Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies We conduct product research and development programs through a combination of internal and collaborative programs that include, among others, arrangements with universities, contract research organizations and clinical research sites. We have contractual arrangements with these organizations; however, these contracts are cancelable on 30 days-notice and our obligations under these contracts are largely based on services performed with the exception of our contract manufacturers. Non-cancelable purchase commitments with contract manufacturing organizations amount to $94.5 million, $101.7 million and $41.8 million, for services to be performed in 2020, 2021, and 2022, respectively. Facility Leases We lease our corporate, laboratory and other facilities under an operating lease, which has been subject to several amendments necessary to secure additional space and extend the lease term through March 2023. The facility lease agreement, as amended, contains scheduled rent increases over the lease term. Lease expense was $3.6 million, $2.1 million and $1.8 million for the years ended December 31, 2019, 2018 and 2017, respectively. Our future minimum commitments under our non-cancelable operating leases are disclosed in Note 13, "Leases" to these consolidated financial statements. Guarantees and Indemnifications We indemnify each of our officers and directors for certain events or occurrences, subject to certain limits, while the officer or director is or was serving at our request in such capacity, as permitted under Delaware law and in accordance with our certificate of incorporation and bylaws. The term of the indemnification period lasts as long as an officer or director may be subject to any proceeding arising out of acts or omissions of such officer or director in such capacity. The maximum amount of potential future indemnification is unlimited; however, we currently hold director and officer liability insurance. This insurance allows the transfer of risk associated with our exposure and may enable us to recover a portion of any future amounts paid. We believe that the fair value of these indemnification obligations is minimal. Accordingly, we have not recognized any liabilities relating to these obligations for any period presented. Contingencies While there are no material legal proceedings we are aware of, there is one matter described below, and we may become party to various additional claims and complaints arising in the ordinary course of business. Management does not believe that any ultimate liability resulting from any of these claims will have a material adverse effect on its results of operations, financial position, or liquidity. However, management cannot give any assurance regarding the ultimate outcome of these claims, and their resolution could be material to operating results for any particular period, depending upon the level of income for the period. We recognize accruals for such actions to the extent that we conclude that a loss is both probable and reasonably estimable. We accrue for the best estimate of a loss within a range; however, if no estimate in the range is better than any other, then we accrue the minimum amount in the range. If we determine that a loss is reasonably possible and the loss or range of loss can be estimated, we disclose the possible loss. Unless otherwise noted, it is not possible to determine the outcome of these matters, and we cannot reasonably estimate the maximum potential exposure or the range of possible loss. We did not recognize any accruals for the action described below in our Consolidated Balance Sheets as of December 31, 2019 and 2018, as we did not believe losses were probable. Legal Proceedings On January 16, 2020, a stockholder filed a putative class action against the Company and certain officers (the “Defendants”) in the U.S. District Court for the Northern District of California, captioned Hayden v. Portola Pharmaceuticals, Inc., et al., No. 3:20-cv-00367-VC (N.D. Cal.). On February 7, 2020, another stockholder filed a related putative class action against Defendants, captioned McCutcheon v. Portola Pharmaceuticals, Inc., et al., No. 3:20-cv-00949 (N.D. Cal.). The stockholder plaintiffs allege that the Defendants violated the antifraud provisions of the Securities Exchange Act by making misrepresentations and omissions in public disclosures concerning the Company’s sales of andexanet alfa, marketed as Andexxa in the United States and Ondexxya in Europe, between May 8, 2019 and January 9, 2020. Specifically, plaintiffs allege that the Defendants made materially false and/or misleading statements about the demand for Andexxa, and usage of Andexxa by hospitals and healthcare organizations. Plaintiffs also allege that the Defendants made materially false and/or misleading statements about the Company’s accounting for its reserve for returns, and that the Defendants failed to disclose that the Company was shifting from a short-dated version of Andexxa to a longer-dated version, impacting the reserve for returns and impacting revenue for the Company. The Plaintiffs contend that the alleged fraud was revealed on January 9, 2020, when the Company announced its preliminary unaudited financial results for the fourth quarter of 2019. A lead plaintiff has not yet been appointed, and the Company has not yet responded to the complaints. The plaintiffs seek to recover unspecified monetary relief, interest, and attorneys’ fees and costs. Given the early stage of these proceedings, we cannot presently predict the likelihood of obtaining dismissal of the case, nor can we estimate the possible loss or range of loss at this time.