			2.3%			1.27%			1.22%
	Weighted average expected life in years			6.9 years			5.9 years			6.5 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, 2014:

			Number of			Weighted
			Shares			Average
						Exercise Price
						Per Share
	Options outstanding at January 1, 2012			4,945,565		$	9.12
	Options granted			1,141,250			3.35
	Options forfeited or expired			(675,755	)		8.82
	Options exercised			(28,201	)		3.05

	Options outstanding at December 31, 2012			5,382,859			7.96
	Options granted			2,784,200			3.12
	Options forfeited or expired			(1,400,419	)		5.86
	Options exercised			(321,298	)		3.81

	Options outstanding at December 31, 2013			6,445,342			6.58

	Options granted			3,094,500			1.34
	Options forfeited or expired			(1,435,408	)		8.5
	Options exercised			-			-

	Options outstanding at December 31, 2014			8,104,434			4.24


	Options vested and expected to vest at December 31, 2014			7,795,136			4.34


	The following table summarizes information about stock options outstanding at December 31, 2014:

	Options Outstanding										Options Exercisable
Exercise Price		Number		Weighted			Weighted			Number		Weighted
		Outstanding		Average			Average			Exercisable		Average
				Remaining			Exercise					Exercise
				Contractual			Price					Price
				Life (years)
$0.61 - $1.56		3,038,000			9.41		$	1.34		100		$	1.51
$1.88 - $4.20		3,697,200			6.55			3.11		3,037,803			2.97
$4.44 - $20.40		1,369,234			3.05			13.72		1,314,702			14.09

		8,104,434			7.03			4.24		4,352,605			6.33


At December 31, 2014, the aggregate intrinsic value of all outstanding options was $5 with a weighted average remaining contractual term of 7.03 years. Of the Company's outstanding options, 4,352,605 options were exercisable and had a weighted average remaining contractual term of 5.28 years and no aggregate intrinsic value. Additionally, the Company's vested and expected to vest options had a weighted average remaining contractual term of 6.94 years and an aggregate intrinsic value of $4.
There were no options exercised during the year ended December 31, 2014. The total intrinsic value of options exercised during the years ended December 31, 2013 and 2012 was $688 and $36, respectively. At December 31, 2014, the total compensation cost related to non-vested options not yet recognized was $4,030, with a weighted average expense recognition period of 3.94 years. Shares available for future issuance under the Company's stock option and equity incentive plans were 4,979,673 at December 31, 2014. On January 1, 2015, shares available for future issuance under the 2013 equity incentive plan and 2013 non-employee director equity incentive plan increased by an aggregate of 6,113,026 shares in accordance with the automatic increase provisions of such plans.

Property_and_Equipment_Net

Property and Equipment, Net	12 Months Ended
Property and Equipment, Net	Dec. 31, 2014
Property and Equipment, Net
Property and Equipment, Net	4. Property and Equipment, Net
	Property and equipment, net consisted of the following:

		December 31,
		2014			2013
	Computer equipment and software	$	2,128		$	2,130
	Furniture and fixtures		1,032			1,032
	Leasehold improvements		355			355
	Office and laboratory equipment		261			261

			3,776			3,778
	Less: accumulated depreciation		(3,747	)		(3,666	)

		$	29		$	112


	Depreciation and amortization expense for the years ended December 31, 2014, 2013 and 2012 was $88, $369 and $730, respectively. Of these amounts, $1, $169 and $290, respectively, were included in research and development expenses in the statements of operations.
	Subsequent to the reduction in workforce implemented in October 2013 and the Company's determination to cease drug discovery activities, the Company sold its related property and equipment and recognized a gain of $1,366 during the year ended December 31, 2013. The carrying value associated with the property and equipment that was sold was $58 and related to laboratory equipment.

Accrued_Expenses_and_Other_Cur

Accrued Expenses and Other Current Liabilities	12 Months Ended
Accrued Expenses and Other Current Liabilities	Dec. 31, 2014
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,
		2014		2013
	Clinical trials	$	929	$	1,127
	Net deferred income tax liabilities		319		156
	General and administrative		267		497
	Employee compensation		160		1,354
	Product returns		112		586
	Research and development		63		39

		$	1,850	$	3,759

Stockholders_Equity

Stockholders' Equity	12 Months Ended
Stockholders' Equity	Dec. 31, 2014
Stockholders' Equity
Stockholders' Equity	6. Stockholders' Equity
	Authorized Capital
	The Company's certificate of incorporation authorizes the Company to issue 200,000,000 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 and Associated Warrant Liability
	On November 14, 2014, the Company completed a private placement of units consisting of an aggregate of 64,311,112 shares of common stock and warrants to purchase an aggregate of 64,311,112 shares of its common stock for net proceeds of $42,814, after deducting offering expenses. The purchasers in the private placement included certain existing GTx stockholders and certain members of the GTx management team and board of directors. 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 the 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 $0.85 and will be exercisable at any time and from time to time from and after the earlier of (i) the date the Company obtains stockholder approval of an amendment to its Restated Certificate of Incorporation to increase its authorized common stock to an amount necessary to effect the share settlement of all of the warrants, which approval the Company has contractually-agreed to seek no later than May 27, 2015, or (ii) the trading day immediately prior to the occurrence of a "fundamental transaction" (as defined in the warrants), but in no event later than June 1, 2015, and will continue to be exercisable for four years thereafter. The Company does not currently have a sufficient number of authorized and unreserved shares of common stock necessary to settle exercises of all of the warrants in full in shares of common stock; accordingly, the warrants will be subject to net cash settlement if, at the time of any exercise, there are then an insufficient number of authorized and reserved shares of common stock to effect a share settlement of the warrants. Assuming stockholder approval of an amendment to the Company's Restated Certificate of Incorporation to increase its authorized common stock to an amount necessary to effect the share settlement of all of the warrants is obtained, warrant exercises would no longer be subject to net cash settlement. The warrants also contain certain terms that could require 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 pricing valuation 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 $0.125 per unexercised share underlying each warrant. Due to these provisions, the Company is required to account for these warrants as a liability at fair value using the Black-Scholes-Merton pricing valuation model and the estimated warrant liability is required to be revalued at each balance sheet date until the earlier of the exercise of the warrants or, assuming stockholder approval is obtained for the authorization of additional common stock, the expiration of the provision on December 31, 2016 that could require cash settlement upon certain change of control transactions. The Company's warrant liability is influenced by several factors including the price of the Company's common stock as of the balance sheet date.
	At issuance, the fair value of the warrant liability was estimated to be $21,626. These warrants were revalued at fair value as of December 31, 2014 and the resulting increase in fair value of $8,804 was recorded as a non-cash loss on the change in fair value of warrant liability in the Company's statement of operations. The fair value of the warrants at December 31, 2014 of $30,430 was estimated using the Black-Scholes-Merton pricing valuation model with the following assumptions: expected volatility of 91%, risk-free interest rate of 1.5%, expected life of approximately 4.5 years and no dividends. Significant changes to the Company's market price for its common stock will impact the implied and/or historical volatility used to fair value the warrants. Any significant increases in the Company's stock price will likely create an increase to the fair value of the warrant liability. Similarly, any significant decreases in the Company's stock price will likely create a decrease to the fair value of the warrant liability.
	On March 6, 2014, the Company completed a private placement of units consisting of an aggregate of 11,976,048 shares of common stock and warrants to purchase an aggregate of 10,179,642 shares of its common stock for net proceeds of $21,135, after deducting offering expenses. The net proceeds from the private placement were allocated to the common stock and warrants based upon their relative fair values. The warrants, which had a one year term that expired on March 6, 2015, carried a per share exercise price of $1.67. 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 met the scope exception for determining whether the instruments require accounting as derivatives and are classified in stockholders' equity. The fair value of the warrants on the date of grant was estimated at $4,478 using the Black-Scholes-Merton pricing valuation model with the following assumptions: expected volatility of 67%, risk free interest rate of 0.12%, expected life of one year and no dividends. All of these warrants expired unexercised on March 6, 2015.

Collaboration_and_License_Agre

Collaboration and License Agreements	12 Months Ended
Collaboration and License Agreements	Dec. 31, 2014
Collaboration and License Agreements
Collaboration and License Agreements	7. Collaboration and License Agreements
	University of Tennessee Research Foundation License Agreement
	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.
	Former Orion Corporation License and Supply Agreement
	In connection with the Company's sale of its rights and certain assets related to FARESTON® to ProStrakan, the Company and Orion agreed to terminate the Amended and Restated License and Supply Agreement, dated January 1, 2005, as amended, between the Company and Orion (the "Orion Supply Agreement") as well as certain other agreements between the Company and Orion related to the Orion Supply Agreement (collectively, the "Orion Agreements"). Pursuant to the Orion Supply Agreement, the Company obtained an exclusive license from Orion to develop and commercialize toremifene-based products for all human indications worldwide, except breast cancer outside of the United States, and Orion agreed to manufacture and supply all of the Company's needs for clinical trial and commercial grade material for toremifene-based products developed and marketed in the United States and abroad, including toremifene globally and FARESTON® in the United States. The termination of the Orion Agreements was effective September 30, 2012. As consideration for Orion's agreement to terminate the Orion Agreements and to enter into certain agreements with ProStrakan to effect the FARESTON® sale, the Company paid Orion $1,000 in October 2012.

Intangible_Assets_Net

Intangible Assets, Net	12 Months Ended
Intangible Assets, Net	Dec. 31, 2014
Intangible Assets, Net
Intangible Assets, Net	8. Intangible Assets, Net
	In accordance with the terms of the former Orion Supply Agreement, the Company paid a license fee to Orion of $4,826. 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.
	The Company's remaining intangible asset, net at December 31, 2014 and 2013 was $152 and $166, respectively, related to the SARM License Agreement.

Income_Taxes

Income Taxes	12 Months Ended
Income Taxes	Dec. 31, 2014
Income Taxes
Income Taxes	9. Income Taxes
	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,
		2014			2013
	Deferred income tax assets:
	Net federal and state operating loss carryforwards	$	139,126		$	127,819
	Research and development credits		12,754			11,934
	Share-based compensation		6,800			8,670
	Depreciation and amortization		89			170
	Other		69			425

	Total deferred tax assets		158,838			149,018

	Deferred income tax liabilities:
	Other		329			157

	Total deferred tax liabilities		329			157

	Net deferred tax assets		158,509			148,861
	Valuation allowance		(158,509	)		(148,861	)

		$	-		$	-


	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 $9,648, $17,318 and $8,836 in 2014, 2013, and 2012, respectively.
	At December 31, 2014, the Company had net federal operating loss carryforwards of approximately $358,702, which expire from 2018 to 2034 if not utilized. The Company had state operating loss carryforwards of approximately $337,735, which expire from 2015 to 2034 if not utilized. The Company also had research and development credits at December 31, 2014 of approximately $12,754, which expire from 2020 to 2034 if not utilized.
	Both of the net federal and state operating loss carryforwards include approximately $2,301 of deductions related to the exercise of stock options. This amount represents an excess tax benefit and has not been included in the gross deferred income tax asset reflected for net federal and state operating loss carryforwards. If utilized, the benefits from these deductions will be recorded as an adjustment to additional paid in capital.
	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, 2014, 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, 2014 to determine whether such amounts are likely to be limited by Section 382. As a result of this study, the Company does not currently believe any Section 382 limitation exists through December 31, 2014. 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 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
Directors' Deferred Compensation Plan	Dec. 31, 2014
Directors' Deferred Compensation Plan
Directors' Deferred Compensation Plan	10. 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, 2014, 2013 and 2012, the Company incurred non-employee director fee expense of $247, $259 and $237, respectively, of which $125, $135 and $169 was deferred into stock accounts and will be paid in common stock following separation from service as a director. At December 31, 2014, 237,100 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.

401k_Plan

401(k) Plan	12 Months Ended
401(k) Plan	Dec. 31, 2014
401(k) Plan
401(k) Plan	11. 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 $17.5 for employees under age 50 and $23 for employees 50 and older in calendar year 2014. 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 $200, $338 and $363 in 2014, 2013 and 2012, respectively.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Dec. 31, 2014
Commitments and Contingencies
Commitments and Contingencies	12. Commitments and Contingencies
	Operating Lease Commitments
	The Company previously leased laboratory facilities and office space pursuant to a sublease, which had been accounted for as an operating lease. Subsequent to the reduction in force implemented in October 2013, this lease was cancelled effective December 31, 2013. The Company subleases office space under a sublease that is accounted for as an operating lease. This sublease has escalating rent payments and expires on April 30, 2015. Total rent expense under the operating leases was approximately $513, $674 and $963 for the years ended December 31, 2014, 2013 and 2012, respectively. As of December 31, 2014, future annual minimum payments under operating lease arrangements were $184 for the year ended December 31, 2015.

Quarterly_Financial_Data_Unaud

Quarterly Financial Data (Unaudited)	12 Months Ended
Quarterly Financial Data (Unaudited)	Dec. 31, 2014
Quarterly Financial Data (Unaudited)
Quarterly Financial Data (Unaudited)	13. Quarterly Financial Data (Unaudited)
	The following is a summary of the quarterly results of operations for the years ended December 31, 2014 and 2013:

			2014 Quarters Ended
			March 31			June 30			September 30			December 31
	Expenses:
	Research and development expenses		$	6,360		$	7,894		$	3,362		$	3,254
	General and administrative expenses			2,629			3,052			1,594			2,203

	Total expenses			8,989			10,946			4,956			5,457

	Loss from operations			(8,989	)		(10,946	)		(4,956	)		(5,457	)
	Other income (expense), net			2			2			21			(284	)
	Loss on change in fair value of warrant liability (a)			-			-			-			(8,804	)

	Net loss		$	(8,987	)	$	(10,944	)	$	(4,935	)	$	(14,545	)


	Net loss per share — basic and diluted		$	(0.14	)	$	(0.15	)	$	(0.06	)	$	(0.13	)



	Weighted average shares outstanding:
	Basic and diluted			66,512,069			75,433,302			76,014,531			108,869,121



	(a)	The loss on change in fair value of warrant liability is related to the private placement of warrants completed in November 2014. See Note 6, Stockholders' Equity, for further information.


			2013 Quarters Ended
			March 31			June 30			September 30			December 31
	Expenses:
	Research and development expenses		$	9,614		$	10,139		$	6,477		$	6,088
	General and administrative expenses			3,023			2,684			2,483			3,091

	Total expenses			12,637			12,823			8,960			9,179

	Loss from operations			(12,637	)		(12,823	)		(8,960	)		(9,179	)
	Other income, net			55			21			23			1,389

	Net loss		$	(12,582	)	$	(12,802	)	$	(8,937	)	$	(7,790	)


	Net loss per share — basic and diluted		$	(0.20	)	$	(0.20	)	$	(0.14	)	$	(0.12	)



	Weighted average shares outstanding:
	Basic and diluted			62,864,140			62,994,771			63,179,394			63,185,389

Significant_Accounting_Policie1

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
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, 2014 and 2013, 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:

		Laboratory and 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
	On November 14, 2014, the Company issued warrants to purchase 64,311,112 shares of its common stock. The Company classifies the warrants as a liability on its balance sheet since the warrants contain certain terms that could require 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 option pricing formula) 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 $0.125 per unexercised share underlying each warrant. In addition, each warrant is subject to net cash settlement if, at the time of any exercise, there are then an insufficient number of authorized and reserved shares of common stock to effect a share settlement of the warrant. As of December 31, 2014, the Company did not have a sufficient number of authorized and reserved shares of common stock to effect the share settlement of all of these warrants; however, these warrants were not exercisable at December 31, 2014.
	As a result of the foregoing provisions, the Company is required to account for these warrants as a liability at fair value and the estimated warrant liability is required to be revalued at each balance sheet date until the earlier of the exercise of the warrants or, assuming stockholder approval is obtained for the authorization of additional common stock, the expiration of the provision on December 31, 2016 that could require cash settlement upon certain change of control transactions. Upon the exercise of the warrants or, assuming stockholder approval is obtained for the authorization of additional common stock, the expiration of the provision on December 31, 2016 that could require cash settlement upon certain change of control transactions, the fair value of the warrants will be reclassified from a liability to stockholders' equity on the Company's balance sheets and no further adjustment to the fair value would be made in subsequent periods. See Note 6, Stockholders' Equity, for further information regarding these warrants and the Company's valuation of the warrant liability.

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 warrant liability approximate their fair values. The fair value of the warrant liability is estimated using the Black-Scholes-Merton pricing valuation 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
	Asset and liabilities measured at fair value on a recurring basis as of December 31, 2014 included only the Company's warrant liability of $30,430, which was classified within Level 3 of the hierarchy. As of December 31, 2013, the Company had no assets or liabilities measured at fair value on a recurring basis within Level 3 of the hierarchy. A loss of $8,804 related to the change in the fair value of the warrant liability was recognized during the year ended December 31, 2014 as a non-cash loss in the Company's statement of operations.
	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, 2014 and December 31, 2013, net of the valuation allowance, the net deferred tax assets were reduced to zero. See Note 9, Income Taxes, for further discussion.
	The Company has recognized the tax effect of discontinued operations in the statement of operations for the year ended December 31, 2012 in accordance with the intra-period accounting rules. An offsetting tax benefit was recorded in continuing operations for the year ended December 31, 2012 in relation to the tax expense that was recognized for discontinued operations.

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 foreign currency transaction gains and losses, interest earned on the Company's cash, cash equivalents and short-term investments, interest expense, and other non-operating income or expense. Other income (expense), net for the year ended December 31, 2014 also included expenses related to the private placement of common stock and warrants completed in November 2014 as the warrants issued were accounted for as a liability. Other income (expense), net for the year ended December 31, 2013 also included a gain of $1,366 from the sale of research and development property and equipment sold subsequent to the workforce reduction that occurred in October 2013. See Note 4, Property and Equipment, Net, for further discussion.

Basic and Diluted Net Loss Per Share	Basic and Diluted Net Loss Per Share
	Basic and diluted net loss per share attributable to common stockholders is calculated based on the weighted average number of common shares outstanding during the period. Diluted net loss per share gives effect to the dilutive potential of common stock consisting of stock options, common stock warrants, and unvested restricted stock units ("RSUs").
	Weighted average potential shares of common stock of 24,628,775, 6,773,394, and 5,574,915 were excluded from the calculation of diluted net loss per share for the years ended December 31, 2014, 2013 and 2012, respectively, as inclusion of the potential shares would have had an anti-dilutive effect on the net loss per share for the periods. The increase in the weighted average potential shares of common stock excluded from the calculation of diluted net loss per share increased from the prior year due to the issuance of warrants under the two financing transactions that occurred during the year ended December 31, 2014. See Note 6, Stockholders' Equity, for further discussion. At December 31, 2014, the Company had outstanding 140,325,643 shares of common stock.

Comprehensive Loss	Comprehensive Loss
	For all periods presented, there were no differences between net loss and comprehensive loss.

Discontinued Operations	Discontinued Operations
	Effective September 30, 2012, the Company entered into an asset purchase agreement (the "FARESTON® Purchase Agreement") with Strakan International S.á r.l., an affiliate of ProStrakan Group plc ("ProStrakan") pursuant to which the Company agreed to transfer, sell and assign to ProStrakan all of the Company's rights and certain assets related to FARESTON® for a total cash purchase price of $21,671. The Company recognized a gain of $18,831 on the sale of FARESTON® for the year ended December 31, 2012. The gain represents the gross proceeds received from the sale reduced by a contract termination fee of $1,000 due to Orion (as discussed further in Note 7, Collaboration and License Agreements), a financial advisory fee related to the transaction of $1,712, and other transaction expenses of approximately $128. The Company has accounted for FARESTON® as a discontinued operation. As a result, revenue of $5,284, cost of goods sold of $784, and operating expenses of $655 related to FARESTON® were excluded from the respective captions in the statement of operations and were included in discontinued operations for the years ended December 31, 2012. Under the FARESTON® Purchase Agreement, the Company remains liable for future product returns relating to sales of FARESTON® made by the Company prior to September 30, 2012. For the year ended December 31, 2014, the Company recorded a benefit of $576 as general and administrative expenses in the statement of operations for adjustments to the Company's accrual for product returns related to the closure of the return period for a portion of the previously sold inventory.

FARESTON Revenue Recognition	FARESTON® *Revenue Recognition*
	Revenue from product sales of FARESTON®, which is included in income from discontinued operations before income taxes for the year ended December 31, 2012, was recognized less deductions for estimated sales discounts and sales returns. Revenue from product sales was recognized when persuasive evidence of an arrangement existed, title passed, the price was fixed or determinable, and collectability was reasonably assured. The Company accounted for rebates to certain governmental agencies as a reduction of product sales. The Company allows customers to return product within a specified time period prior to and subsequent to the product's labeled expiration date. Although the Company sold its rights and certain assets related to FARESTON® effective September 30, 2012, the Company retains the liability for future product returns relating to sales of FARESTON® made by the Company prior to September 30, 2012. Therefore, the Company estimates an accrual for product returns based on factors which include historical product returns and estimated product in the distribution channel which is expected to exceed its expiration date. At December 31, 2014 and December 31, 2013, the Company's accrual for product returns, was $141 and $918, respectively. Of these amounts, $30 and $332 have been included in "Other long-term liabilities" in the Company's balance sheet at December 31, 2014 and December 31, 2013, respectively, and represents the portion of the Company's product returns accrual estimated to be payable after one year.

Restructuring	Restructuring
	In October 2013, the Company implemented a reduction in its workforce following the announced results from its two Phase 3 clinical trials evaluating enobosarm 3 mg for the prevention and treatment of muscle wasting in patients with advanced NSCLC. The reduction in force was effective immediately and represented approximately 60% of the Company's total workforce.
	As a result of the workforce reduction, the Company incurred severance related cash expenses of $1,306, of which $351 was included in general and administrative expenses and $955 was included in research and development expenses for the year ended December 31, 2013. All of these expenses were paid as of December 31, 2013. Additionally, the Company recognized a net benefit of approximately $370 resulting from the reversal of share-based compensation expense related to the modification of certain stock option provisions for the severed employees. Of this amount, $81 was included as a benefit to general and administrative expenses and $289 was included as a benefit to research and development expenses for the year ended December 31, 2013.
	As a result of the October 2013 reduction in its workforce, the Company is no longer conducting in-house drug discovery activities. During the fourth quarter of 2013, the Company cancelled its sublease for the laboratory facilities and office space utilized for drug discovery. Additionally, the Company sold its related property and equipment for a gain of $1,366, which was included in other income (expense), net for the year ended December 31, 2013.

Recent Accounting Pronouncements	Recent Accounting Pronouncements
	In August 2014, the Financial Accounting Standards Board issued Accounting Standard Update 2014-15, Disclosure of Uncertainties about an Entity's Ability to Continue as a Going Concern. The new guidance is intended to define management's responsibility to evaluate whether there is substantial doubt about an organization's ability to continue as a going concern within one year of the date the financial statements are issued and to provide related footnote disclosure. This new guidance is effective for the first annual period ending after December 15, 2016 and interim periods thereafter.

Subsequent Events	Subsequent Events
	The Company has evaluated all events or transactions that occurred after December 31, 2014 up through the date the financial statements were issued. There were no material recognizable or nonrecognizable subsequent events during the period evaluated.

Significant_Accounting_Policie2

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2014
Significant Accounting Policies
Schedule of estimated useful lives of property and equipment

		Laboratory and office equipment	3 to 5 years

		Leasehold improvements	3 to 7 years

		Furniture and fixtures	5 years

		Computer equipment and software	3 years

ShareBased_Compensation_Tables

Share-Based Compensation (Tables)	12 Months Ended
Share-Based Compensation (Tables)	Dec. 31, 2014
Share-Based Compensation
Summary of share-based compensation expense

		Years Ended December 31,
		2014			2013			2012
	Research and development expenses	$	2,512		$	1,875		$	1,046
	General and administrative expenses		2,041			1,993			1,771

	Total share-based compensation	$	4,553		$	3,868		$	2,817




Schedule of assumptions used to estimate fair value of options

		Years Ended December 31,
		2014			2013			2012
	Expected price volatility		86.5%			82.9%			69.6%
	Risk-free interest rate		2.3%			1.27%			1.22%
	Weighted average expected life in years		6.9 years			5.9 years			6.5 years
	Dividend yield		0%			0%			0%


Summary of stock option transactions

		Number of			Weighted
		Shares			Average
					Exercise Price
					Per Share
	Options outstanding at January 1, 2012		4,945,565		$	9.12
	Options granted		1,141,250			3.35
	Options forfeited or expired		(675,755	)		8.82
	Options exercised		(28,201	)		3.05

	Options outstanding at December 31, 2012		5,382,859			7.96
	Options granted		2,784,200			3.12
	Options forfeited or expired		(1,400,419	)		5.86
	Options exercised		(321,298	)		3.81

	Options outstanding at December 31, 2013		6,445,342			6.58

	Options granted		3,094,500			1.34
	Options forfeited or expired		(1,435,408	)		8.5
	Options exercised		-			-

	Options outstanding at December 31, 2014		8,104,434			4.24


	Options vested and expected to vest at December 31, 2014		7,795,136			4.34




Schedule of stock option activity by exercise price range	:

	Options Outstanding									Options Exercisable
	Exercise Price	Number		Weighted			Weighted			Number	Weighted
		Outstanding		Average			Average			Exercisable	Average
				Remaining			Exercise				Exercise
				Contractual			Price				Price
				Life (years)
	$0.61 - $1.56	3,038,000			9.41		$	1.34		100	$	1.51
	$1.88 - $4.20	3,697,200			6.55			3.11		3,037,803		2.97
	$4.44 - $20.40	1,369,234			3.05			13.72		1,314,702		14.09

		8,104,434			7.03			4.24		4,352,605		6.33

Property_and_Equipment_Net_Tab

Property and Equipment, Net (Tables)	12 Months Ended
Property and Equipment, Net (Tables)	Dec. 31, 2014
Property and Equipment, Net
Schedule of property and equipment, net

		December 31,
		2014			2013
	Computer equipment and software	$	2,128		$	2,130
	Furniture and fixtures		1,032			1,032
	Leasehold improvements		355			355
	Office and laboratory equipment		261			261

			3,776			3,778
	Less: accumulated depreciation		(3,747	)		(3,666	)

		$	29		$	112

Accrued_Expenses_and_Other_Cur1

Accrued Expenses and Other Current Liabilities (Tables)	12 Months Ended
Accrued Expenses and Other Current Liabilities (Tables)	Dec. 31, 2014
Accrued Expenses and Other Current Liabilities
Schedule of accrued expenses and other current liabilities

		December 31,
		2014		2013
	Clinical trials	$	929	$	1,127
	Net deferred income tax liabilities		319		156
	General and administrative		267		497
	Employee compensation		160		1,354
	Product returns		112		586
	Research and development		63		39

		$	1,850	$	3,759

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
Income Taxes (Tables)	Dec. 31, 2014
Income Taxes
Schedule of principal components of the Company's net deferred income tax assets and liabilities

		December 31,
		2014			2013
	Deferred income tax assets:
	Net federal and state operating loss carryforwards	$	139,126		$	127,819
	Research and development credits		12,754			11,934
	Share-based compensation		6,800			8,670
	Depreciation and amortization		89			170
	Other		69			425

	Total deferred tax assets		158,838			149,018

	Deferred income tax liabilities:
	Other		329			157

	Total deferred tax liabilities		329			157

	Net deferred tax assets		158,509			148,861
	Valuation allowance		(158,509	)		(148,861	)

		$	-		$	-

Quarterly_Financial_Data_Unaud1

Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
Quarterly Financial Data (Unaudited) (Tables)	Dec. 31, 2014
Quarterly Financial Data (Unaudited)
Summary of the quarterly results of operations

			2014 Quarters Ended
			March 31			June 30			September 30			December 31
	Expenses:
	Research and development expenses		$	6,360		$	7,894		$	3,362		$	3,254
	General and administrative expenses			2,629			3,052			1,594			2,203

	Total expenses			8,989			10,946			4,956			5,457

	Loss from operations			(8,989	)		(10,946	)		(4,956	)		(5,457	)
	Other income (expense), net			2			2			21			(284	)
	Loss on change in fair value of warrant liability (a)			-			-			-			(8,804	)

	Net loss		$	(8,987	)	$	(10,944	)	$	(4,935	)	$	(14,545	)


	Net loss per share — basic and diluted		$	(0.14	)	$	(0.15	)	$	(0.06	)	$	(0.13	)



	Weighted average shares outstanding:
	Basic and diluted			66,512,069			75,433,302			76,014,531			108,869,121



	(a)	The loss on change in fair value of warrant liability is related to the private placement of warrants completed in November 2014. See Note 6, Stockholders' Equity, for further information.


			2013 Quarters Ended
			March 31			June 30			September 30			December 31
	Expenses:
	Research and development expenses		$	9,614		$	10,139		$	6,477		$	6,088
	General and administrative expenses			3,023			2,684			2,483			3,091

	Total expenses			12,637			12,823			8,960			9,179

	Loss from operations			(12,637	)		(12,823	)		(8,960	)		(9,179	)
	Other income, net			55			21			23			1,389

	Net loss		$	(12,582	)	$	(12,802	)	$	(8,937	)	$	(7,790	)


	Net loss per share — basic and diluted		$	(0.20	)	$	(0.20	)	$	(0.14	)	$	(0.12	)



	Weighted average shares outstanding:
	Basic and diluted			62,864,140			62,994,771			63,179,394			63,185,389

Significant_Accounting_Policie3

Significant Accounting Policies (Details)	12 Months Ended
	Dec. 31, 2014
	item
Significant Accounting Policies
Number of business segments	1
Laboratory and Office Equipment \| Minimum
Property and equipment
Estimated useful lives	3 years
Laboratory and 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_Policie4

Significant Accounting Policies (Details 2) (USD $)	3 Months Ended	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2014	Nov. 14, 2014	Dec. 31, 2013
Fair Value of Financial Instruments
Warrant liability	$30,430	$30,430
Loss on change in fair value of warrant liability	8,804	8,804
Warrant Liability
Warrants issued to purchase shares under private placement			64,311,112
Maximum contingent per share cash settlement price (in dollars per share)			$0.13
Fair Value Measurements, Recurring \| Level 3
Fair Value of Financial Instruments
Warrant liability	30,430	30,430
Assets at fair value				0
Liabilities at fair value				$0

Significant_Accounting_Policie5

Significant Accounting Policies (Details 3) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Taxes
Net deferred tax assets	$0	$0
Other Income (Expense), Net
Gain on sale of property and equipment		$1,366
Basic and Diluted Net Loss Per Share
Weighted average potential shares of common stock excluded from calculation of diluted net loss per share	24,628,775	6,773,394	5,574,915
Common stock, shares outstanding	140,325,643	63,185,389

Significant_Accounting_Policie6

Significant Accounting Policies (Details 4) (USD $)	3 Months Ended								12 Months Ended			1 Months Ended	0 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Oct. 31, 2012	Sep. 30, 2012
Discontinued Operations disclosures
Gain on sale of FARESTON											$18,831
Operating income disclosures related to discontinued operations
General and administrative expense (benefit)	2,203	1,594	3,052	2,629	3,091	2,483	2,684	3,023	9,478	11,281	10,845
Former Orion Corporation License and Supply Agreement
Discontinued Operations disclosures
Contract termination fee												1,000
Fareston
Discontinued Operations disclosures
Proceeds from the sale of rights and certain assets related to FARESTON													21,671
Gain on sale of FARESTON											18,831
Financial advisory fee											1,712
Other transaction expenses											128
Operating income disclosures related to discontinued operations
Product sales, net											5,284
Cost of product sales											784
Operating expenses											655
General and administrative expense (benefit)									-576
FARESTON Revenue Recognition
Accrual for product returns	141				918				141	918
Accrual for product returns included in other long term liabilities	30				332				30	332
Fareston \| Former Orion Corporation License and Supply Agreement
Discontinued Operations disclosures
Contract termination fee												$1,000

Significant_Accounting_Policie7

Significant Accounting Policies (Details 5) (USD $)	1 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Oct. 31, 2013	Dec. 31, 2013
Restructuring
Reduction in workforce (as a percent)	60.00%
Gain on sale of property and equipment		$1,366
One-time compensation expense related to cash severance
Restructuring
Expense (benefit) related to workforce reduction		1,306
One-time compensation expense related to cash severance \| General and Administrative Expenses
Restructuring
Expense (benefit) related to workforce reduction		351
One-time compensation expense related to cash severance \| Research and Development Expenses
Restructuring
Expense (benefit) related to workforce reduction		955
One-time share based compensation benefit related to amendment of stock option provisions
Restructuring
Expense (benefit) related to workforce reduction		-370
One-time share based compensation benefit related to amendment of stock option provisions \| General and Administrative Expenses
Restructuring
Expense (benefit) related to workforce reduction		-81
One-time share based compensation benefit related to amendment of stock option provisions \| Research and Development Expenses
Restructuring
Expense (benefit) related to workforce reduction		($289)

ShareBased_Compensation_Detail

Share-Based Compensation (Details) (USD $)	12 Months Ended			3 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2014
Share-based compensation expense
Term of options from the grant date	10 years
Total share-based compensation	$4,553	$3,868	$2,817
Share-based compensation expense related to deferred compensation arrangements for non-employee directors	125	135	169
One-time share based compensation benefit related to amendment of stock option provisions
Share-based compensation expense
Expense (benefit) related to workforce reduction		-370
Research and Development Expenses
Share-based compensation expense
Total share-based compensation	2,512	1,875	1,046
Research and Development Expenses \| One-time share based compensation benefit related to amendment of stock option provisions
Share-based compensation expense
Expense (benefit) related to workforce reduction		-289
General and Administrative Expenses
Share-based compensation expense
Total share-based compensation	2,041	1,993	1,771
General and Administrative Expenses \| One-time share based compensation benefit related to amendment of stock option provisions
Share-based compensation expense
Expense (benefit) related to workforce reduction		-81
Maximum
Share-based compensation expense
Term of options from the grant date	10 years
Director
Share-based compensation expense
Option vesting period	3 years
Share-based compensation expense related to deferred compensation arrangements for non-employee directors	125	135	169
Director \| General and Administrative Expenses
Share-based compensation expense
Share-based compensation expense related to deferred compensation arrangements for non-employee directors	125	135	169
Former Chief Executive Officer
Share-based compensation expense
One-time, noncash net compensation expense related to the modification of stock options				$215
Employees
Share-based compensation expense
Period available to exercise all vested options after end of employment relationship	3 months
Option vesting period after employee's termination of service before modification	90 days
Modified option vesting period after employee's termination of service	6 months
Employees \| Maximum
Share-based compensation expense
Option vesting period	5 years

ShareBased_Compensation_Detail1

Share-Based Compensation (Details 2) (Restricted Stock Units (RSUs), USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Restricted Stock Units (RSUs)
Number of Shares
Unvested awards outstanding (in shares)	0	1,225,000
Vested shares withheld to satisfy statutory tax withholding requirements	371,906
Weighted Average Grant Date Fair Value Per Share
Weighted average grant date fair value per share (in dollars per share)		$1.87

ShareBased_Compensation_Detail2

Share-Based Compensation (Details 3) (USD $)	12 Months Ended
Share-Based Compensation (Details 3) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based compensation
Weighted average grant date fair value (in dollars per share)	$1.04	$2.13	$2.14
Fair value of options granted
Expected price volatility (as a percent)	86.50%	82.90%	69.60%
Risk-free interest rate (as a percent)	2.30%	1.27%	1.22%
Weighted average expected life in years	6 years 10 months 24 days	5 years 10 months 24 days	6 years 6 months
Dividend yield (as a percent)	0.00%	0.00%	0.00%
Option term	10 years
Number of Shares
Options outstanding at the beginning of the period (in shares)	6,445,342	5,382,859	4,945,565
Options granted (in shares)	3,094,500	2,784,200	1,141,250
Options forfeited or expired (in shares)	-1,435,408	-1,400,419	-675,755
Options exercised (in shares)	0	-321,298	-28,201
Options outstanding at the end of the period (in shares)	8,104,434	6,445,342	5,382,859
Options vested and expected to vest at the end of the period (in shares)	7,795,136
Weighted Average Exercise Price Per Share
Options outstanding at the beginning of the period (in dollars per share)	$6.58	$7.96	$9.12
Options granted (in dollars per share)	$1.34	$3.12	$3.35
Options forfeited or expired (in dollars per share)	$8.50	$5.86	$8.82
Options exercised (in dollars per share)		$3.81	$3.05
Options outstanding at the end of the period (in dollars per share)	$4.24	$6.58	$7.96
Options vested and expected to vest at the end of the period (in dollars per share)	$4.34
Maximum
Fair value of options granted
Option term	10 years

ShareBased_Compensation_Detail3

Share-Based Compensation (Details 4) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Information about stock options outstanding
Options Outstanding, Number Outstanding (in shares)	8,104,434
Options Outstanding, Weighted Average Remaining Contractual Life	7 years 11 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$4.24
Options Exercisable, Number Exercisable (in shares)	4,352,605
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$6.33
Additional information
Aggregate intrinsic value of all outstanding options (in dollars)	$5
Options exercisable, weighted average remaining contractual term	5 years 3 months 11 days
Options exercisable, aggregate intrinsic value (in dollars)	0
Vested and expected to vest options, weighted average remaining contractual term	6 years 11 months 9 days
Vested and expected to vest options, intrinsic value (in dollars)	4
Options exercised (in shares)	0	321,298	28,201
Intrinsic value of options exercised (in dollars)		688	36
Compensation cost related to non-vested options not yet recognized	$4,030
Weighted average expense recognition period related to non-vested options not yet recognized	3 years 11 months 9 days
Shares available for future issuance under the Company's stock option and equity incentive plans	4,979,673
Increase to shares available for future issuance in accordance with annual automatic increase provisions	6,113,026
$0.61 to $1.56
Information about stock options outstanding
Low end of range of exercise prices (in dollars per share)	$0.61
High end of range of exercise prices (in dollars per share)	$1.56
Options Outstanding, Number Outstanding (in shares)	3,038,000
Options Outstanding, Weighted Average Remaining Contractual Life	9 years 4 months 28 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$1.34
Options Exercisable, Number Exercisable (in shares)	100
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$1.51
$1.88 to $4.20
Information about stock options outstanding
Low end of range of exercise prices (in dollars per share)	$1.88
High end of range of exercise prices (in dollars per share)	$4.20
Options Outstanding, Number Outstanding (in shares)	3,697,200
Options Outstanding, Weighted Average Remaining Contractual Life	6 years 6 months 18 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$3.11
Options Exercisable, Number Exercisable (in shares)	3,037,803
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$2.97
$4.44 to $20.40
Information about stock options outstanding
Low end of range of exercise prices (in dollars per share)	$4.44
High end of range of exercise prices (in dollars per share)	$20.40
Options Outstanding, Number Outstanding (in shares)	1,369,234
Options Outstanding, Weighted Average Remaining Contractual Life	3 years 18 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$13.72
Options Exercisable, Number Exercisable (in shares)	1,314,702
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$14.09

Property_and_Equipment_Net_Det

Property and Equipment, Net (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property and equipment
Property and Equipment, gross	$3,776	$3,778
Less: accumulated depreciation	-3,747	-3,666
Property and Equipment, Net	29	112
Depreciation and amortization expense	88	369	730
Gain on sale of property and equipment		1,366
Research and Development Expenses
Property and equipment
Depreciation and amortization expense	1	169	290
Computer Equipment and Software
Property and equipment
Property and Equipment, gross	2,128	2,130
Furniture and Fixtures
Property and equipment
Property and Equipment, gross	1,032	1,032
Leasehold Improvements
Property and equipment
Property and Equipment, gross	355	355
Laboratory and Office Equipment
Property and equipment
Property and Equipment, gross	261	261
Property and equipment sold		$58

Accrued_Expenses_and_Other_Cur2

Accrued Expenses and Other Current Liabilities (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Accrued Expenses and Other Current Liabilities
Clinical trials	$929	$1,127
Net deferred income tax liabilities	319	156
General and administrative	267	497
Employee compensation	160	1,354
Product returns	112	586
Research and development	63	39
Accrued expenses and other current liabilities	$1,850	$3,759

Stockholders_Equity_Details

Stockholders' Equity (Details) (USD $)	3 Months Ended	12 Months Ended	0 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2014	Nov. 14, 2014	Mar. 06, 2014	Dec. 31, 2013
Authorized Capital
Common stock shares authorized	200,000,000	200,000,000			120,000,000
Par value per share (in dollars per share)	$0.00	$0.00			$0.00
Preferred stock shares authorized	5,000,000	5,000,000
Par value per share (in dollars per share)	$0.00	$0.00
Common Stock and Associated Warrant Liability
Warrants issued to purchase shares under private placement			64,311,112
Maximum contingent per share cash settlement price (in dollars per share)			$0.13
Fair value of warrant liability	$30,430	$30,430
Loss on change in fair value of warrant liability	8,804	8,804
Private Placement, November 2014
Common Stock and Associated Warrant Liability
Shares issued			64,311,112
Warrants issued to purchase shares under private placement			64,311,112
Net cash proceeds from public offering after deducting underwriting discounts and commissions and other offering expenses			42,814
Exercise price (in dollars per share)			$0.85
Warrant term			4 years
Maximum contingent per share cash settlement price (in dollars per share)			$0.13
Fair value of warrant liability	30,430	30,430	21,626
Loss on change in fair value of warrant liability		8,804
Expected volatility of warrants (as a percent)		91.00%
Risk free interest rate of warrants (as a percent)		1.50%
Expected life of warrants		4 years 6 months
Expected dividends on warrants		$0
Private Placement, March 2014
Common Stock and Associated Warrant Liability
Shares issued				11,976,048
Warrants issued to purchase shares under private placement				10,179,642
Net cash proceeds from public offering after deducting underwriting discounts and commissions and other offering expenses				21,135
Exercise price (in dollars per share)				$1.67
Warrant term				1 year
Estimated fair value of warrants				$4,478
Expected volatility of warrants (as a percent)				67.00%
Risk free interest rate of warrants (as a percent)				0.12%
Expected life of warrants				1 year
Expected dividends on warrants				$0

Collaboration_and_License_Agre1

Collaboration and License Agreements (Details) (Former Orion Corporation License and Supply Agreement, USD $)	1 Months Ended
In Thousands, unless otherwise specified	Oct. 31, 2012
Former Orion Corporation License and Supply Agreement
Collaboration and license agreements disclosures
Contract termination fee	$1,000

Intangible_Assets_Net_Details

Intangible Assets, Net (Details) (USD $)	0 Months Ended
In Thousands, unless otherwise specified	Jan. 01, 2005	Dec. 31, 2014	Dec. 31, 2013	Jul. 31, 2007
Former Orion Corporation License and Supply Agreement
Intangible assets, net
License fee	$4,826
SARM License Agreement
Intangible assets, net
One-time up-front fee				290
Intangible asset, net		$152	$166

Income_Taxes_Details

Income Taxes (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Deferred income tax assets:
Net federal and state operating loss carryforwards	$139,126	$127,819
Research and development credits	12,754	11,934
Share-based compensation	6,800	8,670
Depreciation and amortization	89	170
Other	69	425
Total deferred tax assets	158,838	149,018
Deferred income tax liabilities:
Other	329	157
Total deferred tax liabilities	329	157
Net deferred tax assets	158,509	148,861
Valuation allowance	-158,509	-148,861
Net deferred tax assets and liabilities	0	0
Valuation allowance disclosure
Increase in valuation allowance	9,648	17,318	8,836
Tax credits
Unrecognized tax benefits	0
Federal
Operating loss carryforwards
Net operating loss carryforwards	358,702
State
Operating loss carryforwards
Net operating loss carryforwards	337,735
Federal and State
Operating loss carryforwards
Deductions related to the exercise of stock options	$2,301

Directors_Deferred_Compensatio1

Directors' Deferred Compensation Plan (Details) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Directors' deferred compensation plan
Non-employee director fee expense which was deferred into stock accounts	$125	$135	$169
Director
Directors' deferred compensation plan
Non-employee director fee expense	247	259	237
Non-employee director fee expense which was deferred into stock accounts	125	135	169
Shares of common stock credited to individual director stock accounts under the Directors' Deferred Compensation Plan	237,100
Amount credited to individual director cash accounts under the Directors' Deferred Compensation Plan	$0

401k_Plan_Details

401(k) Plan (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
	item	Dec. 31, 2013	Dec. 31, 2012
401(k) Plan
Maximum annual contribution per employee who is under the specified age in the current calendar year	$17,500
Age specified for current calendar year to determine employee's contribution	50
Maximum annual contribution per employee who is equal to specified age and older in the current calendar year	23,000
Company's matching contribution to the plan	$200,000	$338,000	$363,000

Commitments_and_Contingencies_

Commitments and Contingencies (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Commitments and Contingencies
Rent expense under operating leases	$513	$674	$963
Operating Lease Commitments
2015	$184

Quarterly_Financial_Data_Unaud2

Quarterly Financial Data (Unaudited) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Expenses:
Research and development expenses	$3,254	$3,362	$7,894	$6,360	$6,088	$6,477	$10,139	$9,614	$20,870	$32,318	$38,887
General and administrative expenses	2,203	1,594	3,052	2,629	3,091	2,483	2,684	3,023	9,478	11,281	10,845
Total expenses	5,457	4,956	10,946	8,989	9,179	8,960	12,823	12,637	30,348	43,599	49,732
Loss from operations	-5,457	-4,956	-10,946	-8,989	-9,179	-8,960	-12,823	-12,637	-30,348	-43,599	-49,732
Other income (expense), net	-284	21	2	2	1,389	23	21	55	-259	1,488	-19
Loss on change in fair value of warrant liability	-8,804								-8,804
Loss from operations before income taxes	($14,545)	($4,935)	($10,944)	($8,987)	($7,790)	($8,937)	($12,802)	($12,582)	($39,411)	($42,111)	($49,751)
Net (loss) income per share - basic and diluted:
Net loss per share (in dollars per share)	($0.13)	($0.06)	($0.15)	($0.14)	($0.12)	($0.14)	($0.20)	($0.20)	($0.48)	($0.67)	($0.43)
Weighted average shares outstanding:
Basic and diluted (in shares)	108,869,121	76,014,531	75,433,302	66,512,069	63,185,389	63,179,394	62,994,771	62,864,140	81,807,706	63,057,142	62,809,219