Legal Matters	9 Months Ended
Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Legal Matters	Legal matters On March 29, 2017, a stockholder derivative lawsuit, or the Stockholder Derivative Action, was filed in Washington Superior Court for the County of Snohomish, or the Snohomish County Superior Court. The complaint names as defendants certain of our current and former executives and members of our board of directors. We are named as a nominal defendant. The Stockholder Derivative Action was largely based on a January 2017 securities class action suit, or the CD33A Class Action, that was filed in the United States District Court for the Western District of Washington and which alleged material misrepresentations and omissions in public statements regarding our business, operational and compliance policies, as well as violations of Sections 10(b) and 20(b) of the Securities Exchange Act. Following the dismissal with prejudice of the CD33A Class Action, on August 30, 2018, the plaintiffs in the Stockholder Derivative Action filed an amended complaint. This complaint alleges that the defendants breached their fiduciary duties by making or failing to correct certain allegedly improper public statements regarding our former SGN-CD33A program and by wasting our assets by allowing certain SGN-CD33A trials to continue. The complaint seeks unspecified damages, disgorgement of compensation, corporate governance changes, and attorneys’ fees and costs. Because the complaint is derivative in nature, it does not seek monetary damages from us. On October 4, 2018, we filed a motion to dismiss the amended complaint for failure to plead demand futility. The plaintiffs' opposition brief is due on November 9, 2018. A hearing on our motion to dismiss is scheduled for December 14, 2018. As a result of this lawsuit, we may incur litigation and indemnification expenses. On March 8, 2018, three purported stockholders of Cascadian filed a Verified Complaint to Compel Inspection of Books and Records under 8 Del. C. §220 in the Delaware Court of Chancery against Cascadian, seeking to inspect books and records in order to determine whether wrongdoing or mismanagement has taken place such that it would be appropriate to file claims for breach of fiduciary duty, and to investigate the independence and disinterestedness of the former Cascadian directors with respect to the Cascadian Acquisition. We filed our answer to this complaint on March 28, 2018. As a result of this lawsuit, we may incur litigation and indemnification expenses. In addition, from time to time in the ordinary course of business we become involved in various lawsuits, claims and proceedings relating to the conduct of our business, including those pertaining to the defense and enforcement of our patent or other intellectual property rights. These proceedings are costly and time consuming. Additionally, successful challenges to our patent or other intellectual property rights through these proceedings could result in a loss of rights in the relevant jurisdiction and may allow third parties to use our proprietary technologies without a license from us or our collaborators.

Legal matters

On March 29, 2017, a stockholder derivative lawsuit, or the Stockholder Derivative Action, was filed in Washington Superior Court for the County of Snohomish, or the Snohomish County Superior Court. The complaint names as defendants certain of our current and former executives and members of our board of directors. We are named as a nominal defendant. The Stockholder Derivative Action was largely based on a January 2017 securities class action suit, or the CD33A Class Action, that was filed in the United States District Court for the Western District of Washington and which alleged material misrepresentations and omissions in public statements regarding our business, operational and compliance policies, as well as violations of Sections 10(b) and 20(b) of the Securities Exchange Act. Following the dismissal with prejudice of the CD33A Class Action, on August 30, 2018, the plaintiffs in the Stockholder Derivative Action filed an amended complaint. This complaint alleges that the defendants breached their fiduciary duties by making or failing to correct certain allegedly improper public statements regarding our former SGN-CD33A program and by wasting our assets by allowing certain SGN-CD33A trials to continue. The complaint seeks unspecified damages, disgorgement of compensation, corporate governance changes, and attorneys’ fees and costs. Because the complaint is derivative in nature, it does not seek monetary damages from us. On October 4, 2018, we filed a motion to dismiss the amended complaint for failure to plead demand futility. The plaintiffs' opposition brief is due on November 9, 2018. A hearing on our motion to dismiss is scheduled for December 14, 2018. As a result of this lawsuit, we may incur litigation and indemnification expenses.

On March 8, 2018, three purported stockholders of Cascadian filed a Verified Complaint to Compel Inspection of Books and Records under 8 Del. C. §220 in the Delaware Court of Chancery against Cascadian, seeking to inspect books and records in order to determine whether wrongdoing or mismanagement has taken place such that it would be appropriate to file claims for breach of fiduciary duty, and to investigate the independence and disinterestedness of the former Cascadian directors with respect to the Cascadian Acquisition. We filed our answer to this complaint on March 28, 2018. As a result of this lawsuit, we may incur litigation and indemnification expenses.

In addition, from time to time in the ordinary course of business we become involved in various lawsuits, claims and proceedings relating to the conduct of our business, including those pertaining to the defense and enforcement of our patent or other intellectual property rights. These proceedings are costly and time consuming. Additionally, successful challenges to our patent or other intellectual property rights through these proceedings could result in a loss of rights in the relevant jurisdiction and may allow third parties to use our proprietary technologies without a license from us or our collaborators.