License Agreements	12 Months Ended
Dec. 31, 2019
Research And Development [Abstract]
License Agreements	5. License Agreements License and Compound Library and Option Agreement and Related License Agreements with Ascentage The Company is a party to three agreements with Ascentage Pharma Group Corp. Limited, a clinical-stage biopharmaceutical company based in Hong Kong, China (“Ascentage Pharma”): (a) a compound library and option agreement executed in February 2016 granting the Company the right to identify and take licenses to research, develop, and seek and obtain marketing approval for library compounds for the treatment of indications outside of oncology, (b) an initial license agreement executed in February 2016 granting the Company rights to an initial licensed compound, and (c) a second license agreement executed in January 2019 granting the Company rights to a second licensed compound (collectively, the “Commercial Agreements”). As of December 31, 2019, as part of these agreements, the Company had issued 640,002 shares of common stock to Ascentage Pharma and 160,000 shares of common stock to an academic institution from whom Ascentage Pharma had previously licensed the technology. The Commercial Agreements referenced above include cash payments of up to $70.3 million as well as remaining equity payments of up to an aggregate 533,336 additional shares of common stock, in each case to be issued based on the Company’s achievement of certain specified clinical development and sales milestone events. The milestones include the filing of an investigational drug application, the commencement of clinical studies, Food and Drug Administration and/or European Medicines Agency approval, and a net sales threshold. The license agreement also includes tiered royalties in the low-single digits based on sales of licensed products. In December 2018, the Company elected to advance the second compound into formal preclinical development which gave rise to an obligation under the compound library and option agreement to issue 133,334 shares of common stock to Ascentage Pharma and the academic institution. These shares were issued to Ascentage Pharma in January 2019 and the academic institution in March 2019. In connection with the additional shares of common stock that the Company may be obligated to issue under the Commercial Agreements upon achievement of the specified milestones events, the Company recorded a contingent consideration liability of $1.1 million at December 31, 2019 and $2.5 million at December 31, 2018. The $1.1 million contingent consideration liability was recorded as a current liability based on the latest estimates for milestone achievements. To date, no royalties were due from the sales of licensed products. In April 2016, in connection with the Commercial Agreements the Company purchased an interest in an affiliate of Ascentage Pharma for an aggregate purchase price of $0.5 million. In May 2018, this interest was exchanged for an interest in a newly formed affiliate of Ascentage Pharma called Ascentage Pharma Group International (“Ascentage International”) as part of a reorganization of those entities. The Company also invested an additional $0.5 million in Ascentage International in May 2018 which was recorded within other long-term assets on the Company’s balance sheet as of December 31, 2018. In October 2019, Ascentage International completed an initial public offering of shares of its common stock on the Hong Kong stock exchange at HK$34.20 (approximately USD $4.36) per share. In connection with Ascentage International’s initial public offering, the Company’s interest converted into shares of common stock of Ascentage International. The Company determined that its investment in Ascentage International met the definition of an equity security with a readily determinable fair value which is measured at fair value on a recurring basis based on quoted stock price available on the Hong Kong Stock Exchange. The Company is subject to a lock-up agreement with Ascentage International that precludes the Company from selling shares prior to April 2020. The fair value of the Company’s investment in Ascentage International as of December 31, 2019 was $5.5 million, which was included in strategic investments. The fair value investment of the Company’s in Ascentage International as of December 31, 2018 was $1.0 million, which was included in other long-term assets. The Company agreed to provide funding to Ascentage Pharma for research and development work performed at a cost of up to $2.0 million through February 2020. The research and development expense under the research services agreement was $0.5 million and $0.5 million for the years ended December 31, 2019 and 2018. Under the consolidation guidance, the Company had previously determined that Ascentage Pharma was a VIE and the Company did not have the power to direct the activities that most significantly affect the economic performance of this entity. As such, the Company was not the primary beneficiary and consolidation is not required. Upon completion of its initial public offering of common stock on the Hong Kong stock exchange, the Company determined that Ascentage Pharma no longer meets the definition of a VIE. As of December 31, 2019 and 2018, the Company has not provided financial, or other, support to Ascentage Pharma that was not contractually required. Other License Agreements with Research Institutions In May 2019, the Company entered into a license agreement with The Regents of the University of California on behalf its San Francisco campus (collectively, “UCSF”) which provides the Company the rights to certain patents and related know-how to make, use, sell, offer for sale and import certain products and practice certain methods for use in the development of human therapeutics, which excludes the provision of services to third parties for consideration of any kind. The license to the Company is subject to UCSF’s reserved rights under the licensed intellectual property for educational and non-commercial research purposes and a requirement to substantially manufacture any licensed products in the United States. The Company is obligated to use diligent efforts to develop and obtain regulatory approval for at least one product commercialized pursuant to the agreement, and must meet certain regulatory and development milestones. In June 2019, as part of this license agreement, the Company issued 120,000 shares of its common stock to UCSF. In addition, the Company is obligated to pay an annual license maintenance fee and may be obligated to make milestone payments or issue up to an additional 34,000 shares of its common stock upon the occurrence of specified development events, up to aggregate milestone payments of $13.6 million for each product licensed under the agreement, and upon commercialization, to make royalty payments in the low single digit percentages (subject to a specified minimum annual royalty) based on net sales of products commercialized pursuant to the agreement. None of these events had occurred and no milestone payments or royalty payments had been recognized as of December 31, 2019. The upfront issuance of 120,000 shares of the Company’s common stock was valued at $1.0 million at the time of issuance and recorded as additional paid-in capital upon issuance in June 2019. The Company has also entered into license agreements with various research institutions which have provided the Company with rights to patents, and in certain cases, research “know-how” and proprietary research tools to research, develop and commercialize drug candidates. In addition to upfront consideration paid to these various research institutions in either cash or shares of the Company’s common stock, the Company may be obligated to make milestone payments, payable in cash and/or the issuance of shares of the Company’s common stock upon achievement of certain specified clinical development and/or sales events. The contingent consideration liability considered to be a derivative associated with the potential issuance of common stock related to these license agreements was not significant at December 31, 2019 or 2018. To date, none of these events has occurred and no contingent consideration, milestone or royalty payments have been recognized.

License Agreements

12 Months Ended

Dec. 31, 2019

5. License Agreements

License and Compound Library and Option Agreement and Related License Agreements with Ascentage

The Company is a party to three agreements with Ascentage Pharma Group Corp. Limited, a clinical-stage biopharmaceutical company based in Hong Kong, China (“Ascentage Pharma”): (a) a compound library and option agreement executed in February 2016 granting the Company the right to identify and take licenses to research, develop, and seek and obtain marketing approval for library compounds for the treatment of indications outside of oncology, (b) an initial license agreement executed in February 2016 granting the Company rights to an initial licensed compound, and (c) a second license agreement executed in January 2019 granting the Company rights to a second licensed compound (collectively, the “Commercial Agreements”). As of December 31, 2019, as part of these agreements, the Company had issued 640,002 shares of common stock to Ascentage Pharma and 160,000 shares of common stock to an academic institution from whom Ascentage Pharma had previously licensed the technology.

The Commercial Agreements referenced above include cash payments of up to $70.3 million as well as remaining equity payments of up to an aggregate 533,336 additional shares of common stock, in each case to be issued based on the Company’s achievement of certain specified clinical development and sales milestone events. The milestones include the filing of an investigational drug application, the commencement of clinical studies, Food and Drug Administration and/or European Medicines Agency approval, and a net sales threshold. The license agreement also includes tiered royalties in the low-single digits based on sales of licensed products.

In December 2018, the Company elected to advance the second compound into formal preclinical development which gave rise to an obligation under the compound library and option agreement to issue 133,334 shares of common stock to Ascentage Pharma and the academic institution. These shares were issued to Ascentage Pharma in January 2019 and the academic institution in March 2019. In connection with the additional shares of common stock that the Company may be obligated to issue under the Commercial Agreements upon achievement of the specified milestones events, the Company recorded a contingent consideration liability of $1.1 million at December 31, 2019 and $2.5 million at December 31, 2018. The $1.1 million contingent consideration liability was recorded as a current liability based on the latest estimates for milestone achievements. To date, no royalties were due from the sales of licensed products.

In April 2016, in connection with the Commercial Agreements the Company purchased an interest in an affiliate of Ascentage Pharma for an aggregate purchase price of $0.5 million. In May 2018, this interest was exchanged for an interest in a newly formed affiliate of Ascentage Pharma called Ascentage Pharma Group International (“Ascentage International”) as part of a reorganization of those entities. The Company also invested an additional $0.5 million in Ascentage International in May 2018 which was recorded within other long-term assets on the Company’s balance sheet as of December 31, 2018.

In October 2019, Ascentage International completed an initial public offering of shares of its common stock on the Hong Kong stock exchange at HK$34.20 (approximately USD $4.36) per share. In connection with Ascentage International’s initial public offering, the Company’s interest converted into shares of common stock of Ascentage International. The Company determined that its investment in Ascentage International met the definition of an equity security with a readily determinable fair value which is measured at fair value on a recurring basis based on quoted stock price available on the Hong Kong Stock Exchange. The Company is subject to a lock-up agreement with Ascentage International that precludes the Company from selling shares prior to April 2020. The fair value of the Company’s investment in Ascentage International as of December 31, 2019 was $5.5 million, which was included in strategic investments. The fair value investment of the Company’s in Ascentage International as of December 31, 2018 was $1.0 million, which was included in other long-term assets.

The Company agreed to provide funding to Ascentage Pharma for research and development work performed at a cost of up to $2.0 million through February 2020. The research and development expense under the research services agreement was $0.5 million and $0.5 million for the years ended December 31, 2019 and 2018.

Under the consolidation guidance, the Company had previously determined that Ascentage Pharma was a VIE and the Company did not have the power to direct the activities that most significantly affect the economic performance of this entity. As such, the Company was not the primary beneficiary and consolidation is not required. Upon completion of its initial public offering of common stock on the Hong Kong stock exchange, the Company determined that Ascentage Pharma no longer meets the definition of a VIE. As of December 31, 2019 and 2018, the Company has not provided financial, or other, support to Ascentage Pharma that was not contractually required.

Other License Agreements with Research Institutions

In May 2019, the Company entered into a license agreement with The Regents of the University of California on behalf its San Francisco campus (collectively, “UCSF”) which provides the Company the rights to certain patents and related know-how to make, use, sell, offer for sale and import certain products and practice certain methods for use in the development of human therapeutics, which excludes the provision of services to third parties for consideration of any kind. The license to the Company is subject to UCSF’s reserved rights under the licensed intellectual property for educational and non-commercial research purposes and a requirement to substantially manufacture any licensed products in the United States. The Company is obligated to use diligent efforts to develop and obtain regulatory approval for at least one product commercialized pursuant to the agreement, and must meet certain regulatory and development milestones. In June 2019, as part of this license agreement, the Company issued 120,000 shares of its common stock to UCSF. In addition, the Company is obligated to pay an annual license maintenance fee and may be obligated to make milestone payments or issue up to an additional 34,000 shares of its common stock upon the occurrence of specified development events, up to aggregate milestone payments of $13.6 million for each product licensed under the agreement, and upon commercialization, to make royalty payments in the low single digit percentages (subject to a specified minimum annual royalty) based on net sales of products commercialized pursuant to the agreement. None of these events had occurred and no milestone payments or royalty payments had been recognized as of December 31, 2019. The upfront issuance of 120,000 shares of the Company’s common stock was valued at $1.0 million at the time of issuance and recorded as additional paid-in capital upon issuance in June 2019.

The Company has also entered into license agreements with various research institutions which have provided the Company with rights to patents, and in certain cases, research “know-how” and proprietary research tools to research, develop and commercialize drug candidates. In addition to upfront consideration paid to these various research institutions in either cash or shares of the Company’s common stock, the Company may be obligated to make milestone payments, payable in cash and/or the issuance of shares of the Company’s common stock upon achievement of certain specified clinical development and/or sales events. The contingent consideration liability considered to be a derivative associated with the potential issuance of common stock related to these license agreements was not significant at December 31, 2019 or 2018. To date, none of these events has occurred and no contingent consideration, milestone or royalty payments have been recognized.