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, 2016, the Company incurred a net loss of $19,667,000 and as of December 31, 2016 the Company had generated an accumulated deficit of $338,224,000. 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, 2016, the Company had cash and cash equivalents of $21,400,000. The Company will require substantial additional financing to fund its operations and to continue to execute its strategy.

        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 estimated 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 2014, the Company entered into a sales agreement with Cantor Fitzgerald & Co. ("Cantor") to create an at-the-market equity program under which the Company had the ability to offer and sell shares of its Common Stock having an aggregate offering price of up to $20,000,000 through Cantor (see Note 18). Net proceeds from sales of Common Stock under this program were $6,018,000 during the year ended December 31, 2015. The sales agreement with Cantor was terminated on January 5, 2016, and there were no sales of Common Stock under this program during the year ended December 31, 2016.

        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)

        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 fourth quarter of 2017. These factors raise substantial doubt about the Company's ability to continue as a going concern within one year after the date that these financial statements are issued.