Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 31, 2017	Mar. 01, 2018	Jun. 30, 2017
Document and Entity Information
Entity Registrant Name	Onconova Therapeutics, Inc.
Entity Central Index Key	0001130598
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Smaller Reporting Company
Entity Public Float			$ 17.8
Entity Common Stock, Shares Outstanding		18,946,163
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	FY

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 4,024	$ 21,450
Receivables	59	31
Prepaid expenses and other current assets	820	1,588
Total current assets	4,903	23,069
Property and equipment, net	64	152
Other non-current assets	12	12
Total assets	4,979	23,233
Current liabilities:
Accounts payable	6,186	5,323
Accrued expenses and other current liabilities	3,335	4,382
Deferred revenue	455	455
Total current liabilities	9,976	10,160
Warrant liability	1,773	3,401
Deferred revenue, non-current	4,091	4,545
Total liabilities	15,840	18,106
Commitments and contingencies
Stockholders' (deficit) equity:
Preferred stock, $0.01 par value, 5,000,000 authorized at December 31, 2017 and 2016, none issued and outstanding at December 31, 2017 and 2016
Common stock, $0.01 par value, 25,000,000 authorized at December 31, 2017 and 2016, 10,771,163 and 6,759,895 shares issued and outstanding at December 31, 2017 and 2016	108	68
Additional paid in capital	350,514	342,484
Accumulated other comprehensive income	3	(31)
Accumulated deficit	(362,316)	(338,224)
Total Onconova Therapeutics, Inc. stockholders' (deficit) equity	(11,691)	4,297
Non-controlling interest	830	830
Total stockholders' (deficit) equity	(10,861)	5,127
Total liabilities and stockholders' (deficit) equity	$ 4,979	$ 23,233

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2017	Dec. 31, 2016
Consolidated Balance Sheets
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	25,000,000	25,000,000
Common stock, shares issued	10,771,163	6,759,895
Common stock, shares outstanding	10,771,163	6,759,895

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Consolidated Statements of Operations
Revenue	$ 787	$ 5,546
Operating expenses:
General and administrative	7,405	9,178
Research and development	19,119	20,071
Total operating expenses	26,524	29,249
Loss from operations	(25,737)	(23,703)
Change in fair value of warrant liability	1,628	3,988
Other income, net	30	62
Net loss before income taxes	(24,079)	(19,653)
Income taxes	13	14
Net loss	(24,092)	(19,667)
Net loss attributable to Onconova Therapeutics, Inc.	$ (24,092)	$ (19,667)
Net loss per share of common stock, basic and diluted (in dollars per share)	$ (2.68)	$ (4.44)
Basic and diluted weighted average shares outstanding (in shares)	9,000,326	4,426,639

Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Consolidated Statements of Comprehensive Loss
Net loss	$ (24,092)	$ (19,667)
Other comprehensive income (loss), before tax:
Foreign currency translation adjustments, net	34	(9)
Other comprehensive income (loss), net of tax	34	(9)
Comprehensive loss	(24,058)	(19,676)
Comprehensive loss attributable to Onconova Therapeutics, Inc	$ (24,058)	$ (19,676)

Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Common Stock	Additional Paid in Capital	Accumulated deficit	Accumulated other comprehensive income (loss)	Non-controlling interest	Total
Balance at Dec. 31, 2015	$ 25	$ 328,564	$ (318,557)	$ (22)	$ 830	$ 10,840
Balance (in shares) at Dec. 31, 2015	2,546,419
Increase (Decrease) in Stockholders' Equity (Deficit)
Net loss			(19,667)			(19,667)
Other comprehensive loss				(9)		(9)
Exercise of stock options		3				3
Exercise of stock options (in shares)	403
Stock-based compensation		3,929				3,929
Shares issued in connection with reverse stock split (in shares)	110
Issuance of common stock and pre-funded warrants, net	$ 37	8,949				8,986
Issuance of common stock and pre-funded warrants, net (in shares)	3,599,786
Issuance of common stock upon exercise of warrants	$ 4					4
Issuance of common stock upon exercise of warrants (in shares)	419,493
Issuance of common stock, net	$ 2	1,039				1,041
Issuance of common stock, net (in shares)	193,684
Balance at Dec. 31, 2016	$ 68	342,484	(338,224)	(31)	830	$ 5,127
Balance (in shares) at Dec. 31, 2016	6,759,895					6,759,895
Increase (Decrease) in Stockholders' Equity (Deficit)
Net loss			(24,092)			$ (24,092)
Other comprehensive loss				34		34
Stock-based compensation		1,710				1,710
Issuance of common stock, net	$ 40	6,320				6,360
Issuance of common stock, net (in shares)	4,011,268
Balance at Dec. 31, 2017	$ 108	$ 350,514	$ (362,316)	$ 3	$ 830	$ (10,861)
Balance (in shares) at Dec. 31, 2017	10,771,163					10,771,163

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Operating activities:
Net loss	$ (24,092)	$ (19,667)
Adjustment to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	88	96
Change in fair value of warrant liabilities	(1,628)	(3,988)
Stock compensation expense	1,710	3,929
Changes in assets and liabilities:
Receivables	(28)	1,473
Prepaid expenses and other current assets	768	244
Accounts payable	863	1,902
Accrued expenses and other current liabilities	(1,047)	653
Deferred revenue	(454)	(455)
Net cash used in operating activities	(23,820)	(15,813)
Financing activities:
Proceeds from the sale of common stock and warrants, net of costs	6,360	17,420
Proceeds from the exercise of stock options		3
Net cash provided by financing activities	6,360	17,423
Effect of foreign currency translation on cash	34	(9)
Net (decrease) increase in cash and cash equivalents	(17,426)	1,601
Cash and cash equivalents at beginning of period	21,450	19,849
Cash and cash equivalents at end of period	$ 4,024	$ 21,450

Nature of Business	12 Months Ended
Nature of Business	Dec. 31, 2017
Nature of Business
Nature of Business	1. Nature of Business Reverse Stock Split All common stock, equity, share and per share amounts in the financial statements and notes have been retroactively adjusted to reflect a one-for-ten reverse stock split which was effective May 31, 2016. The Company Onconova Therapeutics, Inc. (the "Company") was incorporated in the State of Delaware on December 22, 1998 and commenced operations on January 1, 1999. The Company's headquarters are located in Newtown, Pennsylvania. The Company is a clinical-stage biopharmaceutical company focused on discovering and developing novel small molecule product candidates primarily to treat cancer. Using its proprietary chemistry platform, the Company has created an extensive library of targeted anti-cancer agents designed to work against specific cellular pathways that are important to cancer cells. The Company believes that the product candidates in its pipeline have the potential to be efficacious in a variety of cancers. The Company has three clinical-stage product candidates and several preclinical programs. In 2011, the Company entered into a license agreement, as subsequently amended, with SymBio Pharmaceuticals Limited ("SymBio"), which grants SymBio certain rights to commercialize rigosertib in Japan and Korea. In 2012, the Company entered into a development and license agreement with Baxter Healthcare SA, the predecessor in interest to Baxalta GmbH (together with its affiliates, "Baxalta"), pursuant to which the Company granted an exclusive, royalty-bearing license for the research, development, commercialization and manufacture (in specified instances) of rigosertib in all therapeutic indications in Europe. The Baxalta agreement terminated effective August 30, 2016, at which time the rights the Company licensed to Baxalta reverted to the Company at no cost. The Company has retained development and commercialization rights to rigosertib in the rest of the world, including the United States. During 2012, Onconova Europe GmbH was established as a wholly owned subsidiary of the Company for the purpose of further developing business in Europe. In April 2013, GBO, LLC, a Delaware limited liability company, ("GBO") was formed pursuant to an agreement with GVK Biosciences Private Limited, a private limited company located in India, ("GVK") to collaborate and develop two programs using the Company's technology platform. The two preclinical programs sublicensed to GBO have not been developed to clinical stage as initially hoped, and the Company is in discussions with GVK regarding the future of GBO. On May 31, 2016, the Company amended its certificate of incorporation to effect a 1 for 10 reverse stock split of its common stock and to decrease the number of authorized shares of common stock from 75,000,000 to 25,000,000. Liquidity The Company has incurred recurring operating losses since inception. For the year ended December 31, 2017, the Company incurred a net loss of $24,092,000 and as of December 31, 2017 the Company had generated an accumulated deficit of $362,316,000. The Company anticipates operating losses to continue for the foreseeable future due to, among other things, costs related to research, development of its product candidates and its preclinical programs, strategic alliances and its administrative organization. At December 31, 2017, the Company had cash and cash equivalents of $4,024,000. The Company will require substantial additional financing to fund its operations and to continue to execute its strategy. These conditions raise substantial doubt about the Company's ability to continue as a going concern within one year after the date that the financial statements are issued. From its inception through July 2013, the Company raised significant capital through the issuance of ten series of preferred stock. On July 30, 2013, the Company completed its initial public offering (the "IPO") of 594,167 shares of the Company's common stock, par value $0.01 per share ("Common Stock"), at a price of $150.00 per share. The Company received net proceeds of $79,811,000 from the sale, net of underwriting discounts and commissions and other offering expenses. Immediately prior to the consummation of the IPO, all outstanding shares of preferred stock automatically converted into shares of Common Stock at the applicable conversion ratio then in effect. In October 2015 the Company entered into a purchase agreement with Lincoln Park Capital Fund, LLC ("Lincoln Park"). Upon execution of this purchase agreement, Lincoln Park purchased 84,676 shares of the Company's Common Stock for $1,500,000. Subject to the terms and conditions of the purchase agreement, including the effectiveness of a registration statement covering the resale of the shares, the Company may sell additional shares of its Common Stock, having an aggregate offering price of up to $15,000,000 to Lincoln Park from time to time until December 1, 2018. On January 5, 2016, the Company entered into a securities purchase agreement with an institutional investor providing for the issuance and sale by the Company of 193,684 shares of the Company's Common Stock and warrants to purchase 96,842 shares of the Company's Common Stock for aggregate net proceeds of $1.6 million (See Note 18) On July 29, 2016 the Company closed on a rights offering of units of common stock and warrants. The Company issued 3,599,786 shares of common stock, 3,192,022 tradable warrants and 656,400 pre-funded warrants in connection with the rights offering. Net proceeds were approximately $15.8 million. (See Note 18) On April 26, 2017 the Company closed on an underwritten public offering of 2,476,190 shares of Common Stock. On May 17, 2017, the Company sold an additional 363,580 shares as a result of the underwriter's exercise of its over-allotment option. Net proceeds from these transactions were approximately $5.3 million. (See Note 18) On November 14, 2017 the Company closed on a registered direct offering to select accredited investors of 920,000 shares of common stock. Net proceeds were approximately $1.1 million. (See Note 18) On February 12, 2018 the Company closed on an offering of units of common stock and warrants. The Company issued 7,005,000 shares of common stock, pre-funded warrants to purchase 2,942,500 share of common stock, and preferred stock warrants to purchase 1,044,487.5 shares of Series A convertible preferred stock. Each share of Series A convertible preferred stock is convertible into ten shares of common stock. Net proceeds were approximately $8.7 million. (See Note 19) The Company has and may continue to delay, scale-back, or eliminate certain of its research and development activities and other aspects of its operations until such time as the Company is successful in securing additional funding. The Company is exploring various dilutive and non-dilutive sources of funding, including equity financings, strategic alliances, business development and other sources. The future success of the Company is dependent upon its ability to obtain additional funding. There can be no assurance, however, that the Company will be successful in obtaining such funding in sufficient amounts, on terms acceptable to the Company, or at all. The Company currently anticipates that current cash and cash equivalents will be sufficient to meet its anticipated cash requirements into the third quarter of 2018. Accordingly, management has concluded that substantial doubt exists with respect to the Company's ability to continue as a going concern within one year after the date that these financial statements are issued.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2017

Summary of Significant Accounting Policies

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Basis of Presentation

The consolidated financial statements are prepared in conformity with accounting principles generally accepted in the United States ("GAAP"). The financial statements include the consolidated accounts of the Company, its wholly-owned subsidiary, Onconova Europe GmbH, and GBO. All significant intercompany transactions have been eliminated.

All common stock, equity, share and per share amounts in the financial statements and notes have been retroactively adjusted to reflect a one-for-ten reverse stock split which was effective May 31, 2016.

Segment Information

Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision maker, or decision-making group, in deciding how to allocate resources and in assessing performance. The Company views its operations and manages its business in one segment, which is the identification and development of oncology therapeutics.

Use of Estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues, expenses, other comprehensive income and related disclosures. On an ongoing basis, management evaluates its estimates, including estimates related to clinical trial accruals, warrant liability, and allocation of consideration for revenue recognition. The Company bases its estimates on historical experience and other market-specific or other relevant assumptions that it believes to be reasonable under the circumstances. Actual results may differ from those estimates or assumptions.

Concentrations of Credit Risk and Off-Balance Sheet Risk

Financial instruments that potentially subject the Company to concentrations of credit risk are primarily cash and cash equivalents. The Company maintains a portion of its cash and cash equivalent balances in the form of money market accounts with financial institutions that management believes are creditworthy. The Company has no financial instruments with off-balance sheet risk of loss.

Cash and Cash Equivalents

The Company considers all highly liquid investments with original or remaining maturity from the date of purchase of three months or less to be cash equivalents. Cash and cash equivalents include bank demand deposits, marketable securities with maturities of three months or less at purchase, and money market funds that invest primarily in certificates of deposit, commercial paper and U.S. government and U.S. government agency obligations. Cash equivalents are reported at fair value.

Fair Value of Financial Instruments

The carrying amounts reported in the accompanying consolidated financial statements for cash and cash equivalents, accounts payable, and accrued liabilities approximate their respective fair values because of the short-term nature of these accounts. The fair value of the warrant liability is discussed in Note 8, "Fair Value Measurements."

Property and Equipment

Property and equipment are stated at cost, less accumulated depreciation. Property and equipment are depreciated using the straight-line method over the estimated useful lives of the assets. Leasehold improvements are amortized over the useful life of the asset or the lease term, whichever is shorter. Maintenance and repairs are expensed as incurred. The following estimated useful lives were used to depreciate the Company's assets:

		Estimated Useful Life
Lab equipment		5 - 6 years
Software		3 years
Computer and office equipment		5 - 6 years
Leasehold improvements		Shorter of the lease term or estimated useful life

Upon retirement or sale, the cost of the disposed asset and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is recognized.

The Company reviews long-lived assets for impairment when events or changes in circumstances indicate that the carrying value of the assets may not be recoverable. Recoverability is measured by comparison of the assets' book value to future net undiscounted cash flows that the assets are expected to generate. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the book value of the assets exceeds their fair value, which is measured based on the projected discounted future net cash flows generated from the assets. No impairment losses have been recorded through December 31, 2017.

Warrant Accounting

Common stock warrants are accounted for in accordance with applicable accounting guidance provided in ASC Topic 815, Derivatives and Hedging—Contracts in Entity's Own Equity (ASC Topic 815), as either derivative liabilities or as equity instruments depending on the specific terms of the warrant agreement. (See Note 4).

The Company's warrants that are classified as liabilities are recorded at fair value. The warrants are subject to remeasurement at each balance sheet date and any change in fair value is recognized as a component of change in fair value of warrant liability in the consolidated statements of operations. The Company has both tradable and non-tradable warrants. At December 31, 2017, the tradable warrants are classified as level 1 liabilities and the Company uses the Nasdaq quoted market price to estimate the fair value of the related derivative warrant liability. The non-tradable warrants are classified as level 3 liabilities and the Company uses the Black-Scholes pricing model to estimate the fair value of the related derivative warrant liability. (See Note 8 for a discussion of the fair value hierarchy).

Foreign Currency Translation

The reporting currency of the Company and its U.S. subsidiaries is the U.S. dollar. The functional currency of the Company's non-U.S. subsidiary is the local currency. Assets and liabilities of the foreign subsidiary are translated into U.S. dollars based on exchange rates at the end of the period. Revenues and expenses are translated at average exchange rates during the reporting period. Gains and losses arising from the translation of assets and liabilities are included as a component of accumulated other comprehensive income. Gains and losses resulting from foreign currency transactions are reflected within the Company's results of operations. The Company has not utilized any foreign currency hedging strategies to mitigate the effect of its foreign currency exposure.

Revenue Recognition

The Company's revenue is generated primarily through collaborative research and license agreements. The terms of these agreements contain multiple deliverables which may include (i) licenses, (ii) research and development activities, (iii) participation in joint steering committees and (iv) product supply. The terms of these agreements may include nonrefundable upfront license fees, payments for research and development activities, payments based upon the achievement of certain milestones, royalty payments based on product sales derived from the collaboration, and payments for supplying product. In all instances, revenue is recognized only when the price is fixed or determinable, persuasive evidence of an arrangement exists, delivery has occurred or the services have been rendered, collectability of the resulting receivable is reasonably assured, and the Company has fulfilled its performance obligations under the contract.

For arrangements with multiple elements, the Company recognizes revenue in accordance with the Financial Accounting Standards Board ("FASB") Accounting Standards Update ("ASU") No. 2009-13, Multiple-Deliverable Revenue Arrangements ("ASU 2009-13"), which provides guidance for separating and allocating consideration in a multiple element arrangement. The selling prices of deliverables under an arrangement may be derived using third-party evidence ("TPE"), or a best estimate of selling price ("BESP"), if vendor-specific objective evidence of selling price ("VSOE") is not available. The objective of BESP is to determine the price at which the Company would transact a sale if the element within the license agreement was sold on a standalone basis. Establishing BESP involves management's judgment and considers multiple factors, including market conditions and company-specific factors, including those factors contemplated in negotiating the agreements, as well as internally developed models that include assumptions related to market opportunity, discounted cash flows, estimated development costs, probability of success and the time needed to commercialize a product candidate pursuant to the license. In validating the BESP, management considers whether changes in key assumptions used to determine the BESP will have a significant effect on the allocation of the arrangement consideration between the multiple deliverables. The Company may use third-party valuation specialists to assist it in determining BESP. Deliverables under the arrangement are separate units of accounting if (i) the delivered item has value to the customer on a standalone basis and (ii) if the arrangement includes a general right of return relative to the delivered item, delivery or performance of the undelivered item is considered probable and substantially within the Company's control. The arrangement consideration that is fixed or determinable at the inception of the arrangement is allocated to the separate units of accounting based on their relative selling prices. The appropriate revenue recognition model is applied to each element and revenue is accordingly recognized as each element is delivered. Management exercises significant judgment in determining whether a deliverable is a separate unit of accounting.

In determining the separate units of accounting, the Company evaluates whether the license has standalone value to the collaborator based on consideration of the relevant facts and circumstances for each arrangement. Factors considered in this determination include the research and development capabilities of the collaborator and the availability of relevant research expertise in the marketplace. In addition, the Company considers whether or not (i) the collaborator could use the license for its intended purpose without the receipt of the remaining deliverables, (ii) the value of the license was dependent on the undelivered items and (iii) the collaborator or other vendors could provide the undelivered items.

Under a collaborative research and license agreement, a steering committee is typically responsible for overseeing the general working relationships, determining the protocols to be followed in the research and development performed and evaluating the results from the continued development of the product. The Company evaluates whether its participation in joint steering committees is a substantive obligation or whether the services are considered inconsequential or perfunctory. The factors the Company considers in determining if its participation in a joint steering committee is a substantive obligation include: (i) which party negotiated or requested the steering committee, (ii) how frequently the steering committee meets, (iii) whether or not there are any penalties or other recourse if the Company does not attend the steering committee meetings, (iv) which party has decision making authority on the steering committee and (v) whether or not the collaborator has the requisite experience and expertise associated with the research and development of the licensed intellectual property.

Whenever the Company determines that an element is delivered over a period of time, revenue is recognized using either a proportional performance model, if a pattern of performance can be determined or a straight-line model over the period of performance, which is typically the research and development term. Progress achieved under the Company's various clinical research organization contracts are typically used as the measure of performance when applying the proportional performance method. At the end of each reporting period, the Company reassesses its cumulative measure of performance and makes appropriate adjustments, if necessary. The Company recognizes revenue using the proportional performance model whenever the Company is able to make reasonably reliable estimates of the level of effort required to complete its performance obligations under an arrangement. Revenue recognized under the proportional performance model at each reporting period is determined by multiplying the total expected payments under the contract (excluding royalties and payments contingent upon achievement of milestones) by the ratio of the level of effort incurred to date to the estimated total level of effort required to complete the performance obligations under the arrangement. Revenue is limited to the lesser of the cumulative amount of payments received or the cumulative amount of revenue earned, as determined using the proportional performance model as of each reporting period. Alternatively, if the Company is not able to make reasonably reliable estimates of the level of effort required to complete its performance obligations under an arrangement, then revenue under the arrangement is recognized on a straight-line basis over the period expected to be required to complete the Company's performance obligations.

Incentive milestone payments may be triggered either by the results of the Company's research efforts or by events external to it, such as regulatory approval to market a product or attaining agreed-upon sales levels. Consideration that is contingent upon achievement of a milestone is recognized in its entirety as revenue in the period in which the milestone is achieved, but only if the consideration earned from the achievement of a milestone meets all the criteria for the milestone to be considered substantive at the inception of the arrangement. For a milestone to be considered substantive, the consideration earned by achieving the milestone must (i) be commensurate with either the Company's performance to achieve the milestone or the enhancement of the value of the item delivered as a result of a specific outcome resulting from the Company's performance to achieve the milestone, (ii) relate solely to past performance and (iii) be reasonable relative to all deliverables and payment terms in the collaboration agreement.

For events for which the occurrences are contingent solely upon the passage of time or are the result of performance by a third party, the contingent payments will be recognized as revenue when payments are earned, the amounts are fixed and determinable and collectability is reasonably assured.

Royalties are recorded as earned in accordance with the contract terms when third party sales can be reliably measured and collectability is reasonably assured.

Research and Development Expenses

Research and development costs are charged to expense as incurred. These costs include, but are not limited to, license fees related to the acquisition of in-licensed products; employee-related expenses, including salaries, benefits and travel; expenses incurred under agreements with contract research organizations and investigative sites that conduct clinical trials and preclinical studies; the cost of acquiring, developing and manufacturing clinical trial materials; facilities, depreciation and other expenses, which include direct and allocated expenses for rent and maintenance of facilities, insurance and other supplies; and costs associated with preclinical activities and regulatory operations.

Costs for certain development activities, such as clinical trials, are recognized based on an evaluation of the progress to completion of specific tasks using data such as patient enrollment, clinical site activations, or information provided to the Company by its vendors with respect to their actual costs incurred. Payments for these activities are based on the terms of the individual arrangements, which may differ from the pattern of costs incurred, and are reflected in the consolidated financial statements as prepaid or accrued research and development expense, as the case may be.

Comprehensive Loss

Comprehensive loss is defined as the change in equity of a business enterprise during a period from transactions and other events and circumstances from non-owner sources.

Income Taxes

The Company accounts for income taxes under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases using enacted tax rates in effect for the year in which the differences are expected to affect taxable income. The deferred tax asset primarily includes net operating loss and tax credit carry forwards, accrued expenses not currently deductible and the cumulative temporary differences related to certain research and patent costs, which have been charged to expense in the accompanying statements of operations but have been recorded as assets for income tax purposes. The portion of any deferred tax asset for which it is more likely than not that a tax benefit will not be realized must then be offset by recording a valuation allowance. A full valuation allowance has been established against all of the deferred tax assets (see Note 9, "Income Taxes"), as it is more likely than not that these assets will not be realized given the Company's history of operating losses. The Company recognizes the tax benefit from an uncertain tax position only if it is more likely than not to be sustained upon examination based on the technical merits of the position. The amount for which an exposure exists is measured as the largest amount of benefit determined on a cumulative probability basis that the Company believes is more likely than not to be realized upon ultimate settlement of the position.

Stock-Based Compensation Expense

The Company applies the provisions of FASB Accounting Standards Codification ("ASC") Topic 718, Compensation—Stock Compensation ("ASC 718"), which requires the measurement and recognition of compensation expense for all stock-based awards made to employees and non-employees, including employee stock options.

At certain times throughout the Company's history, the chairman of the Company's board of directors, who is also a significant stockholder of the Company (the "Significant Holder"), afforded option holders the opportunity for liquidity in transactions in which options were exercised and the shares of Common Stock issued in connection therewith were simultaneously purchased by the Significant Holder (each, a "Purchase Transaction") (See Note 10). Because the Company had established a pattern of providing cash settlement alternatives for option holders, the Company accounted for its stock-based compensation awards as liability awards. The Company measured liability awards based on the award's intrinsic value on the grant date and then re-measured them at each reporting date until the date of settlement. Compensation expense was recognized on a straight-line basis over the requisite service period for each separately vesting portion of the award. Compensation expense for each period until settlement was based on the change in intrinsic value (or a portion of the change in intrinsic value, depending on the percentage of the requisite service that has been rendered at the reporting date). Changes in the intrinsic value of a liability that occur after the end of the requisite service period were considered compensation expense in the period in which the changes occur. On April 23, 2013, the Company distributed a notification letter to all equity award holders under the 2007 Plan advising them that Purchase Transactions would no longer occur, unless, at the time of a Purchase Transaction, the option holder has held the Common Stock issued upon exercise of options for a period of greater than six months prior to selling such Common Stock to the Significant Holder and that any such sale to the Significant Holder would be at the fair value of the Common Stock on the date of such sale. Based on these new criteria for Purchase Transactions, the Company remeasured options outstanding under the 2007 Plan as of April 23, 2013 to their intrinsic value and reclassified such options from liabilities to stockholders' deficit within the Company's consolidated balance sheets, which amounted to $14,482,000. The remaining expense for these options was recognized on a straight-line basis over the remaining requisite service period. During the year ended December 31, 2016, the remaining $244,000 of expense related to these options was recognized and as of December 31, 2017 and 2016, there was no unrecognized compensation expense related to these unvested awards.

Share-based payment transactions with employees, including grants of employee stock options, are recognized as compensation expense over the requisite service period based on their estimated fair values. ASC 718 also requires significant judgment and the use of estimates, particularly surrounding Black-Scholes assumptions such as stock price volatility over the option term and expected option lives, as well as expected option forfeiture rates, to estimate the grant date fair value of equity-based compensation and requires the recognition of the fair value of stock compensation in the statement of operations.

Clinical Trial Expense Accruals

As part of the process of preparing its financial statements, the Company is required to estimate its expenses resulting from its obligations under contracts with vendors, clinical research organizations and consultants and under clinical site agreements in connection with conducting clinical trials. The financial terms of these contracts are subject to negotiations, which vary from contract to contract and may result in payment flows that do not match the periods over which materials or services are provided under such contracts. The Company's objective is to reflect the appropriate trial expenses in its financial statements by matching those expenses with the period in which services are performed and efforts are expended. The Company accounts for these expenses according to the progress of the trial as measured by patient progression and the timing of various aspects of the trial. The Company determines accrual estimates through financial models taking into account discussion with applicable personnel and outside service providers as to the progress or state of consummation of trials, or the services completed. During the course of a clinical trial, the Company adjusts its clinical expense recognition if actual results differ from its estimates. The Company makes estimates of its accrued expenses as of each balance sheet date based on the facts and circumstances known to it at that time. The Company's clinical trial accruals are dependent upon the timely and accurate reporting of contract research organizations and other third-party vendors. Although the Company does not expect its estimates to be materially different from amounts actually incurred, its understanding of the status and timing of services performed relative to the actual status and timing of services performed may vary and may result in it reporting amounts that are too high or too low for any particular period. For the years ended December 31, 2017 and 2016, there were no material adjustments to the Company's prior period estimates of accrued expenses for clinical trials.

Collaboration Arrangements

A collaboration arrangement is defined as a contractual arrangement that has or may have significant financial milestones associated with success-based development, which include certain arrangements the Company has entered into regarding the research and development, manufacture and/or commercialization of products and product candidates. These collaborations generally provide for non-refundable, upfront license fees, research and development and commercial performance milestone payments, cost sharing and royalty payments. The collaboration agreements with third-parties are performed on a "best efforts" basis with no guarantee of either technological or commercial success. The Company evaluates whether an arrangement is a collaboration arrangement at its inception based on the facts and circumstances specific to the arrangement. The Company reevaluates whether an arrangement qualifies or continues to qualify as a collaboration arrangement whenever there is a change in the anticipated or actual ultimate commercial success of the endeavor. See Note 15, "License and Collaboration Agreements," for a discussion of the Company's arrangements with Baxalta and SymBio.

Basic and Diluted Net Loss Per Share of Common Stock

Basic net loss per share of common stock is computed by dividing net loss applicable to common stockholders by the weighted-average number of shares of Common Stock outstanding during the period, excluding the dilutive effects of stock options and warrants. Diluted net loss per share of common stock is computed by dividing the net loss applicable to common stockholders by the sum of the weighted-average number of shares of Common Stock outstanding during the period plus the potential dilutive effects of stock options and warrants outstanding during the period calculated in accordance with the treasury stock method, but are excluded if their effect is anti-dilutive. Because the impact of these items is anti-dilutive during periods of net loss, there was no difference between basic and diluted net loss per share of Common Stock for the years ended December 31, 2017 and 2016.

Recent Accounting Pronouncements

In May 2014, the FASB issued Accounting Standards Update No. 2014-09, "Revenue from Contracts with Customers" (ASU 2014-09) and has subsequently issued a number of amendments to ASU 2014-09. The new standard, as amended, provides a single comprehensive model to be used in the accounting for revenue arising from contracts with customers and supersedes current revenue recognition guidance, including industry-specific guidance. The underlying principle is that an entity will recognize revenue to depict the transfer of goods or services to customers at an amount that the entity expects to be entitled to in exchange for those goods or services. The guidance permits two methods of adoption: retrospectively to each prior reporting period presented (the full retrospective method), or retrospectively with the cumulative effect of initially applying the guidance recognized at the date of initial application (the modified retrospective method). The guidance was effective for interim and annual periods beginning on or after December 15, 2017. Early adoption was permitted but not before December 15, 2016. The Company adopted the new standard effective January 1, 2018 under the modified retrospective method. During the fourth quarter of 2017, the Company substantially completed its assessment of the impact that this new standard will have on its consolidated financial statements. Preliminarily, the Company does not expect the implementation of ASU 2014-09 to have a material quantitative impact on its consolidated financial statements as the timing of revenue recognition under the Company's current license agreements is not expected to significantly change. The finalization of the Company's assessment may result in significant changes to estimates that may materially impact the preliminary estimate of the cumulative effect. The adoption of the new guidance will also result in some additional disclosures.

In August 2014, the FASB issued guidance on determining when and how to disclose going-concern uncertainties in the financial statements. The new standard requires management to perform interim and annual assessments of an entity's ability to continue as a going concern within one year of the date the financial statements are issued. An entity must provide certain disclosures if conditions or events raise substantial doubt about the entity's ability to continue as a going concern. The guidance applies to all entities and is effective for annual periods ending after December 15, 2016, and interim periods thereafter, with early adoption permitted. The Company adopted the new guidance as of December 31, 2016. Based on its current cash position and an evaluation of expected future net cash outflows the Company has determined there is substantial doubt about its ability to continue as a going concern (See Note 1).

In February 2016, the FASB issued guidance which supersedes much of the current guidance for leases. The new standard requires lessees to recognize a right-of-use asset and a lease liability on their balance sheets for all the leases with terms greater than twelve months. Based on certain criteria, leases will be classified as either financing or operating, with classification affecting the pattern of expense recognition in the income statement. For leases with a term of twelve months or less, a lessee is permitted to make an accounting policy election by class of underlying asset not to recognize lease assets and lease liabilities. If a lessee makes this election, it should recognize lease expense for such leases generally on a straight-line basis over the lease term. The guidance is effective for fiscal years beginning after December 15, 2018, and interim periods within those years, with early adoption permitted. In transition, lessees and lessors are required to recognize and measure leases at the beginning of the earliest period presented using a modified retrospective approach. The modified retrospective approach includes a number of optional practical expedients primarily focused on leases that commenced before the effective date of the new guidance, including continuing to account for leases that commence before the effective date in accordance with previous guidance, unless the lease is modified. The Company is evaluating the impact of the adoption of the standard on its consolidated financial statements.

In March 2016, the FASB issued guidance that addresses the income tax effects of stock-based payments and eliminates the windfall pool concept, as all of the tax effects related to stock-based payments will now be recorded at settlement (or expiration) through the income statement. The new guidance also permits entities to make an accounting policy election for the impact of forfeitures on the recognition of expense for stock-based payment awards. Forfeitures can be estimated or recognized when they occur. The standard was effective for annual periods beginning after December 15, 2016 and interim periods within that reporting period. Early adoption was permitted in any interim or annual period, with any adjustment reflected as of the beginning of the fiscal year of adoption. The Company adopted the new guidance as of January 1, 2017. The adoption did not have a material impact on the Company's consolidated financial statements and related disclosures.

In November 2016, the FASB issued guidance requiring that amounts generally described as restricted cash and restricted cash equivalents be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. The guidance is effective for interim and annual periods beginning in 2018 and should be applied using a retrospective transition method to each period presented. Early adoption is permitted. The Company adopted this guidance effective December 31, 2017. Restricted Cash was $50,000 at December 31 2017, 2016 and 2015. The adoption did not have a material impact on the Company's consolidated financial statements and related disclosures.

Property and Equipment

12 Months Ended

Dec. 31, 2017

Property and Equipment

Property and Equipment

3. Property and Equipment

Property and equipment and related accumulated depreciation are as follows:

	December 31,
	2017			2016
Laboratory equipment	$	1,037,000		$	1,037,000
Software		92,000			92,000
Computer and office equipment		354,000			354,000
Leasehold improvements		745,000			745,000

		2,228,000			2,228,000
Less accumulated depreciation		(2,164,000	)		(2,076,000	)

	$	64,000		$	152,000

Depreciation and amortization expense was $88,000 and $96,000 for the years ended December 31, 2017 and 2016, respectively.

Warrants

12 Months Ended

Dec. 31, 2017

Warrants

Warrants

4. Warrants

Warrants outstanding at December 31, 2016 and 2017, and warrant activity for the year ended December 31, 2017 is as follows:

Description	Classification	Exercise Price		Expiration Date		Balance Decemeber 31, 2016		Warrants Issued		Warrants Exercised			Warrants Expired		Balance December 31, 2017
Non-tradable warrants	Liability	$	11.50		July 2021		96,842		—		—			—		96,842
Tradable warrants	Liability	$	4.92		July 2021		3,192,022		—		—			—		3,192,022
Non-tradable pre-funded warrants	Equity	$	0.01		July 2023		236,907		—		(231,000	)		—		5,907

							3,525,771		—		(231,000	)		—		3,294,771

Net Loss Per Share of Common Stock

12 Months Ended

Dec. 31, 2017

Net Loss Per Share of Common Stock

Net Loss Per Share of Common Stock

5. Net Loss Per Share of Common Stock

The following table sets forth the computation of basic and diluted earnings per share for the years ended December 31, 2017 and 2016:

	Year ended December 31,
	2017			2016
Basic and diluted net loss per share of common stock:
Net loss attributable to Onconova Therapeutics, Inc	$	(24,092,000	)	$	(19,667,000	)


Weighted average shares of common stock outstanding		9,000,326			4,426,639


Net loss per share of common stock—basic and diluted	$	(2.68	)	$	(4.44	)

The following potentially dilutive securities outstanding at December 31, 2017 and 2016 have been excluded from the computation of diluted weighted average shares outstanding, as they would be antidilutive:

	December 31,
	2017		2016
Warrants		3,294,771		3,525,771
Stock options		894,996		746,353

		4,189,767		4,272,124

Revenue

12 Months Ended

Dec. 31, 2017

Revenue

Revenue

6. Revenue

The Company recognized revenue under its funding, license and collaboration agreements with Baxalta and SymBio as follows:

	Year ended December 31,
	2017		2016
Baxalta	$	—	$	4,999,000
SymBio		787,000		547,000

	$	787,000	$	5,546,000

See Note 14, "Research Agreements," and Note 15, "License and Collaboration Agreements," for a further discussion of the agreements with Baxalta and SymBio.

Balance Sheet Detail

12 Months Ended

Dec. 31, 2017

Balance Sheet Detail

Balance Sheet Detail

7. Balance Sheet Detail

Prepaid expenses and other current assets are as follows:

	December 31,
	2017		2016
Research and development	$	514,000	$	1,075,000
Manufacturing		48,000		90,000
Insurance		181,000		350,000
Other		77,000		73,000

	$	820,000	$	1,588,000

Accrued expenses and other current liabilities are as follows:

	December 31,
	2017		2016
Research and development	$	1,912,000	$	2,376,000
Employee compensation		1,258,000		1,573,000
Professional fees		165,000		235,000
Other		—		198,000

	$	3,335,000	$	4,382,000

Fair Value Measurements

12 Months Ended

Dec. 31, 2017

Fair Value Measurements

Fair Value Measurements

8. Fair Value Measurements

Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date.

The Company utilizes a valuation hierarchy for disclosure of the inputs to the valuations used to measure fair value. This hierarchy prioritizes the inputs into three broad levels as follows. Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities. Level 2 inputs are quoted prices for similar assets and liabilities in active markets or inputs that are observable for the asset or liability, either directly or indirectly through market corroboration, for substantially the full term of the financial instrument. Level 3 inputs are unobservable inputs based on the Company's own assumptions used to measure assets and liabilities at fair value. A financial asset or liability's classification within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement.

On January 5, 2016, the Company entered into a securities purchase agreement (the "Securities Purchase Agreement") with an institutional investor providing for the issuance and sale by the Company of 193,684 shares of the Company's Common Stock, at a purchase price of $9.50 per share and warrants to purchase up to 96,842 shares of the Company's Common Stock (the "Warrants") for aggregate gross proceeds of $1,840,000 (see Note 18). The Company has classified the warrants as a liability (see Note 4). The fair value was estimated using the Black-Scholes pricing model.

On July 29, 2016 the Company closed on a Rights Offering, issuing 3,599,786 shares of Common Stock, 3,192,022 Tradable Warrants and 656,400 Pre-Funded Warrants. The Tradable Warrants are exercisable for a period of five years for one share of Common Stock at an exercise price of $4.92 per share. After the one-year anniversary of issuance, the Company may redeem the Tradable Warrants for $0.001 per Tradable Warrant if the volume weighted average price of its Common Stock is above $12.30 for each of 10 consecutive trading days (see Note 18). The Company has classified the Tradable Warrants as a liability (see Note 4). The Tradable Warrants have been listed on the NASDAQ Capital Market since issuance and the Company regularly monitors the trading activity. During the period from issuance on July 29, 2016 through March 31, 2017 the Company determined that trading volume was insufficient to use the NASDAQ Capital Market value to determine the fair value of the warrant liability. The fair value was estimated using the Black-Scholes pricing model. During the quarter ended June 30, 2017, the Company determined that an active and orderly market for the Tradable Warrants had developed and that the NASDAQ Capital Market price was the best indicator of fair value of the warrant liability. Consequently, the Company changed its valuation technique from the Black-Scholes pricing model to the quoted market price, effective April 1, 2017. The change in valuation technique resulted in a reclassification of the liability within the valuation hierarchy form Level 3 to Level 1. The quoted market price was also used to determine the fair value at December 31, 2017.

The Company estimated the fair value of the non-tradable warrant liability at December 31, 2017, using the Black-Scholes option pricing model with the following weighted-average assumptions:

Risk-free interest rate		2.09%
Expected volatility		75.47%
Expected term		3.53 years
Expected dividend yield		0%

Expected volatility is based on the historical volatility of the Company's common stock since its IPO in July 2013.

The following fair value hierarchy table presents information about the Company's financial assets and liabilities measured at fair value on a recurring basis as of December 31, 2017 and 2016:

	Fair Value Measurement as of:
	December 31, 2017								December 31, 2016
	Level 1		Level 2		Level 3		Balance		Level 1		Level 2		Level 3		Balance
Tradable warrants liability	$	1,755,000	$	—	$	—	$	1,755,000	$	—	$	—	$	3,338,000	$	3,338,000
Non-tradable warrants liability		—		—		18,000		18,000		—		—		63,000		63,000

Total	$	1,755,000	$	—	$	18,000	$	1,773,000	$	—	$	—	$	3,401,000	$	3,401,000

The following table presents a reconciliation of the Company's liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for the years ended December 31, 2017 and 2016:

	Warrant Liability
Balance at December 31, 2015	$	—
Issuance of warrants		7,389,000

Change in fair value upon re-measurement		(3,988,000	)

Balance at December 31, 2016	$	3,401,000


Reclassification of tradable warrants to Level 1	$	(4,857,000	)
Change in fair value upon re-measurement		1,474,000

Balance at December 31, 2017	$	18,000

There were no transfers between Level 1 and Level 2 in any of the periods reported.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Income Taxes

12 Months Ended

Dec. 31, 2017

Income Taxes

Income Taxes

9. Income Taxes

The Company accounts for income taxes under FASB ASC 740 ("ASC 740"). Deferred income tax assets and liabilities are determined based upon differences between financial reporting and tax bases of assets and liabilities, which are measured using the enacted tax rates and laws that will be in effect when the differences are expected to reverse.

Income taxes have been based on the following income (loss) before income tax expense:

	December 31,
	2017			2016
Domestic	$	(24,131,000	)	$	(19,738,000	)
Foreign		52,000			85,000

	$	(24,079,000	)	$	(19,653,000	)

The provision for income taxes consists of the following:

	December 31,
	2017		2016
Current
US Federal	$	—	$	—
State and Local		—		—
Foreign		13,000		14,000

Total Current	$	13,000	$	14,000

Deferred
US Federal	$	—	$	—
State and Local		—		—
Foreign		—		—

Total Deferred	$	—	$	—

Total Expense (Benefit)	$	13,000	$	14,000

As of December 31, 2017, the Company had federal net operating loss ("NOL") carry forwards of $210,529,000, state NOL carry forwards of $169,672,000 and research and development tax credit carry forwards of $79,725,000, which are available to reduce future taxable income. The federal NOL and tax credit carry forwards will begin to expire at various dates starting in 2022. The state NOL carry forwards will begin to expire at various dates starting in 2025. The NOL carry forwards are subject to review and possible adjustment by the Internal Revenue Service and state tax authorities. NOL and tax credit carry forwards may become subject to an annual limitation in the event of certain cumulative changes in the ownership interest of significant stockholders over a three-year period in excess of 50%, as defined under Sections 382 and 383 of the Internal Revenue Code of 1986, as amended, as well as similar state tax provisions. This could limit the amount of NOLs that the Company can utilize annually to offset future taxable income or tax liabilities. The amount of the annual limitation, if any, will be determined based on the value of the Company immediately prior to the ownership change. Subsequent ownership changes may further affect the limitation in future years.

The Company's reserves related to taxes are based on a determination of whether and how much of a tax benefit taken by the Company in its tax filings or positions is more likely than not to be realized. The Company recognized no material adjustment for unrecognized income tax benefits. Through December 31, 2017, the Company had no unrecognized tax benefits or related interest and penalties accrued.

The principal components of the Company's deferred tax assets are as follows:

	December 31,
	2017			2016
Deferred tax assets:
Net operating loss carryovers	$	57,557,000		$	75,829,000
R&D tax credits		79,725,000			71,811,000
Non-qualified stock options		5,355,000			7,413,000
Deferred revenue		1,242,000			2,030,000
Charitable contributions		4,000			6,000
Accrued expenses		407,000			618,000
Fixed assets		85,000			102,000

Deferred tax assets		144,375,000			157,809,000
Less valuation allowance		(144,375,000	)		(157,809,000	)

Net deferred tax assets	$	—		$	—

ASC 740 requires a valuation allowance to reduce the deferred tax assets reported if, based on the weight of available evidence, it is more likely than not that some portion or all of the deferred tax assets will not be realized. After consideration of all the evidence, both positive and negative, the Company has recorded a full valuation allowance against its deferred tax assets at December 31, 2017 and 2016, respectively. The Company experienced a net change in valuation allowance of $(13,434,000) and $8,738,000 for the years ended December 31, 2017 and 2016, respectively.

A reconciliation of income tax (expense) benefit at the statutory federal income tax rate and income taxes as reflected in the financial statements is as follows:

	December 31,
	2017			2016
Federal income tax expense at statutory rate		34.0	%		34.0	%
Permanent items		(8.1	)		(5.9	)
Effect of Tax Act		(116.9	)		—
State income tax, net of federal benefit		5.8			(15.8	)
Tax credits		29.3			33.5
Provision to return		—			(1.5	)
Change in valuation allowance		55.8			(44.5	)
Other		—			0.1

Effective income tax rate		(0.1	)%		(0.1	)%

On December 22, 2017, H.R. 1 (also, known as the Tax Cuts and Jobs Act (the "Act")) was signed into law. Among its numerous changes to the Internal Revenue Code, the Act reduces U.S. federal corporate tax rate from 34% to 21% and imposes a one-time transition tax on unrepatriated earnings of foreign subsidiaries. As a result, the Company believes that the most significant impact on its consolidated financial statements will be reduction of approximately $28.1 million for the deferred tax assets related to net operating losses and other assets. Such reduction is offset by changes to the Company's valuation allowance. The one-time mandatory transition tax on accumulated foreign earnings resulted in a provisional amount of income of $115,000 for the Company, which the company is offsetting with its net operating loss.

Stock-Based Compensation

12 Months Ended

Dec. 31, 2017

Stock-Based Compensation

Stock-Based Compensation

10. Stock-Based Compensation

In January 2008, the board of directors approved the 2007 Equity Compensation Plan (the "2007 Plan"), which amended, restated and renamed the Company's 1999 Stock Based Compensation Plan (the "1999 Plan"), which provided for the granting of incentive and nonqualified stock options and restricted stock to its employees, directors and consultants at the discretion of the board of directors.

Further, in July 2013, the Company's board of directors and stockholders approved the 2013 Equity Compensation Plan (the "2013 Plan"), which amended, restated and renamed the 2007 Plan. Under the 2013 Plan, the Company may grant incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock, restricted stock units, deferred share awards, performance awards and other equity-based awards to employees, directors and consultants. The Company initially reserved 610,783 shares of Common Stock for issuance, subject to adjustment as set forth in the 2013 Plan. The 2013 Plan includes an evergreen provision, pursuant to which the maximum aggregate number of shares that may be issued under the 2013 Plan is increased on the first day of each fiscal year by the lesser of (a) a number of shares equal to four percent (4%) of the issued and outstanding Common Stock of the Company, without duplication, (b) 200,000 shares and (c) such lesser number as determined by the Company's board of directors, subject to specified limitations. At December 31, 2017, there were 57,632 shares available for future issuance.

Stock-based compensation expense includes stock options granted to employees and non-employees and has been reported in the Company's statements of operations and comprehensive loss in either research and development expenses or general and administrative expenses depending on the function performed by the optionee. No net tax benefits related to the stock-based compensation costs have been recognized since the Company's inception. The Company recognized stock-based compensation expense as follows for years ended December 31, 2017 and 2016:

	Year ended December 31,
	2017		2016
General and administrative	$	975,000	$	1,887,000
Research and development		735,000		2,042,000

	$	1,710,000	$	3,929,000

A summary of stock option activity for the year ended December 31, 2017 is as follows:

				Options Outstanding
	Shares Available for Grant			Number of Shares			Weighted- Average Exercise Price		Weighted Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value
Balance, December 31, 2016		6,275			746,353		$	53.50		7.70	$	0
Authorized		200,000			—
Granted		(198,811	)		198,811		$	2.57
Exercised		—			—		$	—
Forfeitures		50,168			(50,168	)	$	85.25

Balance, December 31, 2017		57,632			894,996		$	40.41		7.38	$	0

Vested or expected to vest, December 31, 2017					882,972		$	57.02		6.72	$	0

Exercisable at December 31, 2017					604,555		$	57.02		6.72	$	0